Reclaim literal area after purge has completed

10 files changed, 572 insertions, 69 deletions

diff --git a/erts/emulator/Makefile.in b/erts/emulator/Makefile.in
index 2212aed5e0..e3e0e70476 100644
--- a/erts/emulator/Makefile.in
+++ b/erts/emulator/Makefile.in
@@ -51,6 +51,7 @@ ARFLAGS=rc
 OMIT_OMIT_FP=no
 
 DIRTY_SCHEDULER_SUPPORT=@DIRTY_SCHEDULER_SUPPORT@
+NEW_PURGE_STRATEGY=@NEW_PURGE_STRATEGY@
 
 ifeq ($(TYPE),debug)
 PURIFY =
@@ -591,11 +592,8 @@ GENERATE += $(TTF_DIR)/driver_tab.c
 # 
 # This list must be consistent with PRE_LOADED_MODULES in
 # erts/preloaded/src/Makefile.
-ifeq ($(TARGET),win32)
-# On windows the preloaded objects are in a resource object.
-PRELOAD_OBJ = $(OBJDIR)/beams.$(RES_EXT)
-PRELOAD_SRC = $(TARGET)/beams.rc
-$(PRELOAD_SRC): $(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
+
+PRELOAD_BEAM =		$(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erts_code_purger.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/init.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/prim_eval.beam \
@@ -606,23 +604,19 @@ $(PRELOAD_SRC): $(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erl_prim_loader.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erlang.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erts_internal.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erl_tracer.beam
+			$(ERL_TOP)/erts/preloaded/ebin/erl_tracer.beam \
+			$(ERL_TOP)/erts/preloaded/ebin/erts_literal_area_collector.beam
+
+ifeq ($(TARGET),win32)
+# On windows the preloaded objects are in a resource object.
+PRELOAD_OBJ = $(OBJDIR)/beams.$(RES_EXT)
+PRELOAD_SRC = $(TARGET)/beams.rc
+$(PRELOAD_SRC): $(PRELOAD_BEAM)
 	$(gen_verbose)LANG=C $(PERL) utils/make_preload $(MAKE_PRELOAD_EXTRA) -rc $^ > $@
 else
 PRELOAD_OBJ = $(OBJDIR)/preload.o
 PRELOAD_SRC = $(TARGET)/preload.c
-$(PRELOAD_SRC): $(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erts_code_purger.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/init.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_eval.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_inet.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_file.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/zlib.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_zip.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erl_prim_loader.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erlang.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erts_internal.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erl_tracer.beam
+$(PRELOAD_SRC): $(PRELOAD_BEAM)
 	$(gen_verbose)LANG=C $(PERL) utils/make_preload -old $^ > $@
 endif
 
diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index badd69856e..dd37c682b1 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -176,6 +176,7 @@ atom const
 atom context_switches
 atom control
 atom copy
+atom copy_literals
 atom counters
 atom cpu
 atom cpu_timestamp
@@ -407,6 +408,7 @@ atom named_table
 atom namelist
 atom native
 atom native_addresses
+atom need_gc
 atom Neq='=/='
 atom Neqeq='/='
 atom net_kernel
diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index a94a3cc3d3..484198b339 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -37,12 +37,41 @@
 #include "erl_bits.h"
 #include "erl_thr_progress.h"
 
+Process *erts_code_purger = NULL;
+
+ErtsLiteralArea *erts_copy_literal_area = NULL;
+#ifdef ERTS_NEW_PURGE_STRATEGY
+Process *erts_literal_area_collector = NULL;
+
+typedef struct ErtsLiteralAreaRef_ ErtsLiteralAreaRef;
+struct ErtsLiteralAreaRef_ {
+    ErtsLiteralAreaRef *next;
+    ErtsLiteralArea *literal_area;
+};
+
+struct {
+    erts_smp_mtx_t mtx;
+    ErtsLiteralAreaRef *first;
+    ErtsLiteralAreaRef *last;
+} release_literal_areas;
+#endif
+
 static void set_default_trace_pattern(Eterm module);
 static Eterm check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls);
 static void delete_code(Module* modp);
 static int any_heap_ref_ptrs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size);
 static int any_heap_refs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size);
 
+void
+erts_beam_bif_load_init(void)
+{
+#ifdef ERTS_NEW_PURGE_STRATEGY
+    erts_smp_mtx_init(&release_literal_areas.mtx, "release_literal_areas");
+    release_literal_areas.first = NULL;
+    release_literal_areas.last = NULL;
+#endif
+}
+
 BIF_RETTYPE code_is_module_native_1(BIF_ALIST_1)
 {
     Module* modp;
@@ -767,6 +796,311 @@ static void hfrag_literal_copy(Eterm **hpp, ErlOffHeap *ohp,
                                Eterm *start, Eterm *end,
                                char *lit_start, Uint lit_size);
 
+#ifdef ERTS_NEW_PURGE_STRATEGY
+
+Eterm
+erts_proc_copy_literal_area(Process *c_p, int *redsp, int fcalls, int gc_allowed)
+{
+    ErtsLiteralArea *la;
+    ErtsMessage *msgp;
+    struct erl_off_heap_header* oh;
+    char *literals;
+    Uint lit_bsize;
+    ErlHeapFragment *hfrag;
+
+    la = erts_copy_literal_area;
+    if (!la)
+	return am_ok;
+
+    oh = la->off_heap;
+    literals = (char *) &la->start[0];
+    lit_bsize = (char *) la->end - literals;
+
+    /*
+     * If a literal is in the message queue we make an explicit copy of
+     * it and attach it to the heap fragment. Each message needs to be
+     * self contained, we cannot save the literal in the old_heap or
+     * any other heap than the message it self.
+     */
+
+    erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ);
+    ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p);
+    erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ);
+
+    for (msgp = c_p->msg.first; msgp; msgp = msgp->next) {
+	ErlHeapFragment *hf;
+	Uint lit_sz = 0;
+
+	*redsp += 1;
+
+	if (msgp->data.attached == ERTS_MSG_COMBINED_HFRAG)
+	    hfrag = &msgp->hfrag;
+	else if (is_value(ERL_MESSAGE_TERM(msgp)) && msgp->data.heap_frag)
+	    hfrag = msgp->data.heap_frag;
+	else
+	    continue; /* Content on heap or in external term format... */
+
+	for (hf = hfrag; hf; hf = hf->next) {
+	    lit_sz += hfrag_literal_size(&hf->mem[0], &hf->mem[hf->used_size],
+					literals, lit_bsize);
+	    *redsp += 1;
+	}
+
+	*redsp += lit_sz / 16; /* Better value needed... */
+	if (lit_sz > 0) {
+	    ErlHeapFragment *bp = new_message_buffer(lit_sz);
+	    Eterm *hp = bp->mem;
+
+	    for (hf = hfrag; hf; hf = hf->next) {
+		hfrag_literal_copy(&hp, &bp->off_heap,
+				   &hf->mem[0], &hf->mem[hf->used_size],
+				   literals, lit_bsize);
+		hfrag = hf;
+	    }
+
+	    /* link new hfrag last */
+	    ASSERT(hfrag->next == NULL);
+	    hfrag->next = bp;
+	    bp->next = NULL;
+        }
+    }
+
+    if (gc_allowed) {
+	/*
+	 * Current implementation first tests without
+	 * allowing GC, and then restarts the operation
+	 * allowing GC if it is needed. It is therfore
+	 * very likely that we will need the GC (although
+	 * this is not completely certain). We go for
+	 * the GC directly instead of scanning everything
+	 * one more time...
+	 */
+	goto literal_gc;
+    }
+
+    *redsp += 2;
+    if (any_heap_ref_ptrs(&c_p->fvalue, &c_p->fvalue+1, literals, lit_bsize)) {
+	c_p->freason = EXC_NULL;
+	c_p->fvalue = NIL;
+	c_p->ftrace = NIL;
+    }
+
+    if (any_heap_ref_ptrs(c_p->stop, c_p->hend, literals, lit_bsize))
+	goto literal_gc;
+    *redsp += 1;
+    if (any_heap_refs(c_p->heap, c_p->htop, literals, lit_bsize))
+	goto literal_gc;
+    *redsp += 1;
+    if (any_heap_refs(c_p->old_heap, c_p->old_htop, literals, lit_bsize))
+	goto literal_gc;
+
+    /* Check dictionary */
+    *redsp += 1;
+    if (c_p->dictionary) {
+	Eterm* start = ERTS_PD_START(c_p->dictionary);
+	Eterm* end = start + ERTS_PD_SIZE(c_p->dictionary);
+
+	if (any_heap_ref_ptrs(start, end, literals, lit_bsize))
+	    goto literal_gc;
+    }
+
+    /* Check heap fragments */
+    for (hfrag = c_p->mbuf; hfrag; hfrag = hfrag->next) {
+	Eterm *hp, *hp_end;
+
+	*redsp += 1;
+
+	hp = &hfrag->mem[0];
+	hp_end = &hfrag->mem[hfrag->used_size];
+	if (any_heap_refs(hp, hp_end, literals, lit_bsize))
+	    goto literal_gc;
+    }
+
+    /*
+     * Message buffer fragments (matched messages) 
+     *  - off heap lists should already have been moved into
+     *    process off heap structure.
+     *  - Check for literals
+     */
+    for (msgp = c_p->msg_frag; msgp; msgp = msgp->next) {
+	hfrag = erts_message_to_heap_frag(msgp);
+	for (; hfrag; hfrag = hfrag->next) {
+	    Eterm *hp, *hp_end;
+	    ASSERT(!check_mod_funs(c_p, &hfrag->off_heap, mod_start, mod_size));
+
+	    *redsp += 1;
+
+	    hp = &hfrag->mem[0];
+	    hp_end = &hfrag->mem[hfrag->used_size];
+
+	    if (any_heap_refs(hp, hp_end, literals, lit_bsize))
+		goto literal_gc;
+	}
+    }
+
+    return am_ok;
+
+literal_gc:
+
+    if (!gc_allowed)
+	return am_need_gc;
+
+    if (c_p->flags & F_DISABLE_GC)
+	return THE_NON_VALUE;
+
+    FLAGS(c_p) |= F_NEED_FULLSWEEP;
+
+    *redsp += erts_garbage_collect_nobump(c_p, 0, c_p->arg_reg, c_p->arity, fcalls);
+
+    erts_garbage_collect_literals(c_p, (Eterm *) literals, lit_bsize, oh);
+
+    *redsp += lit_bsize / 64; /* Need, better value... */
+
+    return am_ok;
+}
+
+static Eterm
+check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls)
+{
+    BeamInstr* start;
+    char* mod_start;
+    Uint mod_size;
+    Eterm* sp;
+    int done_gc = 0;
+    ErtsMessage *msgp;
+    ErlHeapFragment *hfrag;
+
+    /*
+     * Pick up limits for the module.
+     */
+    start = (BeamInstr*) modp->old.code_hdr;
+    mod_start = (char *) start;
+    mod_size = modp->old.code_length;
+
+    /*
+     * Check if current instruction or continuation pointer points into module.
+     */
+    if (ErtsInArea(rp->i, mod_start, mod_size)
+	|| ErtsInArea(rp->cp, mod_start, mod_size)) {
+	return am_true;
+    }
+
+    /*
+     * Check all continuation pointers stored on the stack.
+     */
+    for (sp = rp->stop; sp < STACK_START(rp); sp++) {
+	if (is_CP(*sp) && ErtsInArea(cp_val(*sp), mod_start, mod_size)) {
+	    return am_true;
+	}
+    }
+
+    /* 
+     * Check all continuation pointers stored in stackdump
+     * and clear exception stackdump if there is a pointer
+     * to the module.
+     */
+    if (rp->ftrace != NIL) {
+	struct StackTrace *s;
+	ASSERT(is_list(rp->ftrace));
+	s = (struct StackTrace *) big_val(CDR(list_val(rp->ftrace)));
+	if ((s->pc && ErtsInArea(s->pc, mod_start, mod_size)) ||
+	    (s->current && ErtsInArea(s->current, mod_start, mod_size))) {
+	    rp->freason = EXC_NULL;
+	    rp->fvalue = NIL;
+	    rp->ftrace = NIL;
+	} else {
+	    int i;
+	    for (i = 0;  i < s->depth;  i++) {
+		if (ErtsInArea(s->trace[i], mod_start, mod_size)) {
+		    rp->freason = EXC_NULL;
+		    rp->fvalue = NIL;
+		    rp->ftrace = NIL;
+		    break;
+		}
+	    }
+	}
+    }
+
+    /*
+     * Message queue can contains funs.
+     */
+
+    erts_smp_proc_lock(rp, ERTS_PROC_LOCK_MSGQ);
+    ERTS_SMP_MSGQ_MV_INQ2PRIVQ(rp);
+    erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_MSGQ);
+
+    for (msgp = rp->msg.first; msgp; msgp = msgp->next) {
+	ErlHeapFragment *hf;
+	if (msgp->data.attached == ERTS_MSG_COMBINED_HFRAG)
+	    hfrag = &msgp->hfrag;
+	else if (is_value(ERL_MESSAGE_TERM(msgp)) && msgp->data.heap_frag)
+	    hfrag = msgp->data.heap_frag;
+	else
+	    continue;
+
+	for (hf = hfrag; hf; hf = hf->next) {
+	    if (check_mod_funs(rp, &hfrag->off_heap, mod_start, mod_size))
+		return am_true;
+	}
+    }
+
+    while (1) {
+
+	/* Check heap, stack etc... */
+	if (check_mod_funs(rp, &rp->off_heap, mod_start, mod_size))
+	    goto try_gc;
+
+#ifdef DEBUG
+	/* Check heap fragments */
+	for (hfrag = rp->mbuf; hfrag; hfrag = hfrag->next) {
+	    /* Off heap lists should already have been moved into process */
+	    ASSERT(!check_mod_funs(rp, &hfrag->off_heap, mod_start, mod_size));
+	}
+
+	/*
+	 * Message buffer fragments (matched messages) 
+         *  - off heap lists should already have been moved into
+         *    process off heap structure.
+         *  - Check for literals
+	 */
+	for (msgp = rp->msg_frag; msgp; msgp = msgp->next) {
+            hfrag = erts_message_to_heap_frag(msgp);
+	    for (; hfrag; hfrag = hfrag->next) {
+		Eterm *hp, *hp_end;
+		ASSERT(!check_mod_funs(rp, &hfrag->off_heap, mod_start, mod_size));
+	    }
+	}
+#endif
+
+	return am_false;
+
+    try_gc:
+
+	if (rp->flags & F_DISABLE_GC) {
+	    /*
+	     * Cannot proceed. Process has disabled gc in order to
+	     * safely leave inconsistent data on the heap and/or
+	     * off heap lists. Need to wait for gc to be enabled
+	     * again.
+	     */ 
+	    return THE_NON_VALUE;
+	}
+
+	if (done_gc)
+	    return am_true;
+
+	if (!(flags & ERTS_CPC_ALLOW_GC))
+	    return am_aborted;
+
+	FLAGS(rp) |= F_NEED_FULLSWEEP;
+	*redsp += erts_garbage_collect_nobump(rp, 0, rp->arg_reg, rp->arity, fcalls);
+	done_gc = 1;
+    }
+
+}
+
+#else /* !ERTS_NEW_PURGE_STRATEGY, i.e, old style purge... */
+
 static Eterm
 check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls)
 {
@@ -860,8 +1194,14 @@ check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls
     ERTS_SMP_MSGQ_MV_INQ2PRIVQ(rp);
     erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_MSGQ);
 
-    literals = (char*) modp->old.code_hdr->literal_area->start;
-    lit_bsize = (char*) modp->old.code_hdr->literal_area->end - literals;
+    if (modp->old.code_hdr->literal_area) {
+	literals = (char*) modp->old.code_hdr->literal_area->start;
+	lit_bsize = (char*) modp->old.code_hdr->literal_area->end - literals;
+    }
+    else {
+	literals = NULL;
+	lit_bsize = 0;
+    }
 
     for (msgp = rp->msg.first; msgp; msgp = msgp->next) {
 	if (msgp->data.attached == ERTS_MSG_COMBINED_HFRAG)
@@ -902,12 +1242,6 @@ check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls
 	/* Check heap, stack etc... */
 	if (check_mod_funs(rp, &rp->off_heap, mod_start, mod_size))
 	    goto try_gc;
-        if (!(flags & ERTS_CPC_COPY_LITERALS)) {
-            /* Process ok. May contain old literals but we will be called
-             * again before module is purged.
-             */
-            return am_false;
-        }
 	if (any_heap_ref_ptrs(&rp->fvalue, &rp->fvalue+1, literals, lit_bsize)) {
 	    rp->freason = EXC_NULL;
 	    rp->fvalue = NIL;
@@ -1006,6 +1340,8 @@ check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls
 
 }
 
+#endif /*  !ERTS_NEW_PURGE_STRATEGY */
+
 static int
 any_heap_ref_ptrs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size)
 {
@@ -1136,12 +1472,73 @@ hfrag_literal_copy(Eterm **hpp, ErlOffHeap *ohp,
 
 #undef in_area
 
+#ifdef ERTS_NEW_PURGE_STRATEGY
+
+ErtsThrPrgrLaterOp later_literal_area_switch;
+
+static void
+complete_literal_area_switch(void *unused)
+{
+    Process *p = erts_literal_area_collector;
+    erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
+    erts_resume(p, ERTS_PROC_LOCK_STATUS);
+    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+}
+
+#endif /* ERTS_NEW_PURGE_STRATEGY */
+
+BIF_RETTYPE erts_internal_release_literal_area_switch_0(BIF_ALIST_0)
+{
+#ifndef ERTS_NEW_PURGE_STRATEGY
+    BIF_ERROR(BIF_P, EXC_NOTSUP);
+#else
+    ErtsLiteralAreaRef *la_ref;
+
+    if (BIF_P != erts_literal_area_collector)
+	BIF_ERROR(BIF_P, EXC_NOTSUP);
+
+    erts_smp_mtx_lock(&release_literal_areas.mtx);
+
+    la_ref = release_literal_areas.first;
+    if (la_ref) {
+	release_literal_areas.first = la_ref->next;
+	if (!release_literal_areas.first)
+	    release_literal_areas.last = NULL;
+    }
+
+    erts_smp_mtx_unlock(&release_literal_areas.mtx);
+
+    if (erts_copy_literal_area)
+	erts_release_literal_area(erts_copy_literal_area);
+
+    if (!la_ref) {
+	erts_copy_literal_area = NULL;
+	BIF_RET(am_false);
+    }
+
+    erts_copy_literal_area = la_ref->literal_area;
+
+    erts_free(ERTS_ALC_T_LITERAL_REF, la_ref);
+
+#ifndef ERTS_SMP
+    BIF_RET(am_true);
+#else
+    erts_schedule_thr_prgr_later_op(complete_literal_area_switch,
+				    NULL,
+				    &later_literal_area_switch);
+    erts_suspend(BIF_P, ERTS_PROC_LOCK_MAIN, NULL);
+    ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
+#endif
+
+#endif /* ERTS_NEW_PURGE_STRATEGY */
+}
+
+#ifndef ERTS_NEW_PURGE_STRATEGY
+
 #ifdef ERTS_SMP
 static void copy_literals_commit(void*);
 #endif
 
-copy_literals_t erts_clrange = {NULL, 0, THE_NON_VALUE};
-
 /* copy literals
  *
  * copy_literals.ptr = LitPtr
@@ -1157,12 +1554,19 @@ copy_literals_t erts_clrange = {NULL, 0, THE_NON_VALUE};
  *  ...
  */
 
+#endif
 
 BIF_RETTYPE erts_internal_copy_literals_2(BIF_ALIST_2)
 {
+#ifdef ERTS_NEW_PURGE_STRATEGY
+    BIF_ERROR(BIF_P, EXC_NOTSUP);
+#else
     ErtsCodeIndex code_ix;
     Eterm res = am_true;
 
+    if (BIF_P != erts_code_purger)
+	BIF_ERROR(BIF_P, EXC_NOTSUP);
+
     if (is_not_atom(BIF_ARG_1) || (am_true != BIF_ARG_2 && am_false != BIF_ARG_2)) {
         BIF_ERROR(BIF_P, BADARG);
     }
@@ -1180,22 +1584,13 @@ BIF_RETTYPE erts_internal_copy_literals_2(BIF_ALIST_2)
             res = am_false;
             goto done;
         }
-        if (erts_clrange.ptr != NULL
-            && !(BIF_P->static_flags & ERTS_STC_FLG_SYSTEM_PROC)) {
+        if (erts_copy_literal_area) {
             res = am_aborted;
             goto done;
         }
-        erts_clrange.ptr = modp->old.code_hdr->literal_area->start;
-        erts_clrange.sz  = modp->old.code_hdr->literal_area->end - erts_clrange.ptr;
-        erts_clrange.pid = BIF_P->common.id;
+	erts_copy_literal_area = modp->old.code_hdr->literal_area;
     } else if (BIF_ARG_2 == am_false) {
-        if (erts_clrange.pid != BIF_P->common.id) {
-            res = am_false;
-            goto done;
-        }
-        erts_clrange.ptr = NULL;
-        erts_clrange.sz  = 0;
-        erts_clrange.pid = THE_NON_VALUE;
+	erts_copy_literal_area = NULL;
     }
 
 #ifdef ERTS_SMP
@@ -1209,8 +1604,11 @@ BIF_RETTYPE erts_internal_copy_literals_2(BIF_ALIST_2)
 done:
     erts_release_code_write_permission();
     BIF_RET(res);
+#endif
 }
 
+#ifndef ERTS_NEW_PURGE_STRATEGY
+
 #ifdef ERTS_SMP
 static void copy_literals_commit(void* null) {
     Process* p = committer_state.stager;
@@ -1227,6 +1625,7 @@ static void copy_literals_commit(void* null) {
 }
 #endif /* ERTS_SMP */
 
+#endif
 
 /* Do the actualy module purging and return:
  * true for success
@@ -1241,6 +1640,7 @@ BIF_RETTYPE erts_internal_purge_module_1(BIF_ALIST_1)
     Module* modp;
     int is_blocking = 0;
     Eterm ret;
+    ErtsLiteralArea *literals = NULL;
 
     if (is_not_atom(BIF_ARG_1)) {
 	BIF_ERROR(BIF_P, BADARG);
@@ -1294,7 +1694,7 @@ BIF_RETTYPE erts_internal_purge_module_1(BIF_ALIST_1)
 	    erts_cleanup_funs_on_purge(code, end);
 	    beam_catches_delmod(modp->old.catches, code, modp->old.code_length,
 				code_ix);
-	    erts_release_literal_area(modp->old.code_hdr->literal_area);
+	    literals = modp->old.code_hdr->literal_area;
 	    modp->old.code_hdr->literal_area = NULL;
 	    erts_free(ERTS_ALC_T_CODE, (void *) code);
 	    modp->old.code_hdr = NULL;
@@ -1310,6 +1710,38 @@ BIF_RETTYPE erts_internal_purge_module_1(BIF_ALIST_1)
 	erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_MAIN);
     }
     erts_release_code_write_permission();
+
+#ifdef ERTS_NEW_PURGE_STRATEGY
+
+    if (literals) {
+	ErtsLiteralAreaRef *ref;
+	ref = erts_alloc(ERTS_ALC_T_LITERAL_REF,
+			 sizeof(ErtsLiteralAreaRef));
+	ref->literal_area = literals;
+	ref->next = NULL;
+	erts_smp_mtx_lock(&release_literal_areas.mtx);
+	if (release_literal_areas.last) {
+	    release_literal_areas.last->next = ref;
+	    release_literal_areas.last = ref;
+	}
+	else {
+	    release_literal_areas.first = ref;
+	    release_literal_areas.last = ref;
+	}
+	erts_smp_mtx_unlock(&release_literal_areas.mtx);
+	erts_queue_message(erts_literal_area_collector,
+			   0,
+			   erts_alloc_message(0, NULL),
+			   am_copy_literals,
+			   BIF_P->common.id);
+    }
+
+#else /* !ERTS_NEW_PURGE_STRATEGY */
+
+    erts_release_literal_area(literals);
+
+#endif
+
     return ret;
 }
 
diff --git a/erts/emulator/beam/beam_load.h b/erts/emulator/beam/beam_load.h
index 336f097f0f..d52f12e6d0 100644
--- a/erts/emulator/beam/beam_load.h
+++ b/erts/emulator/beam/beam_load.h
@@ -50,6 +50,7 @@ extern BeamInstr* em_call_error_handler;
 extern BeamInstr* em_apply_bif;
 extern BeamInstr* em_call_nif;
 
+struct ErtsLiteralArea_;
 
 /*
  * The following variables keep a sorted list of address ranges for
@@ -60,15 +61,6 @@ extern BeamInstr* em_call_nif;
 /* Total code size in bytes */
 extern Uint erts_total_code_size;
 
-typedef struct {
-    struct erl_off_heap_header *off_heap;
-    Eterm *end;
-    Eterm start[1]; /* beginning of area */
-} ErtsLiteralArea;
-
-#define ERTS_LITERAL_AREA_ALLOC_SIZE(N) \
-    (sizeof(ErtsLiteralArea) + sizeof(Eterm)*((N) - 1))
-
 typedef struct BeamCodeLineTab_ BeamCodeLineTab;
 
 /*
@@ -98,7 +90,7 @@ typedef struct beam_code_header {
     /*
      * Literal area (constant pool).
      */
-    ErtsLiteralArea *literal_area;
+    struct ErtsLiteralArea_ *literal_area;
 
     /*
      * Pointer to the on_load function (or NULL if none).
@@ -127,9 +119,11 @@ typedef struct beam_code_header {
 
 }BeamCodeHeader;
 
-void erts_release_literal_area(ErtsLiteralArea* literal_area);
+void erts_release_literal_area(struct ErtsLiteralArea_* literal_area);
 int erts_is_module_native(BeamCodeHeader* code);
 
+void erts_beam_bif_load_init(void);
+
 /*
  * Layout of the line table.
  */
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 065018514a..7ffcb26567 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -174,6 +174,8 @@ bif erts_internal:is_system_process/1
 
 bif erts_internal:system_check/1
 
+bif erts_internal:release_literal_area_switch/0
+
 # inet_db support
 bif erlang:port_set_data/2
 bif erlang:port_get_data/1
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 227fedfb69..0a4a34a174 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -367,6 +367,7 @@ type	MONITOR_LH	STANDARD	PROCESSES	monitor_lh
 type	NLINK_LH	STANDARD	PROCESSES	nlink_lh
 type	CODE		LONG_LIVED	CODE		code
 type	LITERAL		LITERAL 	CODE		literal
+type	LITERAL_REF	SHORT_LIVED	CODE		literal_area_ref
 type	DB_HEIR_DATA	STANDARD	ETS		db_heir_data
 type	DB_MS_PSDO_PROC	LONG_LIVED	ETS		db_match_pseudo_proc
 type	SCHDLR_DATA	LONG_LIVED	SYSTEM		scheduler_data
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index fbdafec4ef..788dbc3328 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -384,6 +384,7 @@ erl_init(int ncpu,
     erts_init_unicode(); /* after RE to get access to PCRE unicode */
     erts_init_external();
     erts_init_map();
+    erts_beam_bif_load_init();
     erts_delay_trap = erts_export_put(am_erlang, am_delay_trap, 2);
     erts_late_init_process();
 #if HAVE_ERTS_MSEG
@@ -2250,7 +2251,27 @@ erl_start(int argc, char **argv)
     otp_ring0_pid = erl_first_process_otp("otp_ring0", NULL, 0,
 					  boot_argc, boot_argv);
 
-    (void) erl_system_process_otp(otp_ring0_pid, "erts_code_purger");
+    {
+	/*
+	 * The erts_code_purger and the erts_literal_area_collector
+	 * system processes are *always* alive. If they terminate
+	 * they bring the whole VM down.
+	 */
+	Eterm pid;
+
+	pid = erl_system_process_otp(otp_ring0_pid, "erts_code_purger");
+	erts_code_purger = erts_proc_lookup(pid);
+	ASSERT(erts_code_purger);
+	erts_proc_inc_refc(erts_code_purger); 
+
+#ifdef ERTS_NEW_PURGE_STRATEGY
+	pid = erl_system_process_otp(otp_ring0_pid, "erts_literal_area_collector");
+	erts_literal_area_collector = erts_proc_lookup(pid);
+	ASSERT(erts_literal_area_collector);
+	erts_proc_inc_refc(erts_literal_area_collector);
+#endif
+
+    }
 
 #ifdef ERTS_SMP
     erts_start_schedulers();
@@ -2350,14 +2371,15 @@ erts_exit_vv(int n, int flush_async, char *fmt, va_list args1, va_list args2)
     if (erts_mtrace_enabled)
 	erts_mtrace_exit((Uint32) n);
 
+    if (fmt != NULL && *fmt != '\0')
+	  erl_error(fmt, args2);	/* Print error message. */
+
     /* Produce an Erlang core dump if error */
     if (((n == ERTS_ERROR_EXIT && erts_no_crash_dump == 0) || n == ERTS_DUMP_EXIT)
 	&& erts_initialized) {
 	erl_crash_dump_v((char*) NULL, 0, fmt, args1);
     }
 
-    if (fmt != NULL && *fmt != '\0')
-	  erl_error(fmt, args2);	/* Print error message. */
     sys_tty_reset(n);
 
     if (n == ERTS_INTR_EXIT)
diff --git a/erts/emulator/beam/erl_lock_check.c b/erts/emulator/beam/erl_lock_check.c
index 39c0617143..4192cf389f 100644
--- a/erts/emulator/beam/erl_lock_check.c
+++ b/erts/emulator/beam/erl_lock_check.c
@@ -112,6 +112,9 @@ static erts_lc_lock_order_t erts_lock_order[] = {
     {	"export_tab",				NULL			},
     {	"fun_tab",				NULL			},
     {	"environ",				NULL			},
+#ifdef ERTS_NEW_PURGE_STRATEGY
+    {	"release_literal_areas",		NULL			},
+#endif
 #endif
     {	"efile_drv",				"address"		},
     {	"drv_ev_state_grow",			NULL,   		},
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 66f22979ad..42c30b935e 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -448,6 +448,9 @@ int erts_system_profile_ts_type = ERTS_TRACE_FLG_NOW_TIMESTAMP;
 typedef enum {
     ERTS_PSTT_GC,	/* Garbage Collect */
     ERTS_PSTT_CPC,	/* Check Process Code */
+#ifdef ERTS_NEW_PURGE_STRATEGY
+    ERTS_PSTT_CLA,	/* Copy Literal Area */
+#endif
     ERTS_PSTT_COHMQ,    /* Change off heap message queue */
     ERTS_PSTT_FTMQ      /* Flush trace msg queue */
 } ErtsProcSysTaskType;
@@ -10393,6 +10396,27 @@ execute_sys_tasks(Process *c_p, erts_aint32_t *statep, int in_reds)
 	    }
 	    break;
         }
+#ifdef ERTS_NEW_PURGE_STRATEGY
+	case ERTS_PSTT_CLA: {
+	    int fcalls;
+            int cla_reds = 0;
+	    if (!ERTS_PROC_GET_SAVED_CALLS_BUF(c_p))
+		fcalls = reds;
+	    else
+		fcalls = reds - CONTEXT_REDS;
+	    st_res = erts_proc_copy_literal_area(c_p,
+						 &cla_reds,
+						 fcalls,
+						 st->arg[0] == am_true);
+            reds -= cla_reds;
+	    if (is_non_value(st_res)) {
+		/* Needed gc, but gc was disabled */
+		save_gc_task(c_p, st, st_prio);
+		st = NULL;
+	    }
+	    break;
+        }
+#endif
 	case ERTS_PSTT_COHMQ:
 	    reds -= erts_complete_off_heap_message_queue_change(c_p);
 	    st_res = am_true;
@@ -10443,14 +10467,15 @@ cleanup_sys_tasks(Process *c_p, erts_aint32_t in_state, int in_reds)
 
 	switch (st->type) {
 	case ERTS_PSTT_GC:
-	    st_res = am_false;
-	    break;
 	case ERTS_PSTT_CPC:
-	    st_res = am_false;
-	    break;
 	case ERTS_PSTT_COHMQ:
 	    st_res = am_false;
 	    break;
+#ifdef ERTS_NEW_PURGE_STRATEGY
+	case ERTS_PSTT_CLA:
+	    st_res = am_ok;
+	    break;
+#endif
 #ifdef ERTS_SMP
         case ERTS_PSTT_FTMQ:
 	    reds -= erts_flush_trace_messages(c_p, ERTS_PROC_LOCK_MAIN);
@@ -10572,6 +10597,17 @@ erts_internal_request_system_task_3(BIF_ALIST_3)
 	    goto noproc;
 	break;
 
+#ifdef ERTS_NEW_PURGE_STRATEGY
+    case am_copy_literals:
+	if (st->arg[0] != am_true && st->arg[0] != am_false)
+	    goto badarg;
+	st->type = ERTS_PSTT_CLA;
+	noproc_res = am_ok;
+	if (!rp)
+	    goto noproc;
+	break;
+#endif
+
     default:
 	goto badarg;
     }
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index f3d4ac56cd..00dfc421d5 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -999,17 +999,27 @@ Eterm erl_is_function(Process* p, Eterm arg1, Eterm arg2);
 
 /* beam_bif_load.c */
 #define ERTS_CPC_ALLOW_GC      (1 << 0)
-#define ERTS_CPC_COPY_LITERALS (1 << 1)
-#define ERTS_CPC_ALL           (ERTS_CPC_ALLOW_GC | ERTS_CPC_COPY_LITERALS)
+#define ERTS_CPC_ALL           ERTS_CPC_ALLOW_GC
 Eterm erts_check_process_code(Process *c_p, Eterm module, Uint flags, int *redsp, int fcalls);
+#ifdef ERTS_NEW_PURGE_STRATEGY
+Eterm erts_proc_copy_literal_area(Process *c_p, int *redsp, int fcalls, int gc_allowed);
+#endif
 
-typedef struct {
-    Eterm *ptr;
-    Uint   sz;
-    Eterm pid;
-} copy_literals_t;
+typedef struct ErtsLiteralArea_ {
+    struct erl_off_heap_header *off_heap;
+    Eterm *end;
+    Eterm start[1]; /* beginning of area */
+} ErtsLiteralArea;
 
-extern copy_literals_t erts_clrange;
+#define ERTS_LITERAL_AREA_ALLOC_SIZE(N) \
+    (sizeof(ErtsLiteralArea) + sizeof(Eterm)*((N) - 1))
+
+extern ErtsLiteralArea *erts_copy_literal_area;
+#ifdef ERTS_NEW_PURGE_STRATEGY
+extern Process *erts_literal_area_collector;
+#endif
+
+extern Process *erts_code_purger;
 
 /* beam_load.c */
 typedef struct {
@@ -1092,12 +1102,19 @@ typedef struct {
 
 #define INITIALIZE_SHCOPY(info)                         \
 do {                                                    \
+    ErtsLiteralArea *larea__ = erts_copy_literal_area;	\
     info.queue_start = info.queue_default;              \
     info.bitstore_start = info.bitstore_default;        \
     info.shtable_start = info.shtable_default;          \
     info.literal_size = 0;                              \
-    info.range_ptr = erts_clrange.ptr;                  \
-    info.range_sz  = erts_clrange.sz;                   \
+    if (larea__) {					\
+	info.range_ptr = &larea__->start[0];		\
+	info.range_sz = larea__->end - info.range_ptr;	\
+    }							\
+    else {						\
+	info.range_ptr = NULL;				\
+	info.range_sz = 0;				\
+    }							\
 } while(0)
 
 #define DESTROY_SHCOPY(info)                                            \