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Fix arena_prefork lock rank order for witness.

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When witness is enabled, lock rank order needs to be preserved during
prefork, not only for each arena, but also across arenas. This change
breaks arena_prefork into further stages to ensure valid rank order
across arenas. Also changed test/unit/fork to use a manual arena to
catch this case.
This commit is contained in:
Qi Wang 2017-03-08 13:00:42 -08:00 committed by Qi Wang
parent 8adab26972
commit 8721e19c04
5 changed files with 49 additions and 12 deletions
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3
include/jemalloc/internal/arena_externs.h
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@ -82,6 +82,9 @@ void arena_prefork0(tsdn_t *tsdn, arena_t *arena);
void arena_prefork1(tsdn_t *tsdn, arena_t *arena);
void arena_prefork2(tsdn_t *tsdn, arena_t *arena);
void arena_prefork3(tsdn_t *tsdn, arena_t *arena);
void arena_prefork4(tsdn_t *tsdn, arena_t *arena);
void arena_prefork5(tsdn_t *tsdn, arena_t *arena);
void arena_prefork6(tsdn_t *tsdn, arena_t *arena);
void arena_postfork_parent(tsdn_t *tsdn, arena_t *arena);
void arena_postfork_child(tsdn_t *tsdn, arena_t *arena);

3
include/jemalloc/internal/private_symbols.txt
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@ -51,6 +51,9 @@ arena_prefork0
arena_prefork1
arena_prefork2
arena_prefork3
arena_prefork4
arena_prefork5
arena_prefork6
arena_prof_accum
arena_prof_promote
arena_prof_tctx_get

22
src/arena.c
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@ -1743,29 +1743,39 @@ arena_boot(void) {
void
arena_prefork0(tsdn_t *tsdn, arena_t *arena) {
malloc_mutex_prefork(tsdn, &arena->decay.mtx);
}
void
arena_prefork1(tsdn_t *tsdn, arena_t *arena) {
if (config_stats && config_tcache) {
malloc_mutex_prefork(tsdn, &arena->tcache_ql_mtx);
}
}
void
arena_prefork1(tsdn_t *tsdn, arena_t *arena) {
arena_prefork2(tsdn_t *tsdn, arena_t *arena) {
extents_prefork(tsdn, &arena->extents_cached);
extents_prefork(tsdn, &arena->extents_retained);
}
void
arena_prefork2(tsdn_t *tsdn, arena_t *arena) {
arena_prefork3(tsdn_t *tsdn, arena_t *arena) {
malloc_mutex_prefork(tsdn, &arena->extent_freelist_mtx);
}
void
arena_prefork3(tsdn_t *tsdn, arena_t *arena) {
unsigned i;
arena_prefork4(tsdn_t *tsdn, arena_t *arena) {
base_prefork(tsdn, arena->base);
}
void
arena_prefork5(tsdn_t *tsdn, arena_t *arena) {
malloc_mutex_prefork(tsdn, &arena->large_mtx);
for (i = 0; i < NBINS; i++) {
}
void
arena_prefork6(tsdn_t *tsdn, arena_t *arena) {
for (unsigned i = 0; i < NBINS; i++) {
malloc_mutex_prefork(tsdn, &arena->bins[i].lock);
}
}

20
src/jemalloc.c
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@ -2773,7 +2773,8 @@ _malloc_prefork(void)
tcache_prefork(tsd_tsdn(tsd));
malloc_mutex_prefork(tsd_tsdn(tsd), &arenas_lock);
prof_prefork0(tsd_tsdn(tsd));
for (i = 0; i < 3; i++) {
/* Break arena prefork into stages to preserve lock order. */
for (i = 0; i < 7; i++) {
for (j = 0; j < narenas; j++) {
if ((arena = arena_get(tsd_tsdn(tsd), j, false)) !=
NULL) {
@ -2787,16 +2788,23 @@ _malloc_prefork(void)
case 2:
arena_prefork2(tsd_tsdn(tsd), arena);
break;
case 3:
arena_prefork3(tsd_tsdn(tsd), arena);
break;
case 4:
arena_prefork4(tsd_tsdn(tsd), arena);
break;
case 5:
arena_prefork5(tsd_tsdn(tsd), arena);
break;
case 6:
arena_prefork6(tsd_tsdn(tsd), arena);
break;
default: not_reached();
}
}
}
}
for (i = 0; i < narenas; i++) {
if ((arena = arena_get(tsd_tsdn(tsd), i, false)) != NULL) {
arena_prefork3(tsd_tsdn(tsd), arena);
}
}
prof_prefork1(tsd_tsdn(tsd));
}

13
test/unit/fork.c
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@ -9,6 +9,19 @@ TEST_BEGIN(test_fork) {
void *p;
pid_t pid;
/* Set up a manually managed arena for test. */
unsigned arena_ind;
size_t sz = sizeof(unsigned);
assert_d_eq(mallctl("arenas.create", (void *)&arena_ind, &sz, NULL, 0),
0, "Unexpected mallctl() failure");
/* Migrate to the new arena. */
unsigned old_arena_ind;
sz = sizeof(old_arena_ind);
assert_d_eq(mallctl("thread.arena", (void *)&old_arena_ind, &sz,
(void *)&arena_ind, sizeof(arena_ind)), 0,
"Unexpected mallctl() failure");
p = malloc(1);
assert_ptr_not_null(p, "Unexpected malloc() failure");