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Move junking out of arena/tcache code.

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This is debug only and we keep it off the fast path.  Moving it here simplifies
the internal logic.

This never tries to junk on regions that were shrunk via xallocx.  I think this
is fine for two reasons:
- The shrunk-with-xallocx case is rare.
- We don't always do that anyway before this diff (it depends on the opt
  settings and extent hooks in effect).
This commit is contained in:
David Goldblatt
2020-02-28 11:37:39 -08:00
committed by David Goldblatt
parent b428dceeaf
commit 79f1ee2fc0
9 changed files with 249 additions and 248 deletions
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62
src/jemalloc.c
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@@ -81,6 +81,24 @@ const char *zero_realloc_mode_names[] = {
"abort",
};
/*
* These are the documented values for junk fill debugging facilities -- see the
* man page.
*/
static const uint8_t junk_alloc_byte = 0xa5;
static const uint8_t junk_free_byte = 0x5a;
static void default_junk_alloc(void *ptr, size_t usize) {
memset(ptr, junk_alloc_byte, usize);
}
static void default_junk_free(void *ptr, size_t usize) {
memset(ptr, junk_free_byte, usize);
}
void (*junk_alloc_callback)(void *ptr, size_t size) = &default_junk_alloc;
void (*junk_free_callback)(void *ptr, size_t size) = &default_junk_free;
bool opt_utrace = false;
bool opt_xmalloc = false;
bool opt_zero = false;
@@ -2210,6 +2228,14 @@ imalloc_body(static_opts_t *sopts, dynamic_opts_t *dopts, tsd_t *tsd) {
assert(usize == isalloc(tsd_tsdn(tsd), allocation));
if (config_fill && sopts->slow && !dopts->zero) {
if (unlikely(opt_junk_alloc)) {
junk_alloc_callback(allocation, usize);
} else if (unlikely(opt_zero)) {
memset(allocation, 0, usize);
}
}
if (sopts->slow) {
UTRACE(0, size, allocation);
}
@@ -2582,6 +2608,9 @@ ifree(tsd_t *tsd, void *ptr, tcache_t *tcache, bool slow_path) {
idalloctm(tsd_tsdn(tsd), ptr, tcache, &alloc_ctx, false,
false);
} else {
if (config_fill && slow_path && opt_junk_free) {
junk_free_callback(ptr, usize);
}
idalloctm(tsd_tsdn(tsd), ptr, tcache, &alloc_ctx, false,
true);
}
@@ -2648,6 +2677,9 @@ isfree(tsd_t *tsd, void *ptr, size_t usize, tcache_t *tcache, bool slow_path) {
isdalloct(tsd_tsdn(tsd), ptr, usize, tcache, &alloc_ctx,
false);
} else {
if (config_fill && slow_path && opt_junk_free) {
junk_free_callback(ptr, usize);
}
isdalloct(tsd_tsdn(tsd), ptr, usize, tcache, &alloc_ctx,
true);
}
@@ -2745,6 +2777,14 @@ bool free_fastpath(void *ptr, size_t size, bool size_hint) {
tcache_t *tcache = tsd_tcachep_get(tsd);
cache_bin_t *bin = tcache_small_bin_get(tcache, alloc_ctx.szind);
/*
* If junking were enabled, this is where we would do it. It's not
* though, since we ensured above that we're on the fast path. Assert
* that to double-check.
*/
assert(!opt_junk_free);
if (!cache_bin_dalloc_easy(bin, ptr)) {
return false;
}
@@ -3180,6 +3220,16 @@ do_rallocx(void *ptr, size_t size, int flags, bool is_realloc) {
UTRACE(ptr, size, p);
check_entry_exit_locking(tsd_tsdn(tsd));
if (config_fill && malloc_slow && !zero && usize > old_usize) {
size_t excess_len = usize - old_usize;
void *excess_start = (void *)((uintptr_t)p + old_usize);
if (unlikely(opt_junk_alloc)) {
junk_alloc_callback(excess_start, excess_len);
} else if (unlikely(opt_zero)) {
memset(excess_start, 0, excess_len);
}
}
return p;
label_oom:
if (config_xmalloc && unlikely(opt_xmalloc)) {
@@ -3465,6 +3515,18 @@ je_xallocx(void *ptr, size_t size, size_t extra, int flags) {
goto label_not_resized;
}
thread_dalloc_event(tsd, old_usize);
if (config_fill && malloc_slow) {
if (usize > old_usize && !zero) {
size_t excess_len = usize - old_usize;
void *excess_start = (void *)((uintptr_t)ptr + old_usize);
if (unlikely(opt_junk_alloc)) {
junk_alloc_callback(excess_start, excess_len);
} else if (unlikely(opt_zero)) {
memset(excess_start, 0, excess_len);
}
}
}
label_not_resized:
if (unlikely(!tsd_fast(tsd))) {
uintptr_t args[4] = {(uintptr_t)ptr, size, extra, flags};