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authorSverker Eriksson <[email protected]>2015-09-16 15:28:46 +0200
committerSverker Eriksson <[email protected]>2015-10-01 19:07:26 +0200
commit5e229f3d7591b0df7d6d475065e1dc2d5273a148 (patch)
tree6ea633cb057d49e6c017732d16931105b124ff6d
parent1523be48ab4071b158412f4b06fe9c8d6ba3e73c (diff)
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erts: Fix resurrection of carriers from dc_list
Problem #1: Seems the dc_list check did end up as dead code by mistake. Solution: goto check_dc_list Problem #2: crr->cpool.max_size was set to zero for all carriers in dc_list, which meant no carriers were ever resurrected by cpool_fetch. Solution: Do not use callback 'largest_fblk_in_mbc' to set max_size as it will always return 0 (due to problem #3). Problem #3: Resurrected carriers were broken as their one free block was not linked. Solution: Link free block when fetching carrier from dc_list.
-rw-r--r--erts/emulator/beam/erl_alloc_util.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c
index 236ee35d18..3861196cfc 100644
--- a/erts/emulator/beam/erl_alloc_util.c
+++ b/erts/emulator/beam/erl_alloc_util.c
@@ -3149,7 +3149,7 @@ cpool_fetch(Allctr_t *allctr, UWord size)
cpool_entrance = sentinel;
cpdp = cpool_aint2cpd(cpool_read(&cpool_entrance->prev));
if (cpdp == sentinel)
- return NULL;
+ goto check_dc_list;
}
has_passed_sentinel = 0;
@@ -3160,18 +3160,18 @@ cpool_fetch(Allctr_t *allctr, UWord size)
if (cpool_entrance == sentinel) {
cpdp = cpool_aint2cpd(cpool_read(&cpdp->prev));
if (cpdp == sentinel)
- return NULL;
+ break;
}
i = 0; /* Last one to inspect */
}
else if (cpdp == sentinel) {
if (has_passed_sentinel) {
/* We been here before. cpool_entrance must have been removed */
- return NULL;
+ break;
}
cpdp = cpool_aint2cpd(cpool_read(&cpdp->prev));
if (cpdp == sentinel)
- return NULL;
+ break;
has_passed_sentinel = 1;
}
crr = (Carrier_t *)(((char *)cpdp) - offsetof(Carrier_t, cpool));
@@ -3195,10 +3195,12 @@ cpool_fetch(Allctr_t *allctr, UWord size)
return NULL;
}
+check_dc_list:
/* Last; check our own pending dealloc carrier list... */
crr = allctr->cpool.dc_list.last;
while (crr) {
if (erts_atomic_read_nob(&crr->cpool.max_size) >= size) {
+ Block_t* blk;
unlink_carrier(&allctr->cpool.dc_list, crr);
#ifdef ERTS_ALC_CPOOL_DEBUG
ERTS_ALC_CPOOL_ASSERT(erts_smp_atomic_xchg_nob(&crr->allctr,
@@ -3207,6 +3209,9 @@ cpool_fetch(Allctr_t *allctr, UWord size)
#else
erts_smp_atomic_set_nob(&crr->allctr, ((erts_aint_t) allctr));
#endif
+ blk = MBC_TO_FIRST_BLK(allctr, crr);
+ ASSERT(FBLK_TO_MBC(blk) == crr);
+ allctr->link_free_block(allctr, blk);
return crr;
}
crr = crr->prev;
@@ -3279,7 +3284,6 @@ schedule_dealloc_carrier(Allctr_t *allctr, Carrier_t *crr)
orig_allctr = crr->cpool.orig_allctr;
if (allctr != orig_allctr) {
- Block_t *blk = MBC_TO_FIRST_BLK(allctr, crr);
int cinit = orig_allctr->dd.ix - allctr->dd.ix;
/*
@@ -3296,6 +3300,7 @@ schedule_dealloc_carrier(Allctr_t *allctr, Carrier_t *crr)
* since the block is an mbc block that is free and last
* in the carrier.
*/
+ blk = MBC_TO_FIRST_BLK(allctr, crr);
ERTS_ALC_CPOOL_ASSERT(IS_FREE_LAST_MBC_BLK(blk));
ERTS_ALC_CPOOL_ASSERT(IS_MBC_FIRST_ABLK(allctr, blk));
@@ -3319,7 +3324,9 @@ schedule_dealloc_carrier(Allctr_t *allctr, Carrier_t *crr)
return;
}
- max_size = (erts_aint_t) allctr->largest_fblk_in_mbc(allctr, crr);
+ blk = MBC_TO_FIRST_BLK(allctr, crr);
+ ASSERT(IS_FREE_LAST_MBC_BLK(blk));
+ max_size = (erts_aint_t) MBC_FBLK_SZ(blk);
erts_atomic_set_nob(&crr->cpool.max_size, max_size);
crr->next = NULL;