Merge pull request #1790 from jhogberg/john/erts/more-alloc-info/OTP-14961

Improve memory instrumentation

OTP-15024
OTP-14961

15 files changed, 1483 insertions, 1513 deletions

diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 687fd39d58..bcaf9277bf 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -693,3 +693,5 @@ bif erts_internal:new_connection/1
 bif erts_internal:abort_connection/2
 bif erts_internal:map_next/3
 bif ets:whereis/1
+bif erts_internal:gather_alloc_histograms/1
+bif erts_internal:gather_carrier_info/1
diff --git a/erts/emulator/beam/bif_instrs.tab b/erts/emulator/beam/bif_instrs.tab
index 0932b8b985..0f074280db 100644
--- a/erts/emulator/beam/bif_instrs.tab
+++ b/erts/emulator/beam/bif_instrs.tab
@@ -432,9 +432,17 @@ nif_bif.call_nif() {
         live_hf_end = c_p->mbuf;
         ERTS_CHK_MBUF_SZ(c_p);
         erts_pre_nif(&env, c_p, (struct erl_module_nif*)I[2], NULL);
+
+        ASSERT((c_p->scheduler_data)->current_nif == NULL);
+        (c_p->scheduler_data)->current_nif = &env;
+
         nif_bif_result = (*fp)(&env, bif_nif_arity, reg);
         if (env.exception_thrown)
             nif_bif_result = THE_NON_VALUE;
+
+        ASSERT((c_p->scheduler_data)->current_nif == &env);
+        (c_p->scheduler_data)->current_nif = NULL;
+
         erts_post_nif(&env);
         ERTS_CHK_MBUF_SZ(c_p);
 
diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index ba8cc5e2ba..9ff52c92b8 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -36,7 +36,6 @@
 #include "hash.h"
 #include "atom.h"
 #include "beam_load.h"
-#include "erl_instrument.h"
 #include "erl_hl_timer.h"
 #include "erl_thr_progress.h"
 #include "erl_proc_sig_queue.h"
@@ -955,20 +954,6 @@ erl_crash_dump_v(char *file, int line, char* fmt, va_list args)
     erts_cbprintf(to, to_arg, "=atoms\n");
     dump_atoms(to, to_arg);
 
-    /* Keep the instrumentation data at the end of the dump */
-    if (erts_instr_memory_map || erts_instr_stat) {
-	erts_cbprintf(to, to_arg, "=instr_data\n");
-
-	if (erts_instr_stat) {
-	    erts_cbprintf(to, to_arg, "=memory_status\n");
-	    erts_instr_dump_stat_to(to, to_arg, 0);
-	}
-	if (erts_instr_memory_map) {
-	    erts_cbprintf(to, to_arg, "=memory_map\n");
-	    erts_instr_dump_memory_map_to(to, to_arg);
-	}
-    }
-
     erts_cbprintf(to, to_arg, "=end\n");
     if (fp) {
         fclose(fp);
diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c
index 061b9df627..d99d2ea57b 100644
--- a/erts/emulator/beam/erl_alloc.c
+++ b/erts/emulator/beam/erl_alloc.c
@@ -38,7 +38,7 @@
 #include "erl_db.h"
 #include "erl_binary.h"
 #include "erl_bits.h"
-#include "erl_instrument.h"
+#include "erl_mtrace.h"
 #include "erl_mseg.h"
 #include "erl_monitor_link.h"
 #include "erl_hl_timer.h"
@@ -202,8 +202,6 @@ typedef struct {
     int top_pad;
     AlcUInit_t alloc_util;
     struct {
-	int stat;
-	int map;
 	char *mtrace;
 	char *nodename;
     } instr;
@@ -428,6 +426,7 @@ set_default_binary_alloc_opts(struct au_init *ip)
 #endif
     ip->init.util.ts 		= ERTS_ALC_MTA_BINARY;
     ip->init.util.acul		= ERTS_ALC_DEFAULT_ACUL;
+    ip->init.util.atags		= 1;
 }
 
 static void
@@ -464,6 +463,7 @@ set_default_driver_alloc_opts(struct au_init *ip)
 #endif
     ip->init.util.ts 		= ERTS_ALC_MTA_DRIVER;
     ip->init.util.acul		= ERTS_ALC_DEFAULT_ACUL;
+    ip->init.util.atags		= 1;
 }
 
 static void
@@ -501,6 +501,7 @@ set_default_test_alloc_opts(struct au_init *ip)
     ip->init.util.mmbcs 	= 0; /* Main carrier size */
     ip->init.util.ts 		= ERTS_ALC_MTA_TEST;
     ip->init.util.acul		= ERTS_ALC_DEFAULT_ACUL;
+    ip->init.util.atags		= 1;
 
     /* Use a constant minimal MBC size */
 #if ERTS_SA_MB_CARRIERS
@@ -906,7 +907,6 @@ erts_alloc_init(int *argc, char **argv, ErtsAllocInitOpts *eaiop)
 		       &test_alloc_state);
 
     erts_mtrace_install_wrapper_functions();
-    extra_block_size += erts_instr_init(init.instr.stat, init.instr.map);
 
     init_aireq_alloc();
 
@@ -1411,7 +1411,9 @@ handle_au_arg(struct au_init *auip,
 	    }
 	    if (!strategy_support_carrier_migration(auip))
 		auip->init.util.acul = 0;
-	}
+	} else if (has_prefix("atags", sub_param)) {
+            auip->init.util.atags = get_bool_value(sub_param + 5, argv, ip);
+        }
 	else
 	    goto bad_switch;
 	break;
@@ -1741,24 +1743,6 @@ handle_args(int *argc, char **argv, erts_alc_hndl_args_init_t *init)
 		    break;
 		case 'i':
 		    switch (argv[i][3]) {
-		    case 's':
-			arg = get_value(argv[i]+4, argv, &i);
-			if (sys_strcmp("true", arg) == 0)
-			    init->instr.stat = 1;
-			else if (sys_strcmp("false", arg) == 0)
-			    init->instr.stat = 0;
-			else
-			    bad_value(param, param+3, arg);
-			break;
-		    case 'm':
-			arg = get_value(argv[i]+4, argv, &i);
-			if (sys_strcmp("true", arg) == 0)
-			    init->instr.map = 1;
-			else if (sys_strcmp("false", arg) == 0)
-			    init->instr.map = 0;
-			else
-			    bad_value(param, param+3, arg);
-			break;
 		    case 't':
 			init->instr.mtrace = get_value(argv[i]+4, argv, &i);
 			break;
@@ -1817,9 +1801,7 @@ handle_args(int *argc, char **argv, erts_alc_hndl_args_init_t *init)
 	    case '-':
 		if (argv[i][2] == '\0') {
 		    /* End of system flags reached */
-		    if (init->instr.mtrace
-			/* || init->instr.stat
-			   || init->instr.map */) {
+		    if (init->instr.mtrace) {
 			while (i < *argc) {
 			    if(sys_strcmp(argv[i], "-sname") == 0
 			       || sys_strcmp(argv[i], "-name") == 0) {
@@ -2097,7 +2079,7 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
  * NOTE! When updating this function, make sure to also update
  *       erlang:memory/[0,1] in $ERL_TOP/erts/preloaded/src/erlang.erl
  */
-#define ERTS_MEM_NEED_ALL_ALCU (!erts_instr_stat && want_tot_or_sys)
+#define ERTS_MEM_NEED_ALL_ALCU (want_tot_or_sys)
     struct {
 	int total;
 	int processes;
@@ -2108,7 +2090,6 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
 	int binary;
 	int code;
 	int ets;
-	int maximum;
     } want = {0};
     struct {
 	UWord total;
@@ -2120,7 +2101,6 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
 	UWord binary;
 	UWord code;
 	UWord ets;
-	UWord maximum;
     } size = {0};
     Eterm atoms[sizeof(size)/sizeof(UWord)];
     UWord *uintps[sizeof(size)/sizeof(UWord)];
@@ -2173,12 +2153,6 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
 	want.ets = 1;
 	atoms[length] = am_ets;
 	uintps[length++] = &size.ets;
-
-	want.maximum = erts_instr_stat;
-	if (want.maximum) {
-	    atoms[length] = am_maximum;
-	    uintps[length++] = &size.maximum;
-	}
     }
     else {
 	DeclareTmpHeapNoproc(tmp_heap,2);
@@ -2260,18 +2234,6 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
 		    uintps[length++] = &size.ets;
 		}
 		break;
-	    case am_maximum:
-		if (erts_instr_stat) {
-		    if (!want.maximum) {
-			want.maximum = 1;
-			atoms[length] = am_maximum;
-			uintps[length++] = &size.maximum;
-		    }
-		} else {
-		    UnUseTmpHeapNoproc(2);
-		    return am_badarg;
-		}
-		break;
 	    default:
 		UnUseTmpHeapNoproc(2);
 		return am_badarg;
@@ -2437,14 +2399,7 @@ erts_memory(fmtfn_t *print_to_p, void *print_to_arg, void *proc, Eterm earg)
 	size.ets += erts_get_ets_misc_mem_size();
     }
 
-    if (erts_instr_stat && (want_tot_or_sys || want.maximum)) {
-	if (want_tot_or_sys) {
-	    size.total = erts_instr_get_total();
-	    size.system = size.total - size.processes;
-	}
-	size.maximum = erts_instr_get_max_total();
-    }
-    else if (want_tot_or_sys) {
+    if (want_tot_or_sys) {
 	size.system = size.total - size.processes;
     }
 
@@ -2522,18 +2477,6 @@ erts_allocated_areas(fmtfn_t *print_to_p, void *print_to_arg, void *proc)
 
     i = 0;
 
-    if (erts_instr_stat) {
-	values[i].arity = 2;
-	values[i].name = "total";
-	values[i].ui[0] = erts_instr_get_total();
-	i++;
-
-	values[i].arity = 2;
-	values[i].name = "maximum";
-	values[i].ui[0] = erts_instr_get_max_total();
-	i++;
-    }
-
     values[i].arity = 2;
     values[i].name = "sys_misc";
     values[i].ui[0] = erts_sys_misc_mem_sz();
@@ -2824,10 +2767,7 @@ erts_allocator_info(fmtfn_t to, void *arg)
     erts_alcu_au_info_options(&to, arg, NULL, NULL);
 
     erts_print(to, arg, "=allocator:instr\n");
-    erts_print(to, arg, "option m: %s\n",
-	       erts_instr_memory_map ? "true" : "false");
-    erts_print(to, arg, "option s: %s\n",
-	       erts_instr_stat ? "true" : "false");
+
     erts_print(to, arg, "option t: %s\n",
 	       erts_mtrace_enabled ? "true" : "false");
 
@@ -2933,16 +2873,12 @@ erts_allocator_options(void *proc)
                                              NULL, hpp, szp);
 #endif
     {
-	Eterm o[3], v[3];
-	o[0] = am_atom_put("m", 1);
-	v[0] = erts_instr_memory_map ? am_true : am_false;
-	o[1] = am_atom_put("s", 1);
-	v[1] = erts_instr_stat ? am_true : am_false;
-	o[2] = am_atom_put("t", 1);
-	v[2] = erts_mtrace_enabled ? am_true : am_false;
+	Eterm o[1], v[1];
+	o[0] = am_atom_put("t", 1);
+	v[0] = erts_mtrace_enabled ? am_true : am_false;
 
 	atoms[length] = am_atom_put("instr", 5); 
-	terms[length++] = erts_bld_2tup_list(hpp, szp, 3, o, v);
+	terms[length++] = erts_bld_2tup_list(hpp, szp, 1, o, v);
     }
 
     atoms[length] = am_atom_put("lock_physical_memory", 20);
@@ -3458,8 +3394,8 @@ badarg:
 
 /* 
  * The allocator wrapper prelocking stuff below is about the locking order.
- * It only affects wrappers (erl_mtrace.c and erl_instrument.c) that keep locks
- * during alloc/realloc/free.
+ * It only affects wrappers (erl_mtrace.c) that keep locks during
+ * alloc/realloc/free.
  *
  * Some query functions in erl_alloc_util.c lock the allocator mutex and then
  * use erts_printf that in turn may call the sys allocator through the wrappers.
diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c
index e148be7af6..fdf355d503 100644
--- a/erts/emulator/beam/erl_alloc_util.c
+++ b/erts/emulator/beam/erl_alloc_util.c
@@ -48,6 +48,8 @@
 #include "erl_mseg.h"
 #include "erl_threads.h"
 #include "erl_thr_progress.h"
+#include "erl_bif_unique.h"
+#include "erl_nif.h"
 
 #ifdef ERTS_ENABLE_LOCK_COUNT
 #include "erl_lock_count.h"
@@ -139,6 +141,33 @@ MBC after deallocating first block:
 [Carrier_t|pad|Block_t 111| udata... ]
 */
 
+/* Allocation tags ...
+ *
+ * These are added to the footer of every block when enabled. Currently they
+ * consist of the allocation type and an atom identifying the allocating
+ * driver/nif (or 'system' if that can't be determined), but the format is not
+ * supposed to be set in stone.
+ *
+ * The packing scheme requires that the atom values are small enough to fit
+ * into a word with ERTS_ALC_N_BITS to spare. Users must check for overflow
+ * before MAKE_ATAG(). */
+
+typedef UWord alcu_atag_t;
+
+#define MAKE_ATAG(IdAtom, Type) \
+    (ASSERT((Type) >= ERTS_ALC_N_MIN && (Type) <= ERTS_ALC_N_MAX), \
+     ASSERT(atom_val(IdAtom) <= MAX_ATAG_ATOM_ID), \
+     (atom_val(IdAtom) << ERTS_ALC_N_BITS) | (Type))
+
+#define ATAG_ID(AT) (make_atom((AT) >> ERTS_ALC_N_BITS))
+#define ATAG_TYPE(AT) ((AT) & ERTS_ALC_N_MASK)
+
+#define MAX_ATAG_ATOM_ID (ERTS_UWORD_MAX >> ERTS_ALC_N_BITS)
+
+#define DBG_IS_VALID_ATAG(Allocator, AT) \
+    (ATAG_TYPE(AT) >= ERTS_ALC_N_MIN && \
+     ATAG_TYPE(AT) <= ERTS_ALC_N_MAX && \
+     (Allocator)->alloc_no == ERTS_ALC_T2A(ERTS_ALC_N2T(ATAG_TYPE(AT))))
 
 /* Blocks ... */
 
@@ -153,10 +182,17 @@ MBC after deallocating first block:
 #endif
 #define FBLK_FTR_SZ (sizeof(FreeBlkFtr_t))
 
+#define GET_BLK_ATAG(B) \
+    (((alcu_atag_t *) (((char *) (B)) + (BLK_SZ(B))))[-1])
+#define SET_BLK_ATAG(B, T) \
+    (((alcu_atag_t *) (((char *) (B)) + (BLK_SZ(B))))[-1] = (T))
+
+#define BLK_ATAG_SZ(AP) ((AP)->atags ? sizeof(alcu_atag_t) : 0)
+
 #define UMEMSZ2BLKSZ(AP, SZ)						\
-  (ABLK_HDR_SZ + (SZ) <= (AP)->min_block_size				\
+  (ABLK_HDR_SZ + BLK_ATAG_SZ(AP) + (SZ) <= (AP)->min_block_size		\
    ? (AP)->min_block_size						\
-   : UNIT_CEILING(ABLK_HDR_SZ + (SZ)))
+   : UNIT_CEILING(ABLK_HDR_SZ + BLK_ATAG_SZ(AP) + (SZ)))
 
 #define UMEM2BLK(P) ((Block_t *) (((char *) (P)) - ABLK_HDR_SZ))
 #define BLK2UMEM(P) ((void *)    (((char *) (P)) + ABLK_HDR_SZ))
@@ -688,6 +724,62 @@ static void destroy_carrier(Allctr_t *, Block_t *, Carrier_t **);
 static void mbc_free(Allctr_t *allctr, void *p, Carrier_t **busy_pcrr_pp);
 static void dealloc_block(Allctr_t *, void *, ErtsAlcFixList_t *, int);
 
+static alcu_atag_t determine_alloc_tag(Allctr_t *allocator, ErtsAlcType_t type)
+{
+    ErtsSchedulerData *esdp;
+    Eterm id;
+
+    ERTS_CT_ASSERT(_unchecked_atom_val(am_system) <= MAX_ATAG_ATOM_ID);
+    ASSERT(allocator->atags);
+
+    esdp = erts_get_scheduler_data();
+    id = am_system;
+
+    if (esdp) {
+        if (esdp->current_nif) {
+            Module *mod = erts_nif_get_module((esdp->current_nif)->mod_nif);
+
+            /* Mod can be NULL if a resource destructor allocates memory after
+             * the module has been unloaded. */
+            if (mod) {
+                id = make_atom(mod->module);
+            }
+        } else if (esdp->current_port) {
+            Port *p = esdp->current_port;
+            id = (p->drv_ptr)->name_atom;
+        }
+
+        /* We fall back to 'system' if we can't pack the driver/NIF name into
+         * the tag. This may be a bit misleading but we've made no promises
+         * that the information is complete.
+         *
+         * This can only happen on 32-bit emulators when a new driver/NIF has
+         * been loaded *after* 16 million atoms have been used, and supporting
+         * that fringe case is not worth an extra word. 64-bit emulators are
+         * unaffected since the atom cache limits atom indexes to 32 bits. */
+        if(MAX_ATOM_TABLE_SIZE > MAX_ATAG_ATOM_ID) {
+            if (atom_val(id) > MAX_ATAG_ATOM_ID) {
+                id = am_system;
+            }
+        }
+    }
+
+    return MAKE_ATAG(id, type);
+}
+
+static void set_alloc_tag(Allctr_t *allocator, void *p, alcu_atag_t tag)
+{
+    Block_t *block;
+
+    ASSERT(DBG_IS_VALID_ATAG(allocator, tag));
+    ASSERT(allocator->atags && p);
+    (void)allocator;
+
+    block = UMEM2BLK(p);
+
+    SET_BLK_ATAG(block, tag);
+}
+
 /* internal data... */
 
 #if 0
@@ -4242,6 +4334,7 @@ static struct {
     Eterm e;
     Eterm t;
     Eterm ramv;
+    Eterm atags;
 #if HAVE_ERTS_MSEG
     Eterm asbcst;
     Eterm rsbcst;
@@ -4311,7 +4404,7 @@ static struct {
 #endif
 } am;
 
-static Eterm fix_type_atoms[ERTS_ALC_NO_FIXED_SIZES];
+static Eterm alloc_type_atoms[ERTS_ALC_N_MAX + 1];
 
 static ERTS_INLINE void atom_init(Eterm *atom, char *name)
 {
@@ -4342,6 +4435,7 @@ init_atoms(Allctr_t *allctr)
 	AM_INIT(e);
 	AM_INIT(t);
 	AM_INIT(ramv);
+	AM_INIT(atags);
 #if HAVE_ERTS_MSEG
 	AM_INIT(asbcst);
 	AM_INIT(rsbcst);
@@ -4413,12 +4507,12 @@ init_atoms(Allctr_t *allctr)
 	}
 #endif
 
-	for (ix = 0; ix < ERTS_ALC_NO_FIXED_SIZES; ix++) {
-	    ErtsAlcType_t n = ERTS_ALC_N_MIN_A_FIXED_SIZE + ix;
-	    char *name = (char *) ERTS_ALC_N2TD(n);
-	    size_t len = sys_strlen(name);
-	    fix_type_atoms[ix] = am_atom_put(name, len);
-	}
+        for (ix = ERTS_ALC_N_MIN; ix <= ERTS_ALC_N_MAX; ix++) {
+            const char *name = ERTS_ALC_N2TD(ix);
+            size_t len = sys_strlen(name);
+
+            alloc_type_atoms[ix] = am_atom_put(name, len);
+        }
     }
     
     if (allctr && !allctr->atoms_initialized) {
@@ -4531,6 +4625,7 @@ sz_info_fix(Allctr_t *allctr,
 		ErtsAlcFixList_t *fix = &allctr->fix[ix];
 		UWord alloced = fix->type_size * fix->u.cpool.allocated;
 		UWord used = fix->type_size * fix->u.cpool.used;
+                ErtsAlcType_t n = ERTS_ALC_N_MIN_A_FIXED_SIZE + ix;
 
 		if (print_to_p) {
 		    fmtfn_t to = *print_to_p;
@@ -4538,15 +4633,14 @@ sz_info_fix(Allctr_t *allctr,
 		    erts_print(to,
 			       arg,
 			       "fix type internal: %s %bpu %bpu\n",
-			       (char *) ERTS_ALC_N2TD(ERTS_ALC_N_MIN_A_FIXED_SIZE
-						      + ix),
+			       (char *) ERTS_ALC_N2TD(n),
 			       alloced,
 			       used);
 		}
 
 		if (hpp || szp) {
 		    add_3tup(hpp, szp, &res,
-			     fix_type_atoms[ix],
+			     alloc_type_atoms[n],
 			     bld_unstable_uint(hpp, szp, alloced),
 			     bld_unstable_uint(hpp, szp, used));
 		}
@@ -4559,6 +4653,7 @@ sz_info_fix(Allctr_t *allctr,
 	    ErtsAlcFixList_t *fix = &allctr->fix[ix];
 	    UWord alloced = fix->type_size * fix->u.nocpool.allocated;
 	    UWord used = fix->type_size*fix->u.nocpool.used;
+            ErtsAlcType_t n = ERTS_ALC_N_MIN_A_FIXED_SIZE + ix;
 
 	    if (print_to_p) {
 		fmtfn_t to = *print_to_p;
@@ -4566,15 +4661,14 @@ sz_info_fix(Allctr_t *allctr,
 		erts_print(to,
 			   arg,
 			   "fix type: %s %bpu %bpu\n",
-			   (char *) ERTS_ALC_N2TD(ERTS_ALC_N_MIN_A_FIXED_SIZE
-						  + ix),
+			   (char *) ERTS_ALC_N2TD(n),
 			   alloced,
 			   used);
 	    }
 
 	    if (hpp || szp) {
 		add_3tup(hpp, szp, &res,
-			 fix_type_atoms[ix],
+			 alloc_type_atoms[n],
 			 bld_unstable_uint(hpp, szp, alloced),
 			 bld_unstable_uint(hpp, szp, used));
 	    }
@@ -5000,6 +5094,7 @@ info_options(Allctr_t *allctr,
 		   "option e: true\n"
 		   "option t: %s\n"
 		   "option ramv: %s\n"
+		   "option atags: %s\n"
 		   "option sbct: %beu\n"
 #if HAVE_ERTS_MSEG
 		   "option asbcst: %bpu\n"
@@ -5018,6 +5113,7 @@ info_options(Allctr_t *allctr,
 		   "option acul: %bpu\n",
 		   topt,
 		   allctr->ramv ? "true" : "false",
+		   allctr->atags ? "true" : "false",
 		   allctr->sbc_threshold,
 #if HAVE_ERTS_MSEG
 		   allctr->mseg_opt.abs_shrink_th,
@@ -5087,6 +5183,7 @@ info_options(Allctr_t *allctr,
 		 am_sbct,
 		 bld_uint(hpp, szp, allctr->sbc_threshold));
 	add_2tup(hpp, szp, &res, am.ramv, allctr->ramv ? am_true : am_false);
+	add_2tup(hpp, szp, &res, am.atags, allctr->atags ? am_true : am_false);
 	add_2tup(hpp, szp, &res, am.t, (allctr->t ? am_true : am_false));
 	add_2tup(hpp, szp, &res, am.e, am_true);
     }
@@ -5408,9 +5505,8 @@ erts_alcu_current_size(Allctr_t *allctr, AllctrSize_t *size, ErtsAlcUFixInfo_t *
 /* ----------------------------------------------------------------------- */
 
 static ERTS_INLINE void *
-do_erts_alcu_alloc(ErtsAlcType_t type, void *extra, Uint size)
+do_erts_alcu_alloc(ErtsAlcType_t type, Allctr_t *allctr, Uint size)
 {
-    Allctr_t *allctr = (Allctr_t *) extra; 
     void *res;
 
     ASSERT(initialized);
@@ -5449,10 +5545,19 @@ do_erts_alcu_alloc(ErtsAlcType_t type, void *extra, Uint size)
 
 void *erts_alcu_alloc(ErtsAlcType_t type, void *extra, Uint size)
 {
+    Allctr_t *allctr = (Allctr_t *) extra;
     void *res;
+
     ASSERT(!"This is not thread safe");
-    res = do_erts_alcu_alloc(type, extra, size);
+
+    res = do_erts_alcu_alloc(type, allctr, size);
+
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, determine_alloc_tag(allctr, type));
+    }
+
     DEBUG_CHECK_ALIGNMENT(res);
+
     return res;
 }
 
@@ -5462,13 +5567,25 @@ void *
 erts_alcu_alloc_ts(ErtsAlcType_t type, void *extra, Uint size)
 {
     Allctr_t *allctr = (Allctr_t *) extra;
+    alcu_atag_t tag = 0;
     void *res;
+
+    if (allctr->atags) {
+        tag = determine_alloc_tag(allctr, type);
+    }
+
     erts_mtx_lock(&allctr->mutex);
-    res = do_erts_alcu_alloc(type, extra, size);
 
-    DEBUG_CHECK_ALIGNMENT(res);
+    res = do_erts_alcu_alloc(type, allctr, size);
+
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, tag);
+    }
 
     erts_mtx_unlock(&allctr->mutex);
+
+    DEBUG_CHECK_ALIGNMENT(res);
+
     return res;
 }
 
@@ -5478,6 +5595,7 @@ erts_alcu_alloc_thr_spec(ErtsAlcType_t type, void *extra, Uint size)
 {
     ErtsAllocatorThrSpec_t *tspec = (ErtsAllocatorThrSpec_t *) extra;
     int ix;
+    alcu_atag_t tag = 0;
     Allctr_t *allctr;
     void *res;
 
@@ -5487,11 +5605,19 @@ erts_alcu_alloc_thr_spec(ErtsAlcType_t type, void *extra, Uint size)
 
     allctr = tspec->allctr[ix];
 
+    if (allctr->atags) {
+        tag = determine_alloc_tag(allctr, type);
+    }
+
     if (allctr->thread_safe)
 	erts_mtx_lock(&allctr->mutex);
 
     res = do_erts_alcu_alloc(type, allctr, size);
 
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, tag);
+    }
+
     if (allctr->thread_safe)
 	erts_mtx_unlock(&allctr->mutex);
 
@@ -5504,10 +5630,15 @@ void *
 erts_alcu_alloc_thr_pref(ErtsAlcType_t type, void *extra, Uint size)
 {
     Allctr_t *pref_allctr;
+    alcu_atag_t tag = 0;
     void *res;
 
     pref_allctr = get_pref_allctr(extra);
 
+    if (pref_allctr->atags) {
+        tag = determine_alloc_tag(pref_allctr, type);
+    }
+
     if (pref_allctr->thread_safe)
 	erts_mtx_lock(&pref_allctr->mutex);
 
@@ -5523,12 +5654,15 @@ erts_alcu_alloc_thr_pref(ErtsAlcType_t type, void *extra, Uint size)
 	res = do_erts_alcu_alloc(type, pref_allctr, size);
     }
 
+    if (pref_allctr->atags && res) {
+        set_alloc_tag(pref_allctr, res, tag);
+    }
+
     if (pref_allctr->thread_safe)
 	erts_mtx_unlock(&pref_allctr->mutex);
 
     DEBUG_CHECK_ALIGNMENT(res);
 
-
     return res;
 }
 
@@ -5537,10 +5671,9 @@ erts_alcu_alloc_thr_pref(ErtsAlcType_t type, void *extra, Uint size)
 /* ------------------------------------------------------------------------- */
 
 static ERTS_INLINE void
-do_erts_alcu_free(ErtsAlcType_t type, void *extra, void *p,
+do_erts_alcu_free(ErtsAlcType_t type, Allctr_t *allctr, void *p,
 		  Carrier_t **busy_pcrr_pp)
 {
-    Allctr_t *allctr = (Allctr_t *) extra; 
     ASSERT(initialized);
 
     ASSERT(allctr);
@@ -5572,7 +5705,8 @@ do_erts_alcu_free(ErtsAlcType_t type, void *extra, void *p,
 
 void erts_alcu_free(ErtsAlcType_t type, void *extra, void *p)
 {
-    do_erts_alcu_free(type, extra, p, NULL);
+    Allctr_t *allctr = (Allctr_t *) extra;
+    do_erts_alcu_free(type, allctr, p, NULL);
 }
 
 
@@ -5581,7 +5715,7 @@ erts_alcu_free_ts(ErtsAlcType_t type, void *extra, void *p)
 {
     Allctr_t *allctr = (Allctr_t *) extra;
     erts_mtx_lock(&allctr->mutex);
-    do_erts_alcu_free(type, extra, p, NULL);
+    do_erts_alcu_free(type, allctr, p, NULL);
     erts_mtx_unlock(&allctr->mutex);
 }
 
@@ -5641,13 +5775,12 @@ erts_alcu_free_thr_pref(ErtsAlcType_t type, void *extra, void *p)
 
 static ERTS_INLINE void *
 do_erts_alcu_realloc(ErtsAlcType_t type,
-		     void *extra,
+		     Allctr_t *allctr,
 		     void *p,
 		     Uint size,
 		     Uint32 alcu_flgs,
 		     Carrier_t **busy_pcrr_pp)
 {
-    Allctr_t *allctr = (Allctr_t *) extra; 
     Block_t *blk;
     void *res;
 
@@ -5661,7 +5794,7 @@ do_erts_alcu_realloc(ErtsAlcType_t type,
     ERTS_ALCU_DBG_CHK_THR_ACCESS(allctr);
 
     if (!p) {
-	res = do_erts_alcu_alloc(type, extra, size);
+	res = do_erts_alcu_alloc(type, allctr, size);
 	INC_CC(allctr->calls.this_realloc);
 	DEC_CC(allctr->calls.this_alloc);
 	return res;
@@ -5670,7 +5803,7 @@ do_erts_alcu_realloc(ErtsAlcType_t type,
 #if ALLOC_ZERO_EQ_NULL
     if (!size) {
 	ASSERT(p);
-	do_erts_alcu_free(type, extra, p, busy_pcrr_pp);
+	do_erts_alcu_free(type, allctr, p, busy_pcrr_pp);
 	INC_CC(allctr->calls.this_realloc);
 	DEC_CC(allctr->calls.this_free);
 	return NULL;
@@ -5755,19 +5888,29 @@ do_erts_alcu_realloc(ErtsAlcType_t type,
 void *
 erts_alcu_realloc(ErtsAlcType_t type, void *extra, void *p, Uint size)
 {
+    Allctr_t *allctr = (Allctr_t *)extra;
     void *res;
-    res = do_erts_alcu_realloc(type, extra, p, size, 0, NULL);
+
+    res = do_erts_alcu_realloc(type, allctr, p, size, 0, NULL);
+
     DEBUG_CHECK_ALIGNMENT(res);
+
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, determine_alloc_tag(allctr, type));
+    }
+
     return res;
 }
 
 void *
 erts_alcu_realloc_mv(ErtsAlcType_t type, void *extra, void *p, Uint size)
 {
+    Allctr_t *allctr = (Allctr_t *)extra;
     void *res;
-    res = do_erts_alcu_alloc(type, extra, size);
+
+    res = do_erts_alcu_alloc(type, allctr, size);
     if (!res)
-	res = erts_alcu_realloc(type, extra, p, size);
+        res = do_erts_alcu_realloc(type, allctr, p, size, 0, NULL);
     else {
 	Block_t *blk;
 	size_t cpy_size;
@@ -5777,23 +5920,42 @@ erts_alcu_realloc_mv(ErtsAlcType_t type, void *extra, void *p, Uint size)
 	if (cpy_size > size)
 	    cpy_size = size;
 	sys_memcpy(res, p, cpy_size);
-	do_erts_alcu_free(type, extra, p, NULL);
+	do_erts_alcu_free(type, allctr, p, NULL);
     }
+
     DEBUG_CHECK_ALIGNMENT(res);
+
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, determine_alloc_tag(allctr, type));
+    }
+
     return res;
 }
 
 
-
 void *
 erts_alcu_realloc_ts(ErtsAlcType_t type, void *extra, void *ptr, Uint size)
 {
     Allctr_t *allctr = (Allctr_t *) extra;
+    alcu_atag_t tag = 0;
     void *res;
+
+    if (allctr->atags) {
+        tag = determine_alloc_tag(allctr, type);
+    }
+
     erts_mtx_lock(&allctr->mutex);
-    res = do_erts_alcu_realloc(type, extra, ptr, size, 0, NULL);
+
+    res = do_erts_alcu_realloc(type, allctr, ptr, size, 0, NULL);
+
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, tag);
+    }
+
     erts_mtx_unlock(&allctr->mutex);
+
     DEBUG_CHECK_ALIGNMENT(res);
+
     return res;
 }
 
@@ -5801,11 +5963,17 @@ void *
 erts_alcu_realloc_mv_ts(ErtsAlcType_t type, void *extra, void *p, Uint size)
 {
     Allctr_t *allctr = (Allctr_t *) extra;
+    alcu_atag_t tag = 0;
     void *res;
+
+    if (allctr->atags) {
+        tag = determine_alloc_tag(allctr, type);
+    }
+
     erts_mtx_lock(&allctr->mutex);
-    res = do_erts_alcu_alloc(type, extra, size);
+    res = do_erts_alcu_alloc(type, allctr, size);
     if (!res)
-	res = erts_alcu_realloc_ts(type, extra, p, size);
+	res = do_erts_alcu_realloc(type, allctr, p, size, 0, NULL);
     else {
 	Block_t *blk;
 	size_t cpy_size;
@@ -5815,10 +5983,17 @@ erts_alcu_realloc_mv_ts(ErtsAlcType_t type, void *extra, void *p, Uint size)
 	if (cpy_size > size)
 	    cpy_size = size;
 	sys_memcpy(res, p, cpy_size);
-	do_erts_alcu_free(type, extra, p, NULL);
+	do_erts_alcu_free(type, allctr, p, NULL);
     }
+
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, tag);
+    }
+
     erts_mtx_unlock(&allctr->mutex);
+
     DEBUG_CHECK_ALIGNMENT(res);
+
     return res;
 }
 
@@ -5829,6 +6004,7 @@ erts_alcu_realloc_thr_spec(ErtsAlcType_t type, void *extra,
 {
     ErtsAllocatorThrSpec_t *tspec = (ErtsAllocatorThrSpec_t *) extra;
     int ix;
+    alcu_atag_t tag = 0;
     Allctr_t *allctr;
     void *res;
 
@@ -5838,11 +6014,19 @@ erts_alcu_realloc_thr_spec(ErtsAlcType_t type, void *extra,
 
     allctr = tspec->allctr[ix];
 
+    if (allctr->atags) {
+        tag = determine_alloc_tag(allctr, type);
+    }
+
     if (allctr->thread_safe)
 	erts_mtx_lock(&allctr->mutex);
 
     res = do_erts_alcu_realloc(type, allctr, ptr, size, 0, NULL);
 
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, tag);
+    }
+
     if (allctr->thread_safe)
 	erts_mtx_unlock(&allctr->mutex);
 
@@ -5857,6 +6041,7 @@ erts_alcu_realloc_mv_thr_spec(ErtsAlcType_t type, void *extra,
 {
     ErtsAllocatorThrSpec_t *tspec = (ErtsAllocatorThrSpec_t *) extra;
     int ix;
+    alcu_atag_t tag = 0;
     Allctr_t *allctr;
     void *res;
 
@@ -5866,14 +6051,16 @@ erts_alcu_realloc_mv_thr_spec(ErtsAlcType_t type, void *extra,
 
     allctr = tspec->allctr[ix];
 
+    if (allctr->atags) {
+        tag = determine_alloc_tag(allctr, type);
+    }
+
     if (allctr->thread_safe)
 	erts_mtx_lock(&allctr->mutex);
 
     res = do_erts_alcu_alloc(type, allctr, size);
     if (!res) {
-	if (allctr->thread_safe)
-	    erts_mtx_unlock(&allctr->mutex);
-	res = erts_alcu_realloc_thr_spec(type, allctr, ptr, size);
+        res = do_erts_alcu_realloc(type, allctr, ptr, size, 0, NULL);
     }
     else {
 	Block_t *blk;
@@ -5885,29 +6072,34 @@ erts_alcu_realloc_mv_thr_spec(ErtsAlcType_t type, void *extra,
 	    cpy_size = size;
 	sys_memcpy(res, ptr, cpy_size);
 	do_erts_alcu_free(type, allctr, ptr, NULL);
-	if (allctr->thread_safe)
-	    erts_mtx_unlock(&allctr->mutex);
     }
 
+    if (allctr->atags && res) {
+        set_alloc_tag(allctr, res, tag);
+    }
+
+    if (allctr->thread_safe)
+        erts_mtx_unlock(&allctr->mutex);
+
     DEBUG_CHECK_ALIGNMENT(res);
 
     return res;
 }
 
 static ERTS_INLINE void *
-realloc_thr_pref(ErtsAlcType_t type, void *extra, void *p, Uint size,
+realloc_thr_pref(ErtsAlcType_t type, Allctr_t *pref_allctr, void *p, Uint size,
 		 int force_move)
 {
     void *res;
-    Allctr_t *pref_allctr, *used_allctr;
+    Allctr_t *used_allctr;
     UWord old_user_size;
     Carrier_t *busy_pcrr_p;
+    alcu_atag_t tag = 0;
     int retried;
 
-    if (!p)
-	return erts_alcu_alloc_thr_pref(type, extra, size);
-
-    pref_allctr = get_pref_allctr(extra);
+    if (pref_allctr->atags) {
+        tag = determine_alloc_tag(pref_allctr, type);
+    }
 
     if (pref_allctr->thread_safe)
 	erts_mtx_lock(&pref_allctr->mutex);
@@ -5936,6 +6128,11 @@ restart:
 	    retried = 1;
 	    goto restart;
 	}
+
+        if (pref_allctr->atags && res) {
+            set_alloc_tag(pref_allctr, res, tag);
+        }
+
 	if (pref_allctr->thread_safe)
 	    erts_mtx_unlock(&pref_allctr->mutex);
     }
@@ -5944,6 +6141,9 @@ restart:
 	if (!res)
 	    goto unlock_ts_return;
 	else {
+            if (pref_allctr->atags) {
+                set_alloc_tag(pref_allctr, res, tag);
+            }
 
 	    DEBUG_CHECK_ALIGNMENT(res);
 
@@ -5974,20 +6174,34 @@ restart:
 	}
     }
 
+    DEBUG_CHECK_ALIGNMENT(res);
+
     return res;
 }
 
 void *
 erts_alcu_realloc_thr_pref(ErtsAlcType_t type, void *extra, void *p, Uint size)
 {
-    return realloc_thr_pref(type, extra, p, size, 0);
+    if (p) {
+        Allctr_t *pref_allctr = get_pref_allctr(extra);
+
+        return realloc_thr_pref(type, pref_allctr, p, size, 0);
+    }
+
+    return erts_alcu_alloc_thr_pref(type, extra, size);
 }
 
 void *
 erts_alcu_realloc_mv_thr_pref(ErtsAlcType_t type, void *extra,
 			      void *p, Uint size)
 {
-    return realloc_thr_pref(type, extra, p, size, 1);
+    if (p) {
+        Allctr_t *pref_allctr = get_pref_allctr(extra);
+
+        return realloc_thr_pref(type, pref_allctr, p, size, 1);
+    }
+
+    return erts_alcu_alloc_thr_pref(type, extra, size);
 }
 
 
@@ -6071,6 +6285,7 @@ erts_alcu_start(Allctr_t *allctr, AllctrInit_t *init)
 	allctr->t			= 0;
 
     allctr->ramv			= init->ramv;
+    allctr->atags                       = init->atags;
     allctr->main_carrier_size		= init->mmbcs;
 
 #if HAVE_ERTS_MSEG
@@ -6320,6 +6535,1072 @@ erts_alcu_init(AlcUInit_t *init)
     initialized = 1;
 }
 
+/* ------------------------------------------------------------------------- */
+
+/* Allocation histograms and carrier information is gathered by walking through
+ * all carriers associated with each allocator instance. This is done as
+ * aux_yield_work on the scheduler that owns each instance.
+ *
+ * Yielding is implemented by temporarily inserting a "dummy carrier" at the
+ * last position. It's permanently "busy" so it won't get picked up by someone
+ * else when in the carrier pool, and we never make the employer aware of it
+ * through callbacks so we can't accidentally allocate on it.
+ *
+ * Plain malloc/free is used to guarantee we won't allocate with the allocator
+ * we're scanning. */
+
+/* Yield between carriers once this many blocks have been processed. Note that
+ * a single carrier scan may exceed this figure. */
+#ifndef DEBUG
+    #define BLOCKSCAN_REDUCTIONS (8000)
+#else
+    #define BLOCKSCAN_REDUCTIONS (400)
+#endif
+
+/* Abort a single carrier scan after this many blocks to prevent really large
+ * MBCs from blocking forever. */
+#define BLOCKSCAN_BAILOUT_THRESHOLD (16000)
+
+typedef struct alcu_blockscan {
+    /* A per-scheduler list used when multiple scans have been queued. The
+     * current scanner will always run until completion/abort before moving on
+     * to the next. */
+    struct alcu_blockscan *scanner_queue;
+
+    Allctr_t *allocator;
+    Process *process;
+
+    int (*current_op)(struct alcu_blockscan *scanner);
+    int (*next_op)(struct alcu_blockscan *scanner);
+    int reductions;
+
+    ErtsAlcCPoolData_t *cpool_cursor;
+    CarrierList_t *current_clist;
+    Carrier_t *clist_cursor;
+    Carrier_t dummy_carrier;
+
+    /* Called if the process that started this job dies before we're done. */
+    void (*abort)(void *user_data);
+
+    /* Called on each carrier. The callback must return the number of blocks
+     * scanned to yield properly between carriers.
+     *
+     * Note that it's not possible to "yield back" into a carrier. */
+    int (*scan)(Allctr_t *, void *user_data, Carrier_t *);
+
+    /* Called when all carriers have been scanned. The callback may return
+     * non-zero to yield. */
+    int (*finish)(void *user_data);
+
+    void *user_data;
+} blockscan_t;
+
+static Carrier_t *blockscan_restore_clist_cursor(blockscan_t *state)
+{
+    Carrier_t *cursor = state->clist_cursor;
+
+    ASSERT(state->clist_cursor == (state->current_clist)->first ||
+           state->clist_cursor == &state->dummy_carrier);
+
+    if (cursor == &state->dummy_carrier) {
+        cursor = cursor->next;
+
+        unlink_carrier(state->current_clist, state->clist_cursor);
+    }
+
+    return cursor;
+}
+
+static void blockscan_save_clist_cursor(blockscan_t *state, Carrier_t *after)
+{
+    ASSERT(state->clist_cursor == (state->current_clist)->first ||
+           state->clist_cursor == &state->dummy_carrier);
+
+    state->clist_cursor = &state->dummy_carrier;
+
+    (state->clist_cursor)->next = after->next;
+    (state->clist_cursor)->prev = after;
+
+    relink_carrier(state->current_clist, state->clist_cursor);
+}
+
+static int blockscan_clist_yielding(blockscan_t *state)
+{
+    Carrier_t *cursor = blockscan_restore_clist_cursor(state);
+
+    if (ERTS_PROC_IS_EXITING(state->process)) {
+        return 0;
+    }
+
+    while (cursor) {
+        /* Skip dummy carriers inserted by another (concurrent) block scan.
+         * This can happen when scanning thread-safe allocators from multiple
+         * schedulers. */
+        if (CARRIER_SZ(cursor) > 0) {
+            int blocks_scanned = state->scan(state->allocator,
+                                             state->user_data,
+                                             cursor);
+
+            state->reductions -= blocks_scanned;
+
+            if (state->reductions <= 0) {
+                blockscan_save_clist_cursor(state, cursor);
+                return 1;
+            }
+        }
+
+        cursor = cursor->next;
+    }
+
+    return 0;
+}
+
+static ErtsAlcCPoolData_t *blockscan_restore_cpool_cursor(blockscan_t *state)
+{
+    ErtsAlcCPoolData_t *cursor;
+
+    cursor = cpool_aint2cpd(cpool_read(&(state->cpool_cursor)->next));
+
+    if (state->cpool_cursor == &state->dummy_carrier.cpool) {
+        cpool_delete(state->allocator, state->allocator, &state->dummy_carrier);
+    }
+
+    return cursor;
+}
+
+static void blockscan_save_cpool_cursor(blockscan_t *state,
+                                        ErtsAlcCPoolData_t *after)
+{
+    ErtsAlcCPoolData_t *dummy_carrier, *prev_carrier, *next_carrier;
+
+    dummy_carrier = &state->dummy_carrier.cpool;
+
+    next_carrier = cpool_aint2cpd(cpool_mod_mark(&after->next));
+    prev_carrier = cpool_aint2cpd(cpool_mod_mark(&next_carrier->prev));
+
+    cpool_init(&dummy_carrier->next, (erts_aint_t)next_carrier);
+    cpool_init(&dummy_carrier->prev, (erts_aint_t)prev_carrier);
+
+    cpool_set_mod_marked(&prev_carrier->next,
+                         (erts_aint_t)dummy_carrier,
+                         (erts_aint_t)next_carrier);
+    cpool_set_mod_marked(&next_carrier->prev,
+                         (erts_aint_t)dummy_carrier,
+                         (erts_aint_t)prev_carrier);
+
+    state->cpool_cursor = dummy_carrier;
+}
+
+static int blockscan_cpool_yielding(blockscan_t *state)
+{
+    ErtsAlcCPoolData_t *sentinel, *cursor;
+
+    sentinel = &carrier_pool[(state->allocator)->alloc_no].sentinel;
+    cursor = blockscan_restore_cpool_cursor(state);
+
+    if (ERTS_PROC_IS_EXITING(state->process)) {
+        return 0;
+    }
+
+    while (cursor != sentinel) {
+        Carrier_t *carrier;
+        erts_aint_t exp;
+
+        /* When a deallocation happens on a pooled carrier it will be routed to
+         * its owner, so the only way to be sure that it isn't modified while
+         * scanning is to skip all carriers that aren't ours. The deallocations
+         * deferred to us will get handled when we're done. */
+        while (cursor->orig_allctr != state->allocator) {
+            cursor = cpool_aint2cpd(cpool_read(&cursor->next));
+
+            if (cursor == sentinel) {
+                return 0;
+            }
+        }
+
+        carrier = ErtsContainerStruct(cursor, Carrier_t, cpool);
+        exp = erts_atomic_read_rb(&carrier->allctr);
+
+        if (exp & ERTS_CRR_ALCTR_FLG_IN_POOL) {
+            ASSERT(state->allocator == (Allctr_t*)(exp & ~ERTS_CRR_ALCTR_FLG_MASK));
+            ASSERT(!(exp & ERTS_CRR_ALCTR_FLG_BUSY));
+
+            if (erts_atomic_cmpxchg_acqb(&carrier->allctr,
+                                         exp | ERTS_CRR_ALCTR_FLG_BUSY,
+                                         exp) == exp) {
+                /* Skip dummy carriers inserted by another (concurrent) block
+                 * scan. This can happen when scanning thread-safe allocators
+                 * from multiple schedulers. */
+                if (CARRIER_SZ(carrier) > 0) {
+                    int blocks_scanned = state->scan(state->allocator,
+                                                     state->user_data,
+                                                     carrier);
+
+                    state->reductions -= blocks_scanned;
+
+                    if (state->reductions <= 0) {
+                        blockscan_save_cpool_cursor(state, cursor);
+                        erts_atomic_set_relb(&carrier->allctr, exp);
+
+                        return 1;
+                    }
+                }
+
+                erts_atomic_set_relb(&carrier->allctr, exp);
+            }
+        }
+
+        cursor = cpool_aint2cpd(cpool_read(&cursor->next));
+    }
+
+    return 0;
+}
+
+static int blockscan_yield_helper(blockscan_t *state,
+                                  int (*yielding_op)(blockscan_t*))
+{
+    /* Note that we don't check whether to abort here; only yielding_op knows
+     * whether the carrier is still in the list/pool. */
+
+    if ((state->allocator)->thread_safe) {
+        /* Locked scans have to be as short as possible. */
+        state->reductions = 1;
+
+        erts_mtx_lock(&(state->allocator)->mutex);
+    } else {
+        state->reductions = BLOCKSCAN_REDUCTIONS;
+    }
+
+    if (yielding_op(state)) {
+        state->next_op = state->current_op;
+    }
+
+    if ((state->allocator)->thread_safe) {
+        erts_mtx_unlock(&(state->allocator)->mutex);
+    }
+
+    return 1;
+}
+
+/* */
+
+static int blockscan_finish(blockscan_t *state)
+{
+    if (ERTS_PROC_IS_EXITING(state->process)) {
+        state->abort(state->user_data);
+        return 0;
+    }
+
+    state->current_op = blockscan_finish;
+
+    return state->finish(state->user_data);
+}
+
+static int blockscan_sweep_sbcs(blockscan_t *state)
+{
+    if (state->current_op != blockscan_sweep_sbcs) {
+        SET_CARRIER_HDR(&state->dummy_carrier, 0, SCH_SBC, state->allocator);
+        state->current_clist = &(state->allocator)->sbc_list;
+        state->clist_cursor = (state->current_clist)->first;
+    }
+
+    state->current_op = blockscan_sweep_sbcs;
+    state->next_op = blockscan_finish;
+
+    return blockscan_yield_helper(state, blockscan_clist_yielding);
+}
+
+static int blockscan_sweep_mbcs(blockscan_t *state)
+{
+    if (state->current_op != blockscan_sweep_mbcs) {
+        SET_CARRIER_HDR(&state->dummy_carrier, 0, SCH_MBC, state->allocator);
+        state->current_clist = &(state->allocator)->mbc_list;
+        state->clist_cursor = (state->current_clist)->first;
+    }
+
+    state->current_op = blockscan_sweep_mbcs;
+    state->next_op = blockscan_sweep_sbcs;
+
+    return blockscan_yield_helper(state, blockscan_clist_yielding);
+}
+
+static int blockscan_sweep_cpool(blockscan_t *state)
+{
+    if (state->current_op != blockscan_sweep_cpool) {
+        ErtsAlcCPoolData_t *sentinel;
+
+        SET_CARRIER_HDR(&state->dummy_carrier, 0, SCH_MBC, state->allocator);
+        sentinel = &carrier_pool[(state->allocator)->alloc_no].sentinel;
+        state->cpool_cursor = sentinel;
+    }
+
+    state->current_op = blockscan_sweep_cpool;
+    state->next_op = blockscan_sweep_mbcs;
+
+    return blockscan_yield_helper(state, blockscan_cpool_yielding);
+}
+
+static int blockscan_get_specific_allocator(int allocator_num,
+                                            int sched_id,
+                                            Allctr_t **out)
+{
+    ErtsAllocatorInfo_t *ai;
+    Allctr_t *allocator;
+
+    ASSERT(allocator_num >= ERTS_ALC_A_MIN &&
+           allocator_num <= ERTS_ALC_A_MAX);
+    ASSERT(sched_id >= 0 && sched_id <= erts_no_schedulers);
+
+    ai = &erts_allctrs_info[allocator_num];
+
+    if (!ai->enabled || !ai->alloc_util) {
+        return 0;
+    }
+
+    if (!ai->thr_spec) {
+        if (sched_id != 0) {
+            /* Only thread-specific allocators can be scanned on a specific
+             * scheduler. */
+            return 0;
+        }
+
+        allocator = (Allctr_t*)ai->extra;
+        ASSERT(allocator->thread_safe);
+    } else {
+        ErtsAllocatorThrSpec_t *tspec = (ErtsAllocatorThrSpec_t*)ai->extra;
+
+        ASSERT(sched_id < tspec->size);
+
+        allocator = tspec->allctr[sched_id];
+    }
+
+    *out = allocator;
+
+    return 1;
+}
+
+static void blockscan_sched_trampoline(void *arg)
+{
+    ErtsAlcuBlockscanYieldData *yield;
+    ErtsSchedulerData *esdp;
+    blockscan_t *scanner;
+
+    esdp = erts_get_scheduler_data();
+    scanner = (blockscan_t*)arg;
+
+    yield = ERTS_SCHED_AUX_YIELD_DATA(esdp, alcu_blockscan);
+
+    ASSERT((yield->last == NULL) == (yield->current == NULL));
+
+    if (yield->last != NULL) {
+        blockscan_t *prev_scanner = yield->last;
+
+        ASSERT(prev_scanner->scanner_queue == NULL);
+
+        prev_scanner->scanner_queue = scanner;
+    } else {
+        yield->current = scanner;
+    }
+
+    scanner->scanner_queue = NULL;
+    yield->last = scanner;
+
+    erts_notify_new_aux_yield_work(esdp);
+}
+
+static void blockscan_dispatch(blockscan_t *scanner, Process *owner,
+                               Allctr_t *allocator, int sched_id)
+{
+    ASSERT(erts_get_scheduler_id() != 0);
+
+    if (sched_id == 0) {
+        /* Global instances are always handled on the current scheduler. */
+        sched_id = ERTS_ALC_GET_THR_IX();
+        ASSERT(allocator->thread_safe);
+    }
+
+    scanner->allocator = allocator;
+    scanner->process = owner;
+
+    erts_proc_inc_refc(scanner->process);
+
+    cpool_init_carrier_data(scanner->allocator, &scanner->dummy_carrier);
+    erts_atomic_init_nob(&(scanner->dummy_carrier).allctr,
+                         (erts_aint_t)allocator | ERTS_CRR_ALCTR_FLG_BUSY);
+
+    if (ERTS_ALC_IS_CPOOL_ENABLED(scanner->allocator)) {
+        scanner->next_op = blockscan_sweep_cpool;
+    } else {
+        scanner->next_op = blockscan_sweep_mbcs;
+    }
+
+    /* Aux yield jobs can only be set up while running on the scheduler that
+     * services them, so we move there before continuing.
+     *
+     * We can't drive the scan itself through this since the scheduler will
+     * always finish *all* misc aux work in one go which makes it impossible to
+     * yield. */
+    erts_schedule_misc_aux_work(sched_id, blockscan_sched_trampoline, scanner);
+}
+
+int erts_handle_yielded_alcu_blockscan(ErtsSchedulerData *esdp,
+                                       ErtsAlcuBlockscanYieldData *yield)
+{
+    blockscan_t *scanner = yield->current;
+
+    (void)esdp;
+
+    ASSERT((yield->last == NULL) == (yield->current == NULL));
+
+    if (scanner) {
+        if (scanner->next_op(scanner)) {
+            return 1;
+        }
+
+        ASSERT(ERTS_PROC_IS_EXITING(scanner->process) ||
+               scanner->current_op == blockscan_finish);
+
+        yield->current = scanner->scanner_queue;
+
+        if (yield->current == NULL) {
+            ASSERT(scanner == yield->last);
+            yield->last = NULL;
+        }
+
+        erts_proc_dec_refc(scanner->process);
+
+        /* Plain free is intentional. */
+        free(scanner);
+
+        return yield->current != NULL;
+    }
+
+    return 0;
+}
+
+void erts_alcu_sched_spec_data_init(ErtsSchedulerData *esdp)
+{
+    ErtsAlcuBlockscanYieldData *yield;
+
+    yield = ERTS_SCHED_AUX_YIELD_DATA(esdp, alcu_blockscan);
+
+    yield->current = NULL;
+    yield->last = NULL;
+}
+
+/* ------------------------------------------------------------------------- */
+
+static ERTS_INLINE int u64_log2(Uint64 v)
+{
+    static const int log2_tab64[64] = {
+        63,  0, 58,  1, 59, 47, 53,  2,
+        60, 39, 48, 27, 54, 33, 42,  3,
+        61, 51, 37, 40, 49, 18, 28, 20,
+        55, 30, 34, 11, 43, 14, 22,  4,
+        62, 57, 46, 52, 38, 26, 32, 41,
+        50, 36, 17, 19, 29, 10, 13, 21,
+        56, 45, 25, 31, 35, 16,  9, 12,
+        44, 24, 15,  8, 23,  7,  6,  5};
+
+    v |= v >> 1;
+    v |= v >> 2;
+    v |= v >> 4;
+    v |= v >> 8;
+    v |= v >> 16;
+    v |= v >> 32;
+
+    return log2_tab64[((Uint64)((v - (v >> 1))*0x07EDD5E59A4E28C2)) >> 58];
+}
+
+/* ------------------------------------------------------------------------- */
+
+typedef struct hist_tree__ {
+    struct hist_tree__ *parent;
+    struct hist_tree__ *left;
+    struct hist_tree__ *right;
+
+    int is_red;
+
+    alcu_atag_t tag;
+    UWord histogram[1];
+} hist_tree_t;
+
+#define ERTS_RBT_PREFIX hist_tree
+#define ERTS_RBT_T hist_tree_t
+#define ERTS_RBT_KEY_T UWord
+#define ERTS_RBT_FLAGS_T int
+#define ERTS_RBT_INIT_EMPTY_TNODE(T) ((void)0)
+#define ERTS_RBT_IS_RED(T) ((T)->is_red)
+#define ERTS_RBT_SET_RED(T) ((T)->is_red = 1)
+#define ERTS_RBT_IS_BLACK(T) (!ERTS_RBT_IS_RED(T))
+#define ERTS_RBT_SET_BLACK(T) ((T)->is_red = 0)
+#define ERTS_RBT_GET_FLAGS(T) ((T)->is_red)
+#define ERTS_RBT_SET_FLAGS(T, F) ((T)->is_red = F)
+#define ERTS_RBT_GET_PARENT(T) ((T)->parent)
+#define ERTS_RBT_SET_PARENT(T, P) ((T)->parent = P)
+#define ERTS_RBT_GET_RIGHT(T) ((T)->right)
+#define ERTS_RBT_SET_RIGHT(T, R) ((T)->right = (R))
+#define ERTS_RBT_GET_LEFT(T) ((T)->left)
+#define ERTS_RBT_SET_LEFT(T, L) ((T)->left = (L))
+#define ERTS_RBT_GET_KEY(T) ((T)->tag)
+#define ERTS_RBT_IS_LT(KX, KY) (KX < KY)
+#define ERTS_RBT_IS_EQ(KX, KY) (KX == KY)
+#define ERTS_RBT_WANT_FOREACH_DESTROY_YIELDING
+#define ERTS_RBT_WANT_FOREACH_DESTROY
+#define ERTS_RBT_WANT_INSERT
+#define ERTS_RBT_WANT_LOOKUP
+#define ERTS_RBT_UNDEF
+
+#include "erl_rbtree.h"
+
+typedef struct {
+    blockscan_t common;
+
+    ErtsIRefStorage iref;
+    Process *process;
+
+    hist_tree_rbt_yield_state_t hist_tree_yield;
+    hist_tree_t *hist_tree;
+    UWord hist_count;
+
+    UWord hist_slot_start;
+    int hist_slot_count;
+
+    UWord unscanned_size;
+
+    ErtsHeapFactory msg_factory;
+    int building_result;
+    Eterm result_list;
+} gather_ahist_t;
+
+static void gather_ahist_update(gather_ahist_t *state, UWord tag, UWord size)
+{
+    hist_tree_t *hist_node;
+    UWord size_interval;
+    int hist_slot;
+
+    hist_node = hist_tree_rbt_lookup(state->hist_tree, tag);
+
+    if (hist_node == NULL) {
+        /* Plain calloc is intentional. */
+        hist_node = (hist_tree_t*)calloc(1, sizeof(hist_tree_t) +
+                                            (state->hist_slot_count - 1) *
+                                            sizeof(hist_node->histogram[0]));
+        hist_node->tag = tag;
+
+        hist_tree_rbt_insert(&state->hist_tree, hist_node);
+        state->hist_count++;
+    }
+
+    size_interval = (size / state->hist_slot_start);
+    size_interval = u64_log2(size_interval + 1);
+
+    hist_slot = MIN(size_interval, state->hist_slot_count - 1);
+
+    hist_node->histogram[hist_slot]++;
+}
+
+static int gather_ahist_scan(Allctr_t *allocator,
+                             void *user_data,
+                             Carrier_t *carrier)
+{
+    gather_ahist_t *state;
+    int blocks_scanned;
+    Block_t *block;
+
+    state = (gather_ahist_t*)user_data;
+    blocks_scanned = 1;
+
+    if (IS_SB_CARRIER(carrier)) {
+        alcu_atag_t tag;
+
+        block = SBC2BLK(allocator, carrier);
+        tag = GET_BLK_ATAG(block);
+
+        ASSERT(DBG_IS_VALID_ATAG(allocator, tag));
+
+        gather_ahist_update(state, tag, SBC_BLK_SZ(block));
+    } else {
+        UWord scanned_bytes = MBC_HEADER_SIZE(allocator);
+
+        ASSERT(IS_MB_CARRIER(carrier));
+
+        block = MBC_TO_FIRST_BLK(allocator, carrier);
+
+        while (1) {
+            UWord block_size = MBC_BLK_SZ(block);
+
+            if (IS_ALLOCED_BLK(block)) {
+                alcu_atag_t tag = GET_BLK_ATAG(block);
+
+                ASSERT(DBG_IS_VALID_ATAG(allocator, tag));
+
+                gather_ahist_update(state, tag, block_size);
+            }
+
+            scanned_bytes += block_size;
+
+            if (blocks_scanned >= BLOCKSCAN_BAILOUT_THRESHOLD) {
+                state->unscanned_size += CARRIER_SZ(carrier) - scanned_bytes;
+                break;
+            } else if (IS_LAST_BLK(block)) {
+                break;
+            }
+
+            block = NXT_BLK(block);
+            blocks_scanned++;
+        }
+    }
+
+    return blocks_scanned;
+}
+
+static void gather_ahist_append_result(hist_tree_t *node, void *arg)
+{
+    gather_ahist_t *state = (gather_ahist_t*)arg;
+
+    Eterm histogram_tuple, tag_tuple;
+
+    Eterm *hp;
+    int ix;
+
+    ASSERT(state->building_result);
+
+    hp = erts_produce_heap(&state->msg_factory, 7 + state->hist_slot_count, 0);
+
+    hp[0] = make_arityval(state->hist_slot_count);
+
+    for (ix = 0; ix < state->hist_slot_count; ix++) {
+        hp[1 + ix] = make_small(node->histogram[ix]);
+    }
+
+    histogram_tuple = make_tuple(hp);
+    hp += 1 + state->hist_slot_count;
+
+    hp[0] = make_arityval(3);
+    hp[1] = ATAG_ID(node->tag);
+    hp[2] = alloc_type_atoms[ATAG_TYPE(node->tag)];
+    hp[3] = histogram_tuple;
+
+    tag_tuple = make_tuple(hp);
+    hp += 4;
+
+    state->result_list = CONS(hp, tag_tuple, state->result_list);
+
+    /* Plain free is intentional. */
+    free(node);
+}
+
+static void gather_ahist_send(gather_ahist_t *state)
+{
+    Eterm result_tuple, unscanned_size, task_ref;
+
+    Uint term_size;
+    Eterm *hp;
+
+    ASSERT((state->result_list == NIL) ^ (state->hist_count > 0));
+    ASSERT(state->building_result);
+
+    term_size = 4 + erts_iref_storage_heap_size(&state->iref);
+    term_size += IS_USMALL(0, state->unscanned_size) ? 0 : BIG_UINT_HEAP_SIZE;
+
+    hp = erts_produce_heap(&state->msg_factory, term_size, 0);
+
+    task_ref = erts_iref_storage_make_ref(&state->iref, &hp,
+        &(state->msg_factory.message)->hfrag.off_heap, 0);
+
+    unscanned_size = bld_unstable_uint(&hp, NULL, state->unscanned_size);
+
+    hp[0] = make_arityval(3);
+    hp[1] = task_ref;
+    hp[2] = unscanned_size;
+    hp[3] = state->result_list;
+
+    result_tuple = make_tuple(hp);
+
+    erts_factory_trim_and_close(&state->msg_factory, &result_tuple, 1);
+
+    erts_queue_message(state->process, 0, state->msg_factory.message,
+                       result_tuple, am_system);
+}
+
+static int gather_ahist_finish(void *arg)
+{
+    gather_ahist_t *state = (gather_ahist_t*)arg;
+
+    if (!state->building_result) {
+        ErtsMessage *message;
+        Uint minimum_size;
+        Eterm *hp;
+
+        /* {Ref, unscanned size, [{Tag, {Histogram}} | Rest]} */
+        minimum_size = 4 + erts_iref_storage_heap_size(&state->iref) +
+                       state->hist_count * (7 + state->hist_slot_count);
+
+        message = erts_alloc_message(minimum_size, &hp);
+        erts_factory_selfcontained_message_init(&state->msg_factory,
+                                                message, hp);
+
+        ERTS_RBT_YIELD_STAT_INIT(&state->hist_tree_yield);
+
+        state->result_list = NIL;
+        state->building_result = 1;
+    }
+
+    if (hist_tree_rbt_foreach_destroy_yielding(&state->hist_tree,
+                                               &gather_ahist_append_result,
+                                               state,
+                                               &state->hist_tree_yield,
+                                               BLOCKSCAN_REDUCTIONS)) {
+        return 1;
+    }
+
+    gather_ahist_send(state);
+
+    return 0;
+}
+
+static void gather_ahist_destroy_result(hist_tree_t *node, void *arg)
+{
+    (void)arg;
+    free(node);
+}
+
+static void gather_ahist_abort(void *arg)
+{
+    gather_ahist_t *state = (gather_ahist_t*)arg;
+
+    if (state->building_result) {
+        erts_factory_undo(&state->msg_factory);
+    }
+
+    hist_tree_rbt_foreach_destroy(&state->hist_tree,
+                                  &gather_ahist_destroy_result,
+                                  NULL);
+}
+
+int erts_alcu_gather_alloc_histograms(Process *p, int allocator_num,
+                                      int sched_id, int hist_width,
+                                      UWord hist_start, Eterm ref)
+{
+    gather_ahist_t *gather_state;
+    blockscan_t *scanner;
+    Allctr_t *allocator;
+
+    ASSERT(is_internal_ref(ref));
+
+    if (!blockscan_get_specific_allocator(allocator_num,
+                                          sched_id,
+                                          &allocator)) {
+        return 0;
+    } else if (!allocator->atags) {
+        return 0;
+    }
+
+    ensure_atoms_initialized(allocator);
+
+    /* Plain calloc is intentional. */
+    gather_state = (gather_ahist_t*)calloc(1, sizeof(gather_ahist_t));
+    scanner = &gather_state->common;
+
+    scanner->abort = gather_ahist_abort;
+    scanner->scan = gather_ahist_scan;
+    scanner->finish = gather_ahist_finish;
+    scanner->user_data = gather_state;
+
+    erts_iref_storage_save(&gather_state->iref, ref);
+    gather_state->hist_slot_start = hist_start;
+    gather_state->hist_slot_count = hist_width;
+    gather_state->process = p;
+
+    blockscan_dispatch(scanner, p, allocator, sched_id);
+
+    return 1;
+}
+
+/* ------------------------------------------------------------------------- */
+
+typedef struct chist_node__ {
+    struct chist_node__ *next;
+
+    UWord carrier_size;
+    UWord unscanned_size;
+    UWord allocated_size;
+
+    /* BLOCKSCAN_BAILOUT_THRESHOLD guarantees we won't overflow this or the
+     * counters in the free block histogram. */
+    int allocated_count;
+    int flags;
+
+    int histogram[1];
+} chist_node_t;
+
+typedef struct {
+    blockscan_t common;
+
+    ErtsIRefStorage iref;
+    Process *process;
+
+    Eterm allocator_desc;
+
+    chist_node_t *info_list;
+    UWord info_count;
+
+    UWord hist_slot_start;
+    int hist_slot_count;
+
+    ErtsHeapFactory msg_factory;
+    int building_result;
+    Eterm result_list;
+} gather_cinfo_t;
+
+static int gather_cinfo_scan(Allctr_t *allocator,
+                             void *user_data,
+                             Carrier_t *carrier)
+{
+    gather_cinfo_t *state;
+    chist_node_t *node;
+    int blocks_scanned;
+    Block_t *block;
+
+    state = (gather_cinfo_t*)user_data;
+    node = calloc(1, sizeof(chist_node_t) +
+                     (state->hist_slot_count - 1) *
+                     sizeof(node->histogram[0]));
+    blocks_scanned = 1;
+
+    /* ERTS_CRR_ALCTR_FLG_BUSY is ignored since we've set it ourselves and it
+     * would be misleading to include it. */
+    node->flags = erts_atomic_read_rb(&carrier->allctr) &
+                  (ERTS_CRR_ALCTR_FLG_MASK & ~ERTS_CRR_ALCTR_FLG_BUSY);
+    node->carrier_size = CARRIER_SZ(carrier);
+
+    if (IS_SB_CARRIER(carrier)) {
+        UWord block_size;
+
+        block = SBC2BLK(allocator, carrier);
+        block_size = SBC_BLK_SZ(block);
+
+        node->allocated_size = block_size;
+        node->allocated_count = 1;
+    } else {
+        UWord scanned_bytes = MBC_HEADER_SIZE(allocator);
+
+        block = MBC_TO_FIRST_BLK(allocator, carrier);
+
+        while (1) {
+            UWord block_size = MBC_BLK_SZ(block);
+
+            scanned_bytes += block_size;
+
+            if (IS_ALLOCED_BLK(block)) {
+                node->allocated_size += block_size;
+                node->allocated_count++;
+            } else {
+                UWord size_interval;
+                int hist_slot;
+
+                size_interval = (block_size / state->hist_slot_start);
+                size_interval = u64_log2(size_interval + 1);
+
+                hist_slot = MIN(size_interval, state->hist_slot_count - 1);
+
+                node->histogram[hist_slot]++;
+            }
+
+            if (blocks_scanned >= BLOCKSCAN_BAILOUT_THRESHOLD) {
+                node->unscanned_size += CARRIER_SZ(carrier) - scanned_bytes;
+                break;
+            } else if (IS_LAST_BLK(block)) {
+                break;
+            }
+
+            block = NXT_BLK(block);
+            blocks_scanned++;
+        }
+    }
+
+    node->next = state->info_list;
+    state->info_list = node;
+    state->info_count++;
+
+    return blocks_scanned;
+}
+
+static void gather_cinfo_append_result(gather_cinfo_t *state,
+                                       chist_node_t *info)
+{
+    Eterm carrier_size, unscanned_size, allocated_size;
+    Eterm histogram_tuple, carrier_tuple;
+
+    Uint term_size;
+    Eterm *hp;
+    int ix;
+
+    ASSERT(state->building_result);
+
+    term_size = 11 + state->hist_slot_count;
+    term_size += IS_USMALL(0, info->carrier_size) ? 0 : BIG_UINT_HEAP_SIZE;
+    term_size += IS_USMALL(0, info->unscanned_size) ? 0 : BIG_UINT_HEAP_SIZE;
+    term_size += IS_USMALL(0, info->allocated_size) ? 0 : BIG_UINT_HEAP_SIZE;
+
+    hp = erts_produce_heap(&state->msg_factory, term_size, 0);
+
+    hp[0] = make_arityval(state->hist_slot_count);
+
+    for (ix = 0; ix < state->hist_slot_count; ix++) {
+        hp[1 + ix] = make_small(info->histogram[ix]);
+    }
+
+    histogram_tuple = make_tuple(hp);
+    hp += 1 + state->hist_slot_count;
+
+    carrier_size = bld_unstable_uint(&hp, NULL, info->carrier_size);
+    unscanned_size = bld_unstable_uint(&hp, NULL, info->unscanned_size);
+    allocated_size = bld_unstable_uint(&hp, NULL, info->allocated_size);
+
+    hp[0] = make_arityval(7);
+    hp[1] = state->allocator_desc;
+    hp[2] = carrier_size;
+    hp[3] = unscanned_size;
+    hp[4] = allocated_size;
+    hp[5] = make_small(info->allocated_count);
+    hp[6] = (info->flags & ERTS_CRR_ALCTR_FLG_IN_POOL) ? am_true : am_false;
+    hp[7] = histogram_tuple;
+
+    carrier_tuple = make_tuple(hp);
+    hp += 8;
+
+    state->result_list = CONS(hp, carrier_tuple, state->result_list);
+
+    free(info);
+}
+
+static void gather_cinfo_send(gather_cinfo_t *state)
+{
+    Eterm result_tuple, task_ref;
+
+    int term_size;
+    Eterm *hp;
+
+    ASSERT((state->result_list == NIL) ^ (state->info_count > 0));
+    ASSERT(state->building_result);
+
+    term_size = 3 + erts_iref_storage_heap_size(&state->iref);
+    hp = erts_produce_heap(&state->msg_factory, term_size, 0);
+
+    task_ref = erts_iref_storage_make_ref(&state->iref, &hp,
+        &(state->msg_factory.message)->hfrag.off_heap, 0);
+
+    hp[0] = make_arityval(2);
+    hp[1] = task_ref;
+    hp[2] = state->result_list;
+
+    result_tuple = make_tuple(hp);
+
+    erts_factory_trim_and_close(&state->msg_factory, &result_tuple, 1);
+
+    erts_queue_message(state->process, 0, state->msg_factory.message,
+                       result_tuple, am_system);
+}
+
+static int gather_cinfo_finish(void *arg)
+{
+    gather_cinfo_t *state = (gather_cinfo_t*)arg;
+    int reductions = BLOCKSCAN_REDUCTIONS;
+
+    if (!state->building_result) {
+        ErtsMessage *message;
+        Uint minimum_size;
+        Eterm *hp;
+
+        /* {Ref, [{Carrier size, unscanned size, allocated size,
+         *         allocated block count, {Free block histogram}} | Rest]} */
+        minimum_size = 3 + erts_iref_storage_heap_size(&state->iref) +
+                       state->info_count * (11 + state->hist_slot_count);
+
+        message = erts_alloc_message(minimum_size, &hp);
+        erts_factory_selfcontained_message_init(&state->msg_factory,
+                                                message, hp);
+
+        state->result_list = NIL;
+        state->building_result = 1;
+    }
+
+    while (state->info_list) {
+        chist_node_t *current = state->info_list;
+        state->info_list = current->next;
+
+        gather_cinfo_append_result(state, current);
+
+        if (reductions-- <= 0) {
+            return 1;
+        }
+    }
+
+    gather_cinfo_send(state);
+
+    return 0;
+}
+
+static void gather_cinfo_abort(void *arg)
+{
+    gather_cinfo_t *state = (gather_cinfo_t*)arg;
+
+    if (state->building_result) {
+        erts_factory_undo(&state->msg_factory);
+    }
+
+    while (state->info_list) {
+        chist_node_t *current = state->info_list;
+        state->info_list = current->next;
+
+        free(current);
+    }
+}
+
+int erts_alcu_gather_carrier_info(struct process *p, int allocator_num,
+                                  int sched_id, int hist_width,
+                                  UWord hist_start, Eterm ref)
+{
+    gather_cinfo_t *gather_state;
+    blockscan_t *scanner;
+
+    const char *allocator_desc;
+    Allctr_t *allocator;
+
+    ASSERT(is_internal_ref(ref));
+
+    if (!blockscan_get_specific_allocator(allocator_num,
+                                          sched_id,
+                                          &allocator)) {
+        return 0;
+    }
+
+    allocator_desc = ERTS_ALC_A2AD(allocator_num);
+
+    /* Plain calloc is intentional. */
+    gather_state = (gather_cinfo_t*)calloc(1, sizeof(gather_cinfo_t));
+    scanner = &gather_state->common;
+
+    scanner->abort = gather_cinfo_abort;
+    scanner->scan = gather_cinfo_scan;
+    scanner->finish = gather_cinfo_finish;
+    scanner->user_data = gather_state;
+
+    gather_state->allocator_desc = erts_atom_put((byte *)allocator_desc,
+                                                 sys_strlen(allocator_desc),
+                                                 ERTS_ATOM_ENC_LATIN1, 1);
+    erts_iref_storage_save(&gather_state->iref, ref);
+    gather_state->hist_slot_start = hist_start * 2;
+    gather_state->hist_slot_count = hist_width;
+    gather_state->process = p;
+
+    blockscan_dispatch(scanner, p, allocator, sched_id);
+
+    return 1;
+}
+
 
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
  * NOTE:  erts_alcu_test() is only supposed to be used for testing.          *
@@ -6441,6 +7722,7 @@ erts_alcu_verify_unused_ts(Allctr_t *allctr)
     erts_mtx_unlock(&allctr->mutex);
 }
 
+
 #ifdef DEBUG
 int is_sbc_blk(Block_t* blk)
 {
diff --git a/erts/emulator/beam/erl_alloc_util.h b/erts/emulator/beam/erl_alloc_util.h
index 05c8a0db3b..ff4d10b206 100644
--- a/erts/emulator/beam/erl_alloc_util.h
+++ b/erts/emulator/beam/erl_alloc_util.h
@@ -50,6 +50,7 @@ typedef struct {
     int tspec;
     int tpref;
     int ramv;
+    int atags;
     UWord sbct;
     UWord asbcst;
     UWord rsbcst;
@@ -106,6 +107,7 @@ typedef struct {
     0,			/* (bool)   tspec:  thread specific              */\
     0,			/* (bool)   tpref:  thread preferred             */\
     0,			/* (bool)   ramv:   realloc always moves         */\
+    0,			/* (bool)   atags:  tagged allocations           */\
     512*1024,		/* (bytes)  sbct:   sbc threshold                */\
     2*1024*2024,	/* (amount) asbcst: abs sbc shrink threshold     */\
     20,			/* (%)      rsbcst: rel sbc shrink threshold     */\
@@ -142,6 +144,7 @@ typedef struct {
     0,			/* (bool)   tspec:  thread specific              */\
     0,			/* (bool)   tpref:  thread preferred             */\
     0,			/* (bool)   ramv:   realloc always moves         */\
+    0,			/* (bool)   atags:  tagged allocations           */\
     64*1024,		/* (bytes)  sbct:   sbc threshold                */\
     2*1024*2024,	/* (amount) asbcst: abs sbc shrink threshold     */\
     20,			/* (%)      rsbcst: rel sbc shrink threshold     */\
@@ -224,6 +227,36 @@ void erts_lcnt_update_allocator_locks(int enable);
 
 int erts_alcu_try_set_dyn_param(Allctr_t*, Eterm param, Uint value);
 
+/* Gathers per-tag allocation histograms from the given allocator number
+ * (ERTS_ALC_A_*) and scheduler id. An id of 0 means the global instance will
+ * be used.
+ *
+ * The results are sent to `p`, and it returns the number of messages to wait
+ * for. */
+int erts_alcu_gather_alloc_histograms(struct process *p, int allocator_num,
+                                      int sched_id, int hist_width,
+                                      UWord hist_start, Eterm ref);
+
+/* Gathers per-carrier info from the given allocator number (ERTS_ALC_A_*) and
+ * scheduler id. An id of 0 means the global instance will be used.
+ *
+ * The results are sent to `p`, and it returns the number of messages to wait
+ * for. */
+int erts_alcu_gather_carrier_info(struct process *p, int allocator_num,
+                                  int sched_id, int hist_width,
+                                  UWord hist_start, Eterm ref);
+
+struct alcu_blockscan;
+
+typedef struct {
+    struct alcu_blockscan *current;
+    struct alcu_blockscan *last;
+} ErtsAlcuBlockscanYieldData;
+
+int erts_handle_yielded_alcu_blockscan(struct ErtsSchedulerData_ *esdp,
+                                       ErtsAlcuBlockscanYieldData *yield);
+void erts_alcu_sched_spec_data_init(struct ErtsSchedulerData_ *esdp);
+
 #endif /* !ERL_ALLOC_UTIL__ */
 
 #if defined(GET_ERL_ALLOC_UTIL_IMPL) && !defined(ERL_ALLOC_UTIL_IMPL__)
@@ -548,6 +581,7 @@ struct Allctr_t_ {
     /* Options */
     int			t;
     int			ramv;
+    int                 atags;
     Uint		sbc_threshold;
     Uint		sbc_move_threshold;
     Uint		mbc_move_threshold;
@@ -684,6 +718,7 @@ struct Allctr_t_ {
 #endif
 };
 
+
 int	erts_alcu_start(Allctr_t *, AllctrInit_t *);
 void	erts_alcu_stop(Allctr_t *);
 
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 89e3d3f43e..8687aefd78 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -38,7 +38,7 @@
 #include "erl_message.h"
 #include "erl_binary.h"
 #include "erl_db.h"
-#include "erl_instrument.h"
+#include "erl_mtrace.h"
 #include "dist.h"
 #include "erl_gc.h"
 #include "erl_cpu_topology.h"
@@ -51,6 +51,7 @@
 #include "erl_ptab.h"
 #include "erl_time.h"
 #include "erl_proc_sig_queue.h"
+#include "erl_alloc_util.h"
 #ifdef HIPE
 #include "hipe_arch.h"
 #endif
@@ -2151,45 +2152,6 @@ info_1_tuple(Process* BIF_P,	/* Pointer to current process. */
 	    return make_small(sizeof(UWord));
 	}
 	goto badarg;
-    } else if (sel == am_allocated) {
-	if (arity == 2) {
-	    Eterm res = THE_NON_VALUE;
-	    char *buf;
-	    Sint len = is_string(*tp);
-	    if (len <= 0)
-		return res;
-	    buf = (char *) erts_alloc(ERTS_ALC_T_TMP, len+1);
-	    if (intlist_to_buf(*tp, buf, len) != len)
-		erts_exit(ERTS_ERROR_EXIT, "%s:%d: Internal error\n", __FILE__, __LINE__);
-	    buf[len] = '\0';
-	    res = erts_instr_dump_memory_map(buf) ? am_true : am_false;
-	    erts_free(ERTS_ALC_T_TMP, (void *) buf);
-	    if (is_non_value(res))
-		goto badarg;
-	    return res;
-	}
-	else if (arity == 3 && tp[0] == am_status) {
-	    if (is_atom(tp[1]))
-		return erts_instr_get_stat(BIF_P, tp[1], 1);
-	    else {
-		Eterm res = THE_NON_VALUE;
-		char *buf;
-		Sint len = is_string(tp[1]);
-		if (len <= 0)
-		    return res;
-		buf = (char *) erts_alloc(ERTS_ALC_T_TMP, len+1);
-		if (intlist_to_buf(tp[1], buf, len) != len)
-		    erts_exit(ERTS_ERROR_EXIT, "%s:%d: Internal error\n", __FILE__, __LINE__);
-		buf[len] = '\0';
-		res = erts_instr_dump_stat(buf, 1) ? am_true : am_false;
-		erts_free(ERTS_ALC_T_TMP, (void *) buf);
-		if (is_non_value(res))
-		    goto badarg;
-		return res;
-	    }
-	}
-	else
-	    goto badarg;
     } else if (sel == am_allocator) {
 	switch (arity) {
 	case 2:
@@ -2557,8 +2519,6 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
     } else if (BIF_ARG_1 == am_allocated_areas) {
 	res = erts_allocated_areas(NULL, NULL, BIF_P);
 	BIF_RET(res);
-    } else if (BIF_ARG_1 == am_allocated) {
-	BIF_RET(erts_instr_get_memory_map(BIF_P));
     } else if (BIF_ARG_1 == am_hipe_architecture) {
 #if defined(HIPE)
 	BIF_RET(hipe_arch_name);
@@ -2699,9 +2659,6 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 			       sizeof(ERLANG_ARCHITECTURE)-1,
 			       NIL));
     } 
-    else if (BIF_ARG_1 == am_memory_types) {
-	return erts_instr_get_type_info(BIF_P);
-    }
     else if (BIF_ARG_1 == am_os_type) {
 	BIF_RET(os_type_tuple);
     }
@@ -4737,6 +4694,55 @@ BIF_RETTYPE erts_debug_set_internal_state_2(BIF_ALIST_2)
     BIF_ERROR(BIF_P, BADARG);
 }
 
+static BIF_RETTYPE
+gather_histograms_helper(Process * c_p, Eterm arg_tuple,
+                         int gather(Process *, int, int, int, UWord, Eterm))
+{
+    SWord hist_start, hist_width, sched_id;
+    int msg_count, alloc_num;
+    Eterm *args;
+
+    /* This is an internal BIF, so the error checking is mostly left to erlang
+     * code. */
+
+    ASSERT(is_tuple_arity(arg_tuple, 5));
+    args = tuple_val(arg_tuple);
+
+    for (alloc_num = ERTS_ALC_A_MIN; alloc_num <= ERTS_ALC_A_MAX; alloc_num++) {
+        if(erts_is_atom_str(ERTS_ALC_A2AD(alloc_num), args[1], 0)) {
+            break;
+        }
+    }
+
+    if (alloc_num > ERTS_ALC_A_MAX) {
+        BIF_ERROR(c_p, BADARG);
+    }
+
+    sched_id = signed_val(args[2]);
+    hist_width = signed_val(args[3]);
+    hist_start = signed_val(args[4]);
+
+    if (sched_id < 0 || sched_id > erts_no_schedulers) {
+        BIF_ERROR(c_p, BADARG);
+    }
+
+    msg_count = gather(c_p, alloc_num, sched_id, hist_width, hist_start, args[5]);
+
+    BIF_RET(make_small(msg_count));
+}
+
+BIF_RETTYPE erts_internal_gather_alloc_histograms_1(BIF_ALIST_1)
+{
+    return gather_histograms_helper(BIF_P, BIF_ARG_1,
+                                    erts_alcu_gather_alloc_histograms);
+}
+
+BIF_RETTYPE erts_internal_gather_carrier_info_1(BIF_ALIST_1)
+{
+    return gather_histograms_helper(BIF_P, BIF_ARG_1,
+                                    erts_alcu_gather_carrier_info);
+}
+
 #ifdef ERTS_ENABLE_LOCK_COUNT
 
 typedef struct {
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 179822cc0b..57c6c10c7f 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -37,7 +37,7 @@
 #include "erl_mseg.h"
 #include "erl_threads.h"
 #include "erl_hl_timer.h"
-#include "erl_instrument.h"
+#include "erl_mtrace.h"
 #include "erl_printf_term.h"
 #include "erl_misc_utils.h"
 #include "packet_parser.h"
diff --git a/erts/emulator/beam/erl_instrument.c b/erts/emulator/beam/erl_instrument.c
deleted file mode 100644
index 2f70e7996e..0000000000
--- a/erts/emulator/beam/erl_instrument.c
+++ /dev/null
@@ -1,1257 +0,0 @@
-/*
- * %CopyrightBegin%
- *
- * Copyright Ericsson AB 2003-2016. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- * %CopyrightEnd%
- */
-
-#ifdef HAVE_CONFIG_H
-#  include "config.h"
-#endif
-
-#include "global.h"
-#include "big.h"
-#include "erl_instrument.h"
-#include "erl_threads.h"
-
-typedef union { long l; double d; } Align_t;
-
-typedef struct {
-    Uint size;
-#ifdef VALGRIND
-    void* valgrind_leak_suppressor;
-#endif
-    Align_t mem[1];
-} StatBlock_t;
-
-#define STAT_BLOCK_HEADER_SIZE (sizeof(StatBlock_t) - sizeof(Align_t))
-
-typedef struct MapStatBlock_t_ MapStatBlock_t;
-struct MapStatBlock_t_ {
-    Uint size;
-    ErtsAlcType_t type_no;
-    Eterm pid;
-    MapStatBlock_t *prev;
-    MapStatBlock_t *next;
-    Align_t mem[1];
-};
-
-#define MAP_STAT_BLOCK_HEADER_SIZE (sizeof(MapStatBlock_t) - sizeof(Align_t))
-
-typedef struct {
-    Uint size;
-    Uint max_size;
-    Uint max_size_ever;
-
-    Uint blocks;
-    Uint max_blocks;
-    Uint max_blocks_ever;
-} Stat_t;
-
-static erts_mtx_t instr_mutex;
-static erts_mtx_t instr_x_mutex;
-
-int erts_instr_memory_map;
-int erts_instr_stat;
-
-static ErtsAllocatorFunctions_t real_allctrs[ERTS_ALC_A_MAX+1];
-
-struct stats_ {
-    Stat_t tot;
-    Stat_t a[ERTS_ALC_A_MAX+1];
-    Stat_t *ap[ERTS_ALC_A_MAX+1];
-    Stat_t c[ERTS_ALC_C_MAX+1];
-    Stat_t n[ERTS_ALC_N_MAX+1];
-};
-
-static struct stats_ *stats;
-
-static MapStatBlock_t *mem_anchor;
-
-static Eterm *am_tot;
-static Eterm *am_n;
-static Eterm *am_a;
-static Eterm *am_c;
-
-static int atoms_initialized;
-
-static struct {
-    Eterm total;
-    Eterm allocators;
-    Eterm classes;
-    Eterm types;
-    Eterm sizes;
-    Eterm blocks;
-    Eterm instr_hdr;
-#ifdef DEBUG
-    Eterm end_of_atoms;
-#endif
-} am;
-
-static void ERTS_INLINE atom_init(Eterm *atom, const char *name)
-{
-    *atom = am_atom_put((char *) name, sys_strlen(name));
-}
-#define AM_INIT(AM) atom_init(&am.AM, #AM)
-
-static void
-init_atoms(void)
-{
-#ifdef DEBUG
-    Eterm *atom;
-    for (atom = (Eterm *) &am; atom <= &am.end_of_atoms; atom++) {
-	*atom = THE_NON_VALUE;
-    }
-#endif
-
-    AM_INIT(total);
-    AM_INIT(allocators);
-    AM_INIT(classes);
-    AM_INIT(types);
-    AM_INIT(sizes);
-    AM_INIT(blocks);
-    AM_INIT(instr_hdr);
-
-#ifdef DEBUG
-    for (atom = (Eterm *) &am; atom < &am.end_of_atoms; atom++) {
-	ASSERT(*atom != THE_NON_VALUE);
-    }
-#endif
-
-    atoms_initialized = 1;
-}
-
-#undef AM_INIT
-
-static void
-init_am_tot(void)
-{
-    am_tot = (Eterm *) erts_alloc(ERTS_ALC_T_INSTR_INFO,
-				  sizeof(Eterm));
-    atom_init(am_tot, "total");
-}
-
-
-static void
-init_am_n(void)
-{
-    int i;
-    am_n = (Eterm *) erts_alloc(ERTS_ALC_T_INSTR_INFO,
-				(ERTS_ALC_N_MAX+1)*sizeof(Eterm));
-
-    for (i = ERTS_ALC_N_MIN; i <= ERTS_ALC_N_MAX; i++) {
-	atom_init(&am_n[i], ERTS_ALC_N2TD(i));
-    }
-
-}
-
-static void
-init_am_c(void)
-{
-    int i;
-    am_c = (Eterm *) erts_alloc(ERTS_ALC_T_INSTR_INFO,
-				(ERTS_ALC_C_MAX+1)*sizeof(Eterm));
-
-    for (i = ERTS_ALC_C_MIN; i <= ERTS_ALC_C_MAX; i++) {
-	atom_init(&am_c[i], ERTS_ALC_C2CD(i));
-    }
-
-}
-
-static void
-init_am_a(void)
-{
-    int i;
-    am_a = (Eterm *) erts_alloc(ERTS_ALC_T_INSTR_INFO,
-				(ERTS_ALC_A_MAX+1)*sizeof(Eterm));
-
-    for (i = ERTS_ALC_A_MIN; i <= ERTS_ALC_A_MAX; i++) {
-	atom_init(&am_a[i], ERTS_ALC_A2AD(i));
-    }
-
-}
-
-static ERTS_INLINE void
-stat_upd_alloc(ErtsAlcType_t n, Uint size)
-{
-    ErtsAlcType_t t = ERTS_ALC_N2T(n);
-    ErtsAlcType_t a = ERTS_ALC_T2A(t);
-    ErtsAlcType_t c = ERTS_ALC_T2C(t);
-
-    stats->ap[a]->size += size;
-    if (stats->ap[a]->max_size < stats->ap[a]->size)
-	stats->ap[a]->max_size = stats->ap[a]->size;
-
-    stats->c[c].size += size;
-    if (stats->c[c].max_size < stats->c[c].size)
-	stats->c[c].max_size = stats->c[c].size;
-
-    stats->n[n].size += size;
-    if (stats->n[n].max_size < stats->n[n].size)
-	stats->n[n].max_size = stats->n[n].size;
-
-    stats->tot.size += size;
-    if (stats->tot.max_size < stats->tot.size)
-	stats->tot.max_size = stats->tot.size;
-
-    stats->ap[a]->blocks++;
-    if (stats->ap[a]->max_blocks < stats->ap[a]->blocks)
-	stats->ap[a]->max_blocks = stats->ap[a]->blocks;
-
-    stats->c[c].blocks++;
-    if (stats->c[c].max_blocks < stats->c[c].blocks)
-	stats->c[c].max_blocks = stats->c[c].blocks;
-
-    stats->n[n].blocks++;
-    if (stats->n[n].max_blocks < stats->n[n].blocks)
-	stats->n[n].max_blocks = stats->n[n].blocks;
-
-    stats->tot.blocks++;
-    if (stats->tot.max_blocks < stats->tot.blocks)
-	stats->tot.max_blocks = stats->tot.blocks;
-
-}
-
-
-static ERTS_INLINE void
-stat_upd_free(ErtsAlcType_t n, Uint size)
-{
-    ErtsAlcType_t t = ERTS_ALC_N2T(n);
-    ErtsAlcType_t a = ERTS_ALC_T2A(t);
-    ErtsAlcType_t c = ERTS_ALC_T2C(t);
-
-    ASSERT(stats->ap[a]->size >= size);
-    stats->ap[a]->size -= size;
-
-    ASSERT(stats->c[c].size >= size);
-    stats->c[c].size -= size;
-
-    ASSERT(stats->n[n].size >= size);
-    stats->n[n].size -= size;
-
-    ASSERT(stats->tot.size >= size);
-    stats->tot.size -= size;
-
-    ASSERT(stats->ap[a]->blocks > 0);
-    stats->ap[a]->blocks--;
-
-    ASSERT(stats->c[c].blocks > 0);
-    stats->c[c].blocks--;
-
-    ASSERT(stats->n[n].blocks > 0);
-    stats->n[n].blocks--;
-
-    ASSERT(stats->tot.blocks > 0);
-    stats->tot.blocks--;
-
-}
-
-
-static ERTS_INLINE void
-stat_upd_realloc(ErtsAlcType_t n, Uint size, Uint old_size)
-{
-    if (old_size)
-	stat_upd_free(n, old_size);
-    stat_upd_alloc(n, size);
-}
-
-/*
- * stat instrumentation callback functions
- */
-
-static void stat_pre_lock(void)
-{
-    erts_mtx_lock(&instr_mutex);
-}
-
-static void stat_pre_unlock(void)
-{
-    erts_mtx_unlock(&instr_mutex);
-}
-
-static ErtsAllocatorWrapper_t instr_wrapper;
-
-static void *
-stat_alloc(ErtsAlcType_t n, void *extra, Uint size)
-{
-    ErtsAllocatorFunctions_t *real_af = (ErtsAllocatorFunctions_t *) extra;
-    Uint ssize;
-    void *res;
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_lock(&instr_mutex);
-    }
-
-    ssize = size + STAT_BLOCK_HEADER_SIZE;
-    res = (*real_af->alloc)(n, real_af->extra, ssize);
-    if (res) {
-	stat_upd_alloc(n, size);
-	((StatBlock_t *) res)->size = size;
-#ifdef VALGRIND
-	/* Suppress "possibly leaks" by storing an actual dummy pointer
-	   to the _start_ of the allocated block.*/
-	((StatBlock_t *) res)->valgrind_leak_suppressor = res;
-#endif
-	res = (void *) ((StatBlock_t *) res)->mem;
-    }
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_unlock(&instr_mutex);
-    }
-
-    return res;
-}
-
-static void *
-stat_realloc(ErtsAlcType_t n, void *extra, void *ptr, Uint size)
-{
-    ErtsAllocatorFunctions_t *real_af = (ErtsAllocatorFunctions_t *) extra;
-    Uint old_size;
-    Uint ssize;
-    void *sptr;
-    void *res;
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_lock(&instr_mutex);
-    }
-
-    if (ptr) {
-	sptr = (void *) (((char *) ptr) - STAT_BLOCK_HEADER_SIZE);
-	old_size = ((StatBlock_t *) sptr)->size;
-    }
-    else {
-	sptr = NULL;
-	old_size = 0;
-    }
-
-    ssize = size + STAT_BLOCK_HEADER_SIZE;
-    res = (*real_af->realloc)(n, real_af->extra, sptr, ssize);
-    if (res) {
-	stat_upd_realloc(n, size, old_size);
-	((StatBlock_t *) res)->size = size;
-#ifdef VALGRIND
-	((StatBlock_t *) res)->valgrind_leak_suppressor = res;
-#endif
-	res = (void *) ((StatBlock_t *) res)->mem;
-    }
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_unlock(&instr_mutex);
-    }
-
-    return res;
-}
-
-static void
-stat_free(ErtsAlcType_t n, void *extra, void *ptr)
-{
-    ErtsAllocatorFunctions_t *real_af = (ErtsAllocatorFunctions_t *) extra;
-    void *sptr;
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_lock(&instr_mutex);
-    }
-
-    if (ptr) {
-	sptr = (void *) (((char *) ptr) - STAT_BLOCK_HEADER_SIZE);
-	stat_upd_free(n, ((StatBlock_t *) sptr)->size);
-    }
-    else {
-	sptr = NULL;
-    }
-
-    (*real_af->free)(n, real_af->extra, sptr);
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_unlock(&instr_mutex);
-    }
-
-}
-
-/*
- * map stat instrumentation callback functions
- */
-
-static void map_stat_pre_lock(void)
-{
-    erts_mtx_lock(&instr_x_mutex);
-    erts_mtx_lock(&instr_mutex);
-}
-
-static void map_stat_pre_unlock(void)
-{
-    erts_mtx_unlock(&instr_mutex);
-    erts_mtx_unlock(&instr_x_mutex);
-}
-
-static void *
-map_stat_alloc(ErtsAlcType_t n, void *extra, Uint size)
-{
-    ErtsAllocatorFunctions_t *real_af = (ErtsAllocatorFunctions_t *) extra;
-    Uint msize;
-    void *res;
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_lock(&instr_mutex);
-    }
-
-    msize = size + MAP_STAT_BLOCK_HEADER_SIZE;
-    res = (*real_af->alloc)(n, real_af->extra, msize);
-    if (res) {
-	MapStatBlock_t *mb = (MapStatBlock_t *) res;
-	stat_upd_alloc(n, size);
-
-	mb->size = size;
-	mb->type_no = n;
-	mb->pid = erts_get_current_pid();
-
-	mb->prev = NULL;
-	mb->next = mem_anchor;
-	if (mem_anchor)
-	    mem_anchor->prev = mb;
-	mem_anchor = mb;
-
-	res = (void *) mb->mem;
-    }
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_unlock(&instr_mutex);
-    }
-
-    return res;
-}
-
-static void *
-map_stat_realloc(ErtsAlcType_t n, void *extra, void *ptr, Uint size)
-{
-    ErtsAllocatorFunctions_t *real_af = (ErtsAllocatorFunctions_t *) extra;
-    Uint old_size;
-    Uint msize;
-    void *mptr;
-    void *res;
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_lock(&instr_x_mutex);
-	erts_mtx_lock(&instr_mutex);
-    }
-
-    if (ptr) {
-	mptr = (void *) (((char *) ptr) - MAP_STAT_BLOCK_HEADER_SIZE);
-	old_size = ((MapStatBlock_t *) mptr)->size;
-    }
-    else {
-	mptr = NULL;
-	old_size = 0;
-    }
-
-    msize = size + MAP_STAT_BLOCK_HEADER_SIZE;
-    res = (*real_af->realloc)(n, real_af->extra, mptr, msize);
-    if (res) {
-	MapStatBlock_t *mb = (MapStatBlock_t *) res;
-
-	mb->size = size;
-	mb->type_no = n;
-	mb->pid = erts_get_current_pid();
-
-	stat_upd_realloc(n, size, old_size);
-
-	if (mptr != res) {
-
-	    if (mptr) {
-		if (mb->prev)
-		    mb->prev->next = mb;
-		else {
-		    ASSERT(mem_anchor == (MapStatBlock_t *) mptr);
-		    mem_anchor = mb;
-		}
-		if (mb->next)
-		    mb->next->prev = mb;
-	    }
-	    else {
-		mb->prev = NULL;
-		mb->next = mem_anchor;
-		if (mem_anchor)
-		    mem_anchor->prev = mb;
-		mem_anchor = mb;
-	    }
-
-	}
-
-	res = (void *) mb->mem;
-    }
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_unlock(&instr_mutex);
-	erts_mtx_unlock(&instr_x_mutex);
-    }
-
-    return res;
-}
-
-static void
-map_stat_free(ErtsAlcType_t n, void *extra, void *ptr)
-{
-    ErtsAllocatorFunctions_t *real_af = (ErtsAllocatorFunctions_t *) extra;
-    void *mptr;
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_lock(&instr_x_mutex);
-	erts_mtx_lock(&instr_mutex);
-    }
-
-    if (ptr) {
-	MapStatBlock_t *mb;
-
-	mptr = (void *) (((char *) ptr) - MAP_STAT_BLOCK_HEADER_SIZE);
-	mb = (MapStatBlock_t *) mptr;
-
-	stat_upd_free(n, mb->size);
-
-	if (mb->prev)
-	    mb->prev->next = mb->next;
-	else
-	    mem_anchor = mb->next;
-	if (mb->next)
-	    mb->next->prev = mb->prev;
-    }
-    else {
-	mptr = NULL;
-    }
-
-    (*real_af->free)(n, real_af->extra, mptr);
-
-    if (!erts_is_allctr_wrapper_prelocked()) {
-	erts_mtx_unlock(&instr_mutex);
-	erts_mtx_unlock(&instr_x_mutex);
-    }
-
-}
-
-static void dump_memory_map_to_stream(fmtfn_t to, void* to_arg)
-{
-    ErtsAlcType_t n;
-    MapStatBlock_t *bp;
-    int lock = !ERTS_IS_CRASH_DUMPING;
-    if (lock) {
-	ASSERT(!erts_is_allctr_wrapper_prelocked());
-	erts_mtx_lock(&instr_mutex);
-    }
-
-    /* Write header */
-
-    erts_cbprintf(to, to_arg,
-	    "{instr_hdr,\n"
-	    " %lu,\n"
-	    " %lu,\n"
-	    " {",
-	    (unsigned long) ERTS_INSTR_VSN,
-	    (unsigned long) MAP_STAT_BLOCK_HEADER_SIZE);
-
-#if ERTS_ALC_N_MIN != 1
-#error ERTS_ALC_N_MIN is not 1
-#endif
-
-    for (n = ERTS_ALC_N_MIN; n <= ERTS_ALC_N_MAX; n++) {
-	ErtsAlcType_t t = ERTS_ALC_N2T(n);
-	ErtsAlcType_t a = ERTS_ALC_T2A(t);
-	ErtsAlcType_t c = ERTS_ALC_T2C(t);
-	const char *astr;
-
-	if (erts_allctrs_info[a].enabled)
-	    astr = ERTS_ALC_A2AD(a);
-	else
-	    astr = ERTS_ALC_A2AD(ERTS_ALC_A_SYSTEM);
-
-	erts_cbprintf(to, to_arg,
-		"%s{%s,%s,%s}%s",
-		(n == ERTS_ALC_N_MIN) ? "" : "  ",
-		ERTS_ALC_N2TD(n),
-		astr,
-		ERTS_ALC_C2CD(c),
-		(n == ERTS_ALC_N_MAX) ? "" : ",\n");
-    }
-
-    erts_cbprintf(to, to_arg, "}}.\n");
-
-    /* Write memory data */
-    for (bp = mem_anchor; bp; bp = bp->next) {
-	if (is_internal_pid(bp->pid))
-	    erts_cbprintf(to, to_arg,
-		    "{%lu, %lu, %lu, {%lu,%lu,%lu}}.\n",
-		    (UWord) bp->type_no,
-		    (UWord) bp->mem,
-		    (UWord) bp->size,
-		    (UWord) pid_channel_no(bp->pid),
-		    (UWord) pid_number(bp->pid),
-		    (UWord) pid_serial(bp->pid));
-	else
-	    erts_cbprintf(to, to_arg,
-		    "{%lu, %lu, %lu, undefined}.\n",
-		    (UWord) bp->type_no,
-		    (UWord) bp->mem,
-		    (UWord) bp->size);
-    }
-
-    if (lock)
-	erts_mtx_unlock(&instr_mutex);
-}
-
-int erts_instr_dump_memory_map_to(fmtfn_t to, void* to_arg)
-{
-    if (!erts_instr_memory_map)
-	return 0;
-
-    dump_memory_map_to_stream(to, to_arg);
-    return 1;
-}
-
-int erts_instr_dump_memory_map(const char *name)
-{
-    int fd;
-
-    if (!erts_instr_memory_map)
-	return 0;
-
-    fd = open(name, O_WRONLY | O_CREAT | O_TRUNC, 0640);
-    if (fd < 0)
-	return 0;
-
-    dump_memory_map_to_stream(erts_write_fd, (void*)&fd);
-
-    close(fd);
-    return 1;
-}
-
-Eterm erts_instr_get_memory_map(Process *proc)
-{
-    MapStatBlock_t *org_mem_anchor;
-    Eterm hdr_tuple, md_list, res;
-    Eterm *hp;
-    Uint hsz;
-    MapStatBlock_t *bp;
-#ifdef DEBUG
-    Eterm *end_hp;
-#endif
-    
-    if (!erts_instr_memory_map)
-	return am_false;
-
-    if (!atoms_initialized)
-	init_atoms();
-    if (!am_n)
-	init_am_n();
-    if (!am_c)
-	init_am_c();
-    if (!am_a)
-	init_am_a();
-
-    erts_mtx_lock(&instr_x_mutex);
-    erts_mtx_lock(&instr_mutex);
-
-    /* Header size */
-    hsz = 5 + 1 + (ERTS_ALC_N_MAX+1-ERTS_ALC_N_MIN)*(1 + 4);
-
-    /* Memory data list */
-    for (bp = mem_anchor; bp; bp = bp->next) {
-	if (is_internal_pid(bp->pid)) {
-#if (_PID_NUM_SIZE - 1 > MAX_SMALL)
-	    if (internal_pid_number(bp->pid) > MAX_SMALL)
-		hsz += BIG_UINT_HEAP_SIZE;
-#endif
-#if (_PID_SER_SIZE - 1 > MAX_SMALL)
-	    if (internal_pid_serial(bp->pid) > MAX_SMALL)
-		hsz += BIG_UINT_HEAP_SIZE;
-#endif
-	    hsz += 4;
-	}
-
-	if ((UWord) bp->mem > MAX_SMALL)
-	    hsz += BIG_UINT_HEAP_SIZE;
-	if (bp->size > MAX_SMALL)
-	    hsz += BIG_UINT_HEAP_SIZE;
-
-	hsz += 5 + 2;
-    }
-
-    hsz += 3; /* Root tuple */
-
-    org_mem_anchor = mem_anchor;
-    mem_anchor = NULL;
-
-    erts_mtx_unlock(&instr_mutex);
-
-    hp = HAlloc(proc, hsz); /* May end up calling map_stat_alloc() */
-
-    erts_mtx_lock(&instr_mutex);
-
-#ifdef DEBUG
-    end_hp = hp + hsz;
-#endif
-
-    {	/* Build header */
-	ErtsAlcType_t n;
-	Eterm type_map;
-	Uint *hp2 = hp;
-#ifdef DEBUG
-	Uint *hp2_end;
-#endif
-
-	hp += (ERTS_ALC_N_MAX + 1 - ERTS_ALC_N_MIN)*4;
-
-#ifdef DEBUG
-	hp2_end = hp;
-#endif
-
-	type_map = make_tuple(hp);
-	*(hp++) = make_arityval(ERTS_ALC_N_MAX + 1 - ERTS_ALC_N_MIN);
-
-	for (n = ERTS_ALC_N_MIN; n <= ERTS_ALC_N_MAX; n++) {
-	    ErtsAlcType_t t = ERTS_ALC_N2T(n);
-	    ErtsAlcType_t a = ERTS_ALC_T2A(t);
-	    ErtsAlcType_t c = ERTS_ALC_T2C(t);
-
-	    if (!erts_allctrs_info[a].enabled)
-		a = ERTS_ALC_A_SYSTEM;
-
-	    *(hp++) = TUPLE3(hp2, am_n[n], am_a[a], am_c[c]);
-	    hp2 += 4;
-	}
-
-	ASSERT(hp2 == hp2_end);
-
-	hdr_tuple = TUPLE4(hp,
-			   am.instr_hdr,
-			   make_small(ERTS_INSTR_VSN),
-			   make_small(MAP_STAT_BLOCK_HEADER_SIZE),
-			   type_map);
-
-	hp += 5;
-    }
-
-    /* Build memory data list */
-
-    for (md_list = NIL, bp = org_mem_anchor; bp; bp = bp->next) {
-	Eterm tuple;
-	Eterm type;
-	Eterm ptr;
-	Eterm size;
-	Eterm pid;
-
-	if (is_not_internal_pid(bp->pid))
-	    pid = am_undefined;
-	else {
-	    Eterm c;
-	    Eterm n;
-	    Eterm s;
-
-#if (ERST_INTERNAL_CHANNEL_NO > MAX_SMALL)
-#error Oversized internal channel number
-#endif
-	    c = make_small(ERST_INTERNAL_CHANNEL_NO);
-
-#if (_PID_NUM_SIZE - 1 > MAX_SMALL)
-	    if (internal_pid_number(bp->pid) > MAX_SMALL) {
-		n = uint_to_big(internal_pid_number(bp->pid), hp);
-		hp += BIG_UINT_HEAP_SIZE;
-	    }
-	    else
-#endif
-		n = make_small(internal_pid_number(bp->pid));
-
-#if (_PID_SER_SIZE - 1 > MAX_SMALL)
-	    if (internal_pid_serial(bp->pid) > MAX_SMALL) {
-		s = uint_to_big(internal_pid_serial(bp->pid), hp);
-		hp += BIG_UINT_HEAP_SIZE;
-	    }
-	    else
-#endif
-		s = make_small(internal_pid_serial(bp->pid));
-	    pid = TUPLE3(hp, c, n, s);
-	    hp += 4;
-	}
-
-
-#if ERTS_ALC_N_MAX > MAX_SMALL
-#error Oversized memory type number
-#endif
-	type = make_small(bp->type_no);
-
-	if ((UWord) bp->mem > MAX_SMALL) {
-	    ptr = uint_to_big((UWord) bp->mem, hp);
-	    hp += BIG_UINT_HEAP_SIZE;
-	}
-	else
-	    ptr = make_small((UWord) bp->mem);
-
-	if (bp->size > MAX_SMALL) {
-	    size = uint_to_big(bp->size, hp);
-	    hp += BIG_UINT_HEAP_SIZE;
-	}
-	else
-	    size = make_small(bp->size);
-
-	tuple = TUPLE4(hp, type, ptr, size, pid);
-	hp += 5;
-
-	md_list = CONS(hp, tuple, md_list);
-	hp += 2;
-    }
-
-    res = TUPLE2(hp, hdr_tuple, md_list);
-    
-    ASSERT(hp + 3 == end_hp);
-
-    if (mem_anchor) {
-	for (bp = mem_anchor; bp->next; bp = bp->next)
-	    ;
-	ASSERT(org_mem_anchor);
-	org_mem_anchor->prev = bp; 
-	bp->next = org_mem_anchor;
-    }
-    else {
-	mem_anchor = org_mem_anchor;
-    }
-
-    erts_mtx_unlock(&instr_mutex);
-    erts_mtx_unlock(&instr_x_mutex);
-
-    return res;
-}
-
-static ERTS_INLINE void
-begin_new_max_period(Stat_t *stat, int min, int max)
-{
-    int i;
-    for (i = min; i <= max; i++) {
-	stat[i].max_size = stat[i].size;
-	stat[i].max_blocks = stat[i].blocks;
-    }
-}
-
-static ERTS_INLINE void
-update_max_ever_values(Stat_t *stat, int min, int max)
-{
-    int i;
-    for (i = min; i <= max; i++) {
-	if (stat[i].max_size_ever < stat[i].max_size)
-	    stat[i].max_size_ever = stat[i].max_size;
-	if (stat[i].max_blocks_ever < stat[i].max_blocks)
-	    stat[i].max_blocks_ever = stat[i].max_blocks;
-    }
-}
-
-#define bld_string	erts_bld_string
-#define bld_tuple	erts_bld_tuple
-#define bld_tuplev	erts_bld_tuplev
-#define bld_list	erts_bld_list
-#define bld_2tup_list	erts_bld_2tup_list
-#define bld_uint	erts_bld_uint
-
-Eterm
-erts_instr_get_stat(Process *proc, Eterm what, int begin_max_period)
-{
-    int i, len, max, min, allctr;
-    Eterm *names, *values, res;
-    Uint arr_size, stat_size, hsz, *hszp, *hp, **hpp;
-    Stat_t *stat_src, *stat;
-
-    if (!erts_instr_stat)
-	return am_false;
-
-    if (!atoms_initialized)
-	init_atoms();
-
-    if (what == am.total) {
-	min		= 0;
-	max		= 0;
-	allctr		= 0;
-	stat_size	= sizeof(Stat_t);
-	stat_src	= &stats->tot;
-	if (!am_tot)
-	    init_am_tot();
-	names		= am_tot;
-    }
-    else if (what == am.allocators) {
-	min		= ERTS_ALC_A_MIN;
-	max		= ERTS_ALC_A_MAX;
-	allctr		= 1;
-	stat_size	= sizeof(Stat_t)*(ERTS_ALC_A_MAX+1);
-	stat_src	= stats->a;
-	if (!am_a)
-	    init_am_a();
-	names		= am_a;
-    }
-    else if (what == am.classes) {
-	min		= ERTS_ALC_C_MIN;
-	max		= ERTS_ALC_C_MAX;
-	allctr		= 0;
-	stat_size	= sizeof(Stat_t)*(ERTS_ALC_C_MAX+1);
-	stat_src	= stats->c;
-	if (!am_c)
-	    init_am_c();
-	names		= &am_c[ERTS_ALC_C_MIN];
-    }
-    else if (what == am.types) {
-	min		= ERTS_ALC_N_MIN;
-	max		= ERTS_ALC_N_MAX;
-	allctr		= 0;
-	stat_size	= sizeof(Stat_t)*(ERTS_ALC_N_MAX+1);
-	stat_src	= stats->n;
-	if (!am_n)
-	    init_am_n();
-	names		= &am_n[ERTS_ALC_N_MIN];
-    }
-    else {
-	return THE_NON_VALUE;
-    }
-
-    stat = (Stat_t *) erts_alloc(ERTS_ALC_T_TMP, stat_size);
-
-    arr_size = (max - min + 1)*sizeof(Eterm);
-
-    if (allctr)
-	names = (Eterm *) erts_alloc(ERTS_ALC_T_TMP, arr_size);
-
-    values = (Eterm *) erts_alloc(ERTS_ALC_T_TMP, arr_size);
-
-    erts_mtx_lock(&instr_mutex);
-
-    update_max_ever_values(stat_src, min, max);
-
-    sys_memcpy((void *) stat, (void *) stat_src, stat_size);
-
-    if (begin_max_period)
-	begin_new_max_period(stat_src, min, max);
-
-    erts_mtx_unlock(&instr_mutex);
-
-    hsz = 0;
-    hszp = &hsz;
-    hpp = NULL;
-
- restart_bld:
-
-    len = 0;
-    for (i = min; i <= max; i++) {
-	if (!allctr || erts_allctrs_info[i].enabled) {
-	    Eterm s[2];
-
-	    if (allctr)
-		names[len] = am_a[i];
-	    
-	    s[0] = bld_tuple(hpp, hszp, 4,
-			     am.sizes,
-			     bld_uint(hpp, hszp, stat[i].size),
-			     bld_uint(hpp, hszp, stat[i].max_size),
-			     bld_uint(hpp, hszp, stat[i].max_size_ever));
-
-	    s[1] = bld_tuple(hpp, hszp, 4,
-			     am.blocks,
-			     bld_uint(hpp, hszp, stat[i].blocks),
-			     bld_uint(hpp, hszp, stat[i].max_blocks),
-			     bld_uint(hpp, hszp, stat[i].max_blocks_ever));
-
-	    values[len] = bld_list(hpp, hszp, 2, s);
-	    
-	    len++;
-	}
-    }
-
-    res = bld_2tup_list(hpp, hszp, len, names, values);
-
-    if (!hpp) {
-	hp = HAlloc(proc, hsz);
-	hszp = NULL;
-	hpp = &hp;
-	goto restart_bld;
-    }
-
-    erts_free(ERTS_ALC_T_TMP, (void *) stat);
-    erts_free(ERTS_ALC_T_TMP, (void *) values);
-    if (allctr)
-	erts_free(ERTS_ALC_T_TMP, (void *) names);
-
-    return res;
-}
-
-static void
-dump_stat_to_stream(fmtfn_t to, void* to_arg, int begin_max_period)
-{
-    ErtsAlcType_t i, a_max, a_min;
-
-    erts_mtx_lock(&instr_mutex);
-
-    erts_cbprintf(to, to_arg,
-	    "{instr_vsn,%lu}.\n",
-	    (unsigned long) ERTS_INSTR_VSN);
-    
-    update_max_ever_values(&stats->tot, 0, 0);
-
-    erts_cbprintf(to, to_arg,
-	    "{total,[{total,[{sizes,%lu,%lu,%lu},{blocks,%lu,%lu,%lu}]}]}.\n",
-	    (UWord) stats->tot.size,
-	    (UWord) stats->tot.max_size,
-	    (UWord) stats->tot.max_size_ever,
-	    (UWord) stats->tot.blocks,
-	    (UWord) stats->tot.max_blocks,
-	    (UWord) stats->tot.max_blocks_ever);
-
-    a_max = 0;
-    a_min = ~0;
-    for (i = ERTS_ALC_A_MIN; i <= ERTS_ALC_A_MAX; i++) {
-	if (erts_allctrs_info[i].enabled) {
-	    if (a_min > i)
-		a_min = i;
-	    if (a_max < i)
-		a_max = i;
-	}
-    }
-
-    ASSERT(ERTS_ALC_A_MIN <= a_min && a_min <= ERTS_ALC_A_MAX);
-    ASSERT(ERTS_ALC_A_MIN <= a_max && a_max <= ERTS_ALC_A_MAX);
-    ASSERT(a_min <= a_max);
-
-    update_max_ever_values(stats->a, a_min, a_max);
-
-    for (i = ERTS_ALC_A_MIN; i <= ERTS_ALC_A_MAX; i++) {
-	if (erts_allctrs_info[i].enabled) {
-	    erts_cbprintf(to, to_arg,
-		    "%s{%s,[{sizes,%lu,%lu,%lu},{blocks,%lu,%lu,%lu}]}%s",
-		    i == a_min ? "{allocators,\n [" : "  ",
-		    ERTS_ALC_A2AD(i),
-		    (UWord) stats->a[i].size,
-		    (UWord) stats->a[i].max_size,
-		    (UWord) stats->a[i].max_size_ever,
-		    (UWord) stats->a[i].blocks,
-		    (UWord) stats->a[i].max_blocks,
-		    (UWord) stats->a[i].max_blocks_ever,
-		    i == a_max ? "]}.\n" : ",\n");
-	}
-    }
-
-    update_max_ever_values(stats->c, ERTS_ALC_C_MIN, ERTS_ALC_C_MAX);
-
-    for (i = ERTS_ALC_C_MIN; i <= ERTS_ALC_C_MAX; i++) {
-	erts_cbprintf(to, to_arg,
-		"%s{%s,[{sizes,%lu,%lu,%lu},{blocks,%lu,%lu,%lu}]}%s",
-		i == ERTS_ALC_C_MIN ? "{classes,\n [" : "  ",
-		ERTS_ALC_C2CD(i),
-		(UWord) stats->c[i].size,
-		(UWord) stats->c[i].max_size,
-		(UWord) stats->c[i].max_size_ever,
-		(UWord) stats->c[i].blocks,
-		(UWord) stats->c[i].max_blocks,
-		(UWord) stats->c[i].max_blocks_ever,
-		i == ERTS_ALC_C_MAX ? "]}.\n" :  ",\n" );
-    }
-
-    update_max_ever_values(stats->n, ERTS_ALC_N_MIN, ERTS_ALC_N_MAX);
-
-    for (i = ERTS_ALC_N_MIN; i <= ERTS_ALC_N_MAX; i++) {
-	erts_cbprintf(to, to_arg,
-		"%s{%s,[{sizes,%lu,%lu,%lu},{blocks,%lu,%lu,%lu}]}%s",
-		i == ERTS_ALC_N_MIN ? "{types,\n [" : "  ",
-		ERTS_ALC_N2TD(i),
-		(UWord) stats->n[i].size,
-		(UWord) stats->n[i].max_size,
-		(UWord) stats->n[i].max_size_ever,
-		(UWord) stats->n[i].blocks,
-		(UWord) stats->n[i].max_blocks,
-		(UWord) stats->n[i].max_blocks_ever,
-		i == ERTS_ALC_N_MAX ? "]}.\n" :  ",\n" );
-    }
-
-    if (begin_max_period) {
-	begin_new_max_period(&stats->tot, 0, 0);
-	begin_new_max_period(stats->a, a_min, a_max);
-	begin_new_max_period(stats->c, ERTS_ALC_C_MIN, ERTS_ALC_C_MAX);
-	begin_new_max_period(stats->n, ERTS_ALC_N_MIN, ERTS_ALC_N_MAX);
-    }
-
-    erts_mtx_unlock(&instr_mutex);
-
-}
-
-int erts_instr_dump_stat_to(fmtfn_t to, void* to_arg, int begin_max_period)
-{
-    if (!erts_instr_stat)
-	return 0;
-
-    dump_stat_to_stream(to, to_arg, begin_max_period);
-    return 1;
-}
-
-int erts_instr_dump_stat(const char *name, int begin_max_period)
-{
-    int fd;
-
-    if (!erts_instr_stat)
-	return 0;
-
-    fd = open(name, O_WRONLY | O_CREAT | O_TRUNC,0640);
-    if (fd < 0)
-	return 0;
-
-    dump_stat_to_stream(erts_write_fd, (void*)&fd, begin_max_period);
-
-    close(fd);
-    return 1;
-}
-
-
-Uint
-erts_instr_get_total(void)
-{
-    return erts_instr_stat ? stats->tot.size : 0;
-}
-
-Uint
-erts_instr_get_max_total(void)
-{
-    if (erts_instr_stat) {
-	update_max_ever_values(&stats->tot, 0, 0);
-	return stats->tot.max_size_ever;
-    }
-    return 0;
-}
-
-Eterm
-erts_instr_get_type_info(Process *proc)
-{
-    Eterm res, *tpls;
-    Uint hsz, *hszp, *hp, **hpp;
-    ErtsAlcType_t n;
-
-    if (!am_n)
-	init_am_n();
-    if (!am_a)
-	init_am_a();
-    if (!am_c)
-	init_am_c();
-
-    tpls = (Eterm *) erts_alloc(ERTS_ALC_T_TMP,
-				(ERTS_ALC_N_MAX-ERTS_ALC_N_MIN+1)
-				* sizeof(Eterm));
-    hsz = 0;
-    hszp = &hsz;
-    hpp = NULL;
-
- restart_bld:
-
-#if ERTS_ALC_N_MIN != 1
-#error ERTS_ALC_N_MIN is not 1
-#endif
-
-    for (n = ERTS_ALC_N_MIN; n <= ERTS_ALC_N_MAX; n++) {
-	ErtsAlcType_t t = ERTS_ALC_N2T(n);
-	ErtsAlcType_t a = ERTS_ALC_T2A(t);
-	ErtsAlcType_t c = ERTS_ALC_T2C(t);
-
-	if (!erts_allctrs_info[a].enabled)
-	    a = ERTS_ALC_A_SYSTEM;
-
-	tpls[n - ERTS_ALC_N_MIN]
-	    = bld_tuple(hpp, hszp, 3, am_n[n], am_a[a], am_c[c]);
-    }
-
-    res = bld_tuplev(hpp, hszp, ERTS_ALC_N_MAX-ERTS_ALC_N_MIN+1, tpls);
-    
-    if (!hpp) {
-	hp = HAlloc(proc, hsz);
-	hszp = NULL;
-	hpp = &hp;
-	goto restart_bld;
-    }
-
-    erts_free(ERTS_ALC_T_TMP, tpls);
-
-    return res;
-}
-
-Uint
-erts_instr_init(int stat, int map_stat)
-{
-    Uint extra_sz;
-    int i;
-
-    am_tot = NULL;
-    am_n = NULL;
-    am_c = NULL;
-    am_a = NULL;
-
-    erts_instr_memory_map = 0;
-    erts_instr_stat = 0;
-    atoms_initialized = 0;
-
-    if (!stat && !map_stat)
-	return 0;
-
-    stats = erts_alloc(ERTS_ALC_T_INSTR_INFO, sizeof(struct stats_));
-
-    erts_mtx_init(&instr_mutex, "instr", NIL,
-        ERTS_LOCK_FLAGS_PROPERTY_STATIC | ERTS_LOCK_FLAGS_CATEGORY_DEBUG);
-
-    mem_anchor = NULL;
-
-    /* Install instrumentation functions */
-    ERTS_CT_ASSERT(sizeof(erts_allctrs) == sizeof(real_allctrs));
-
-    sys_memcpy((void *)real_allctrs,(void *)erts_allctrs,sizeof(erts_allctrs));
-
-    sys_memzero((void *) &stats->tot, sizeof(Stat_t));
-    sys_memzero((void *) stats->a, sizeof(Stat_t)*(ERTS_ALC_A_MAX+1));
-    sys_memzero((void *) stats->c, sizeof(Stat_t)*(ERTS_ALC_C_MAX+1));
-    sys_memzero((void *) stats->n, sizeof(Stat_t)*(ERTS_ALC_N_MAX+1));
-
-    for (i = ERTS_ALC_A_MIN; i <= ERTS_ALC_A_MAX; i++) {
-	if (erts_allctrs_info[i].enabled)
-	    stats->ap[i] = &stats->a[i];
-	else
-	    stats->ap[i] = &stats->a[ERTS_ALC_A_SYSTEM];
-    }
-
-    if (map_stat) {
-
-	erts_mtx_init(&instr_x_mutex, "instr_x", NIL,
-        ERTS_LOCK_FLAGS_PROPERTY_STATIC | ERTS_LOCK_FLAGS_CATEGORY_DEBUG);
-
-	erts_instr_memory_map = 1;
-	erts_instr_stat = 1;
-	for (i = ERTS_ALC_A_MIN; i <= ERTS_ALC_A_MAX; i++) {
-	    erts_allctrs[i].alloc	= map_stat_alloc;
-	    erts_allctrs[i].realloc	= map_stat_realloc;
-	    erts_allctrs[i].free	= map_stat_free;
-	    erts_allctrs[i].extra	= (void *) &real_allctrs[i];
-	}
-	instr_wrapper.lock = map_stat_pre_lock;
-	instr_wrapper.unlock = map_stat_pre_unlock;
-	extra_sz = MAP_STAT_BLOCK_HEADER_SIZE;
-    }
-    else {
-	erts_instr_stat = 1;
-	for (i = ERTS_ALC_A_MIN; i <= ERTS_ALC_A_MAX; i++) {
-	    erts_allctrs[i].alloc	= stat_alloc;
-	    erts_allctrs[i].realloc	= stat_realloc;
-	    erts_allctrs[i].free	= stat_free;
-	    erts_allctrs[i].extra	= (void *) &real_allctrs[i];
-	}
-	instr_wrapper.lock = stat_pre_lock;
-	instr_wrapper.unlock = stat_pre_unlock;
-	extra_sz = STAT_BLOCK_HEADER_SIZE;
-    }
-    erts_allctr_wrapper_prelock_init(&instr_wrapper);
-    return extra_sz;
-}
-
diff --git a/erts/emulator/beam/erl_instrument.h b/erts/emulator/beam/erl_instrument.h
deleted file mode 100644
index 351172b2fa..0000000000
--- a/erts/emulator/beam/erl_instrument.h
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * %CopyrightBegin%
- * 
- * Copyright Ericsson AB 2003-2016. All Rights Reserved.
- * 
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * 
- * %CopyrightEnd%
- */
-
-#ifndef ERL_INSTRUMENT_H__
-#define ERL_INSTRUMENT_H__
-
-#include "erl_mtrace.h"
-
-#define ERTS_INSTR_VSN 2
-
-extern int erts_instr_memory_map;
-extern int erts_instr_stat;
-
-Uint  erts_instr_init(int stat, int map_stat);
-int   erts_instr_dump_memory_map_to(fmtfn_t to, void* to_arg);
-int   erts_instr_dump_memory_map(const char *name);
-Eterm erts_instr_get_memory_map(Process *process);
-int   erts_instr_dump_stat_to(fmtfn_t to, void* to_arg, int begin_max_period);
-int   erts_instr_dump_stat(const char *name, int begin_max_period);
-Eterm erts_instr_get_stat(Process *proc, Eterm what, int begin_max_period);
-Eterm erts_instr_get_type_info(Process *proc);
-Uint  erts_instr_get_total(void);
-Uint  erts_instr_get_max_total(void);
-
-#endif
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 0e0013e8a4..260656e2d3 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -388,12 +388,18 @@ erts_call_dirty_nif(ErtsSchedulerData *esdp, Process *c_p, BeamInstr *I, Eterm *
     erts_atomic32_read_band_mb(&c_p->state, ~(ERTS_PSFLG_DIRTY_CPU_PROC
 						   | ERTS_PSFLG_DIRTY_IO_PROC));
 
+    ASSERT(esdp->current_nif == NULL);
+    esdp->current_nif = &env;
+
     erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
 
     result = (*dirty_nif)(&env, codemfa->arity, argv); /* Call dirty NIF */
 
     erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
 
+    ASSERT(esdp->current_nif == &env);
+    esdp->current_nif = NULL;
+
     ASSERT(env.proc->static_flags & ERTS_STC_FLG_SHADOW_PROC);
     ASSERT(env.proc->next == c_p);
 
@@ -4258,6 +4264,10 @@ int erts_nif_get_funcs(struct erl_module_nif* mod,
     return mod->entry.num_of_funcs;
 }
 
+Module *erts_nif_get_module(struct erl_module_nif *nif_mod) {
+    return nif_mod->mod;
+}
+
 Eterm erts_nif_call_function(Process *p, Process *tracee,
                              struct erl_module_nif* mod,
                              ErlNifFunc *fun, int argc, Eterm *argv)
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index e8f58a196a..650ec0958c 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -36,7 +36,6 @@
 #include "erl_db.h"
 #include "dist.h"
 #include "beam_catches.h"
-#include "erl_instrument.h"
 #include "erl_threads.h"
 #include "erl_binary.h"
 #include "beam_bp.h"
@@ -2508,6 +2507,8 @@ handle_yield(ErtsAuxWorkData *awdp, erts_aint32_t aux_work, int waiting)
 
     yield |= erts_handle_yielded_ets_all_request(awdp->esdp,
                                                  &awdp->yield.ets_all);
+    yield |= erts_handle_yielded_alcu_blockscan(awdp->esdp,
+                                                &awdp->yield.alcu_blockscan);
 
     /*
      * Other yielding operations...
@@ -5698,6 +5699,7 @@ init_scheduler_data(ErtsSchedulerData* esdp, int num,
     esdp->ssi = ssi;
     esdp->current_process = NULL;
     esdp->current_port = NULL;
+    esdp->current_nif = NULL;
 
     esdp->virtual_reds = 0;
     esdp->cpu_id = -1;
@@ -8333,6 +8335,7 @@ sched_thread_func(void *vesdp)
     ERTS_VERIFY_UNUSED_TEMP_ALLOC(NULL);
 #endif
 
+    erts_alcu_sched_spec_data_init(esdp);
     erts_ets_sched_spec_data_init(esdp);
 
     process_main(esdp->x_reg_array, esdp->f_reg_array);
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index e232776016..e2aa1d9f84 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -593,6 +593,7 @@ typedef struct {
 	ErtsDelayedAuxWorkWakeupJob *job;
     } delayed_wakeup;
     struct {
+        ErtsAlcuBlockscanYieldData alcu_blockscan;
         ErtsEtsAllYieldData ets_all;
         /* Other yielding operations... */
     } yield;
@@ -637,6 +638,7 @@ struct ErtsSchedulerData_ {
     ErtsSchedType type;
     Uint no;			/* Scheduler number for normal schedulers */
     Uint dirty_no;  /* Scheduler number for dirty schedulers */
+    struct enif_environment_t *current_nif;
     Process *dirty_shadow_process;
     Port *current_port;
     ErtsRunQueue *run_queue;
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 256670ff22..2cf268162d 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -123,6 +123,7 @@ void erts_unload_nif(struct erl_module_nif* nif);
 extern void erl_nif_init(void);
 extern int erts_nif_get_funcs(struct erl_module_nif*,
                               struct enif_func_t **funcs);
+extern Module *erts_nif_get_module(struct erl_module_nif*);
 extern Eterm erts_nif_call_function(Process *p, Process *tracee,
                                     struct erl_module_nif*,
                                     struct enif_func_t *,
@@ -200,6 +201,7 @@ typedef struct {
 struct erts_driver_t_ {
     erts_driver_t *next;
     erts_driver_t *prev;
+    Eterm name_atom;
     char *name;
     struct {
 	int major;
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index 66b8005975..2446b3c074 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -956,6 +956,9 @@ try_imm_drv_call(ErtsTryImmDrvCallState *sp)
 
 	reds_left_in = ERTS_BIF_REDS_LEFT(c_p);
 	erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
+
+        ASSERT((c_p->scheduler_data)->current_port == NULL);
+        (c_p->scheduler_data)->current_port = prt;
     }
 
     ASSERT(0 <= reds_left_in && reds_left_in <= CONTEXT_REDS);
@@ -1017,6 +1020,9 @@ finalize_imm_drv_call(ErtsTryImmDrvCallState *sp)
     erts_port_release(prt);
 
     if (c_p) {
+        ASSERT((c_p->scheduler_data)->current_port == prt);
+        (c_p->scheduler_data)->current_port = NULL;
+
 	erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
 
 	if (reds != (CONTEXT_REDS - sp->reds_left_in)) {
@@ -2906,11 +2912,8 @@ static void lcnt_enable_driver_lock_count(erts_driver_t *dp, int enable)
 {
     if (dp->lock) {
         if (enable) {
-            Eterm name_as_atom = erts_atom_put((byte*)dp->name, sys_strlen(dp->name),
-                                                ERTS_ATOM_ENC_LATIN1, 1);
-
-            erts_lcnt_install_new_lock_info(&dp->lock->lcnt, "driver_lock", name_as_atom,
-                ERTS_LOCK_TYPE_MUTEX | ERTS_LOCK_FLAGS_CATEGORY_IO);
+            erts_lcnt_install_new_lock_info(&dp->lock->lcnt, "driver_lock",
+                dp->name_atom, ERTS_LOCK_TYPE_MUTEX | ERTS_LOCK_FLAGS_CATEGORY_IO);
         } else {
             erts_lcnt_uninstall(&dp->lock->lcnt);
         }
@@ -7357,7 +7360,11 @@ no_stop_select_callback(ErlDrvEvent event, void* private)
 static int
 init_driver(erts_driver_t *drv, ErlDrvEntry *de, DE_Handle *handle)
 {
+    drv->name_atom = erts_atom_put((byte*)de->driver_name,
+                                   sys_strlen(de->driver_name),
+                                   ERTS_ATOM_ENC_LATIN1, 1);
     drv->name = de->driver_name;
+
     ASSERT(de->extended_marker == ERL_DRV_EXTENDED_MARKER);
     ASSERT(de->major_version >= 2);
     drv->version.major = de->major_version;
@@ -7367,13 +7374,10 @@ init_driver(erts_driver_t *drv, ErlDrvEntry *de, DE_Handle *handle)
     if (drv->flags & ERL_DRV_FLAG_USE_PORT_LOCKING) {
         drv->lock = NULL;
     } else {
-        Eterm driver_id = erts_atom_put((byte *) drv->name,
-                                        sys_strlen(drv->name),
-                                        ERTS_ATOM_ENC_LATIN1, 1);
-
         drv->lock = erts_alloc(ERTS_ALC_T_DRIVER_LOCK, sizeof(erts_mtx_t));
 
-        erts_mtx_init(drv->lock, "driver_lock", driver_id, ERTS_LOCK_FLAGS_CATEGORY_IO);
+        erts_mtx_init(drv->lock, "driver_lock", drv->name_atom,
+                      ERTS_LOCK_FLAGS_CATEGORY_IO);
     }
     drv->entry = de;
 
@@ -7459,18 +7463,12 @@ int erts_add_driver_entry(ErlDrvEntry *de, DE_Handle *handle,
 	erts_tsd_set(driver_list_lock_status_key, (void *) 1);
     }
 
-    if (taint) {
-        Eterm name_atom = erts_atom_put((byte*)de->driver_name,
-                                        sys_strlen(de->driver_name),
-                                        ERTS_ATOM_ENC_LATIN1, 0);
-        if (is_atom(name_atom))
-            erts_add_taint(name_atom);
-        else
-            err = 1;
-    }
-
     if (!err) {
         err = init_driver(dp, de, handle);
+
+        if (taint) {
+            erts_add_taint(dp->name_atom);
+        }
     }
 
     if (err) {