erts: Rewrite memory instrumentation

This commit replaces the old memory instrumentation with a new
implementation that scans carriers instead of wrapping
erts_alloc/erts_free. The old implementation could not extract
information without halting the emulator, had considerable runtime
overhead, and the memory maps it produced were noisy and lacked
critical information.

Since the new implementation walks through existing data structures
there's no longer a need to start the emulator with special flags to
get information about carrier utilization/fragmentation. Memory
fragmentation is also easier to diagnose as it's presented on a
per-carrier basis which eliminates the need to account for "holes"
between mmap segments.

To help track allocations, each allocation can now be tagged with
what it is and who allocated it at the cost of one extra word per
allocation. This is controlled on a per-allocator basis with the
+M<S>atags option, and is enabled by default for binary_alloc and
driver_alloc (which is also used by NIFs).

1 files changed, 35 insertions, 0 deletions

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 *);