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authorSverker Eriksson <[email protected]>2018-05-24 18:36:13 +0200
committerSverker Eriksson <[email protected]>2018-07-05 11:34:21 +0200
commit00096d4cda052f369bc5b9f8a0939d9fa7873a9b (patch)
tree977a0d3866184447903b25446c41b3ab8f4b1c12 /erts/emulator
parenta8da98f69b252aba6e6f31cd7217936204be45df (diff)
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erts: Simplify cpool_fetch
and avoid faulty bumps of 'entrance_removed' stat.
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/beam/erl_alloc_util.c36
1 files changed, 13 insertions, 23 deletions
diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c
index 1c95385649..f0e764c9a7 100644
--- a/erts/emulator/beam/erl_alloc_util.c
+++ b/erts/emulator/beam/erl_alloc_util.c
@@ -3370,8 +3370,7 @@ cpool_delete(Allctr_t *allctr, Allctr_t *prev_allctr, Carrier_t *crr)
static Carrier_t *
cpool_fetch(Allctr_t *allctr, UWord size)
{
- enum { IGNORANT, HAS_SEEN_SENTINEL, THE_LAST_ONE } loop_state;
- int i;
+ int i, seen_sentinel;
Carrier_t *crr;
Carrier_t *reinsert_crr = NULL;
ErtsAlcCPoolData_t *cpdp;
@@ -3485,43 +3484,34 @@ cpool_fetch(Allctr_t *allctr, UWord size)
/*
* We saw a pooled carried above, use it as entrance into the pool
*/
- cpdp = cpool_entrance;
}
else {
/*
- * No pooled carried seen above. Start search at cpool sentinel,
+ * No pooled carrier seen above. Start search at cpool sentinel,
* but begin by passing one element before trying to fetch.
* This in order to avoid contention with threads inserting elements.
*/
- cpool_entrance = sentinel;
- cpdp = cpool_aint2cpd(cpool_read(&cpool_entrance->prev));
- if (cpdp == sentinel)
+ cpool_entrance = cpool_aint2cpd(cpool_read(&sentinel->prev));
+ if (cpool_entrance == sentinel)
goto check_dc_list;
}
- loop_state = IGNORANT;
+ cpdp = cpool_entrance;
+ seen_sentinel = 0;
do {
erts_aint_t exp;
cpdp = cpool_aint2cpd(cpool_read(&cpdp->prev));
- if (cpdp == cpool_entrance) {
- if (cpool_entrance == sentinel) {
- cpdp = cpool_aint2cpd(cpool_read(&cpdp->prev));
- if (cpdp == sentinel)
- break;
- }
- loop_state = THE_LAST_ONE;
- }
- else if (cpdp == sentinel) {
- if (loop_state == HAS_SEEN_SENTINEL) {
+ if (cpdp == sentinel) {
+ if (seen_sentinel) {
/* We been here before. cpool_entrance must have been removed */
INC_CC(allctr->cpool.stat.entrance_removed);
break;
}
- cpdp = cpool_aint2cpd(cpool_read(&cpdp->prev));
- if (cpdp == sentinel)
- break;
- loop_state = HAS_SEEN_SENTINEL;
+ seen_sentinel = 1;
+ continue;
}
+ ASSERT(cpdp != cpool_entrance || seen_sentinel);
+
crr = ErtsContainerStruct(cpdp, Carrier_t, cpool);
exp = erts_atomic_read_rb(&crr->allctr);
@@ -3554,7 +3544,7 @@ cpool_fetch(Allctr_t *allctr, UWord size)
INC_CC(allctr->cpool.stat.fail_shared);
return NULL;
}
- }while (loop_state != THE_LAST_ONE);
+ }while (cpdp != cpool_entrance);
check_dc_list:
/* Last; check our own pending dealloc carrier list... */