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authorBjörn-Egil Dahlberg <[email protected]>2016-05-18 19:38:47 +0200
committerBjörn-Egil Dahlberg <[email protected]>2016-05-20 18:22:45 +0200
commit9effc6a6c52d9c492925c4271743d06d68d04bcb (patch)
tree1fd1cf8c33b50dbca7a0ba5d2d024b05257c5c9f /erts/emulator/beam
parent949f1d3a807e3bb095668fac4bfc4624fea2e34e (diff)
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erts: Copy literals in messages on module purge
During check process code, explicitly copy all referenced literals in a message (in the private queue) to a heap fragment and attach it to the message reference. Not all types of message communication does an explicit copy of a literal and this needs to be taken care of before a module is purged.
Diffstat (limited to 'erts/emulator/beam')
-rw-r--r--erts/emulator/beam/beam_bif_load.c136
1 files changed, 118 insertions, 18 deletions
diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index 40d44dda4c..8b5d1a0391 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -762,6 +762,11 @@ check_mod_funs(Process *p, ErlOffHeap *off_heap, char *area, size_t area_size)
return 0;
}
+static Uint hfrag_literal_size(Eterm* start, Eterm* end,
+ char* lit_start, Uint lit_size);
+static void hfrag_literal_copy(Eterm **hpp, ErlOffHeap *ohp,
+ Eterm *start, Eterm *end,
+ char *lit_start, Uint lit_size);
static Eterm
check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls)
@@ -842,9 +847,14 @@ check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls
}
/*
- * Message queue can contains funs, but (at least currently) no
+ * Message queue can contains funs, and may contain
* literals. If we got references to this module from the message
- * queue, a GC cannot remove these...
+ * queue.
+ *
+ * If a literal is in the message queue we maka an explicit copy of
+ * 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(rp, ERTS_PROC_LOCK_MSGQ);
@@ -861,15 +871,31 @@ check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls
hfrag = msgp->data.heap_frag;
else
continue;
- for (; hfrag; hfrag = hfrag->next) {
- if (check_mod_funs(rp, &hfrag->off_heap, mod_start, mod_size))
- return am_true;
- /* Should not contain any literals... */
- ASSERT(!any_heap_refs(&hfrag->mem[0],
- &hfrag->mem[hfrag->used_size],
- literals,
- lit_bsize));
- }
+ {
+ ErlHeapFragment *hf;
+ Uint lit_sz;
+ for (hf=hfrag; hf; hf = hf->next) {
+ if (check_mod_funs(rp, &hfrag->off_heap, mod_start, mod_size))
+ return am_true;
+ lit_sz = hfrag_literal_size(&hf->mem[0], &hf->mem[hf->used_size],
+ literals, lit_bsize);
+ }
+ 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;
+ }
+ }
}
while (1) {
@@ -916,11 +942,11 @@ check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls
goto try_literal_gc;
}
-#ifdef DEBUG
/*
- * Message buffer fragments should not have any references
- * to literals, and off heap lists should already have
- * been moved into process off heap structure.
+ * 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) {
if (msgp->data.attached == ERTS_MSG_COMBINED_HFRAG)
@@ -933,12 +959,12 @@ check_process_code(Process* rp, Module* modp, Uint flags, int *redsp, int fcalls
hp = &hfrag->mem[0];
hp_end = &hfrag->mem[hfrag->used_size];
- ASSERT(!any_heap_refs(hp, hp_end, literals, lit_bsize));
+
+ if (any_heap_refs(hp, hp_end, literals, lit_bsize))
+ goto try_literal_gc;
}
}
-#endif
-
return am_false;
try_literal_gc:
@@ -1038,6 +1064,80 @@ any_heap_refs(Eterm* start, Eterm* end, char* mod_start, Uint mod_size)
return 0;
}
+static Uint
+hfrag_literal_size(Eterm* start, Eterm* end, char* lit_start, Uint lit_size)
+{
+ Eterm* p;
+ Eterm val;
+ Uint sz = 0;
+
+ for (p = start; p < end; p++) {
+ val = *p;
+ switch (primary_tag(val)) {
+ case TAG_PRIMARY_BOXED:
+ case TAG_PRIMARY_LIST:
+ if (ErtsInArea(val, lit_start, lit_size)) {
+ sz += size_object(val);
+ }
+ break;
+ case TAG_PRIMARY_HEADER:
+ if (!header_is_transparent(val)) {
+ Eterm* new_p;
+ if (header_is_bin_matchstate(val)) {
+ ErlBinMatchState *ms = (ErlBinMatchState*) p;
+ ErlBinMatchBuffer *mb = &(ms->mb);
+ if (ErtsInArea(mb->orig, lit_start, lit_size)) {
+ sz += size_object(mb->orig);
+ }
+ }
+ new_p = p + thing_arityval(val);
+ ASSERT(start <= new_p && new_p < end);
+ p = new_p;
+ }
+ }
+ }
+ return sz;
+}
+
+static void
+hfrag_literal_copy(Eterm **hpp, ErlOffHeap *ohp,
+ Eterm *start, Eterm *end,
+ char *lit_start, Uint lit_size) {
+ Eterm* p;
+ Eterm val;
+ Uint sz;
+
+ for (p = start; p < end; p++) {
+ val = *p;
+ switch (primary_tag(val)) {
+ case TAG_PRIMARY_BOXED:
+ case TAG_PRIMARY_LIST:
+ if (ErtsInArea(val, lit_start, lit_size)) {
+ sz = size_object(val);
+ val = copy_struct(val, sz, hpp, ohp);
+ *p = val;
+ }
+ break;
+ case TAG_PRIMARY_HEADER:
+ if (!header_is_transparent(val)) {
+ Eterm* new_p;
+ /* matchstate in message, not possible. */
+ if (header_is_bin_matchstate(val)) {
+ ErlBinMatchState *ms = (ErlBinMatchState*) p;
+ ErlBinMatchBuffer *mb = &(ms->mb);
+ if (ErtsInArea(mb->orig, lit_start, lit_size)) {
+ sz = size_object(mb->orig);
+ mb->orig = copy_struct(mb->orig, sz, hpp, ohp);
+ }
+ }
+ new_p = p + thing_arityval(val);
+ ASSERT(start <= new_p && new_p < end);
+ p = new_p;
+ }
+ }
+ }
+}
+
#undef in_area
#ifdef ERTS_SMP