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Diffstat (limited to 'absl/base/internal/low_level_alloc.cc')
-rw-r--r--absl/base/internal/low_level_alloc.cc89
1 files changed, 50 insertions, 39 deletions
diff --git a/absl/base/internal/low_level_alloc.cc b/absl/base/internal/low_level_alloc.cc
index 662167b0..6d2cfeac 100644
--- a/absl/base/internal/low_level_alloc.cc
+++ b/absl/base/internal/low_level_alloc.cc
@@ -42,25 +42,25 @@
#include <windows.h>
#endif
+#ifdef __linux__
+#include <sys/prctl.h>
+#endif
+
#include <string.h>
+
#include <algorithm>
#include <atomic>
#include <cerrno>
#include <cstddef>
-#include <new> // for placement-new
+#include <new> // for placement-new
#include "absl/base/dynamic_annotations.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/spinlock.h"
-// MAP_ANONYMOUS
-#if defined(__APPLE__)
-// For mmap, Linux defines both MAP_ANONYMOUS and MAP_ANON and says MAP_ANON is
-// deprecated. In Darwin, MAP_ANON is all there is.
-#if !defined MAP_ANONYMOUS
+#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON
-#endif // !MAP_ANONYMOUS
-#endif // __APPLE__
+#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
@@ -122,7 +122,7 @@ static int IntLog2(size_t size, size_t base) {
static int Random(uint32_t *state) {
uint32_t r = *state;
int result = 1;
- while ((((r = r*1103515245 + 12345) >> 30) & 1) == 0) {
+ while ((((r = r * 1103515245 + 12345) >> 30) & 1) == 0) {
result++;
}
*state = r;
@@ -144,7 +144,7 @@ static int LLA_SkiplistLevels(size_t size, size_t base, uint32_t *random) {
size_t max_fit = (size - offsetof(AllocList, next)) / sizeof(AllocList *);
int level = IntLog2(size, base) + (random != nullptr ? Random(random) : 1);
if (static_cast<size_t>(level) > max_fit) level = static_cast<int>(max_fit);
- if (level > kMaxLevel-1) level = kMaxLevel - 1;
+ if (level > kMaxLevel - 1) level = kMaxLevel - 1;
ABSL_RAW_CHECK(level >= 1, "block not big enough for even one level");
return level;
}
@@ -153,8 +153,8 @@ static int LLA_SkiplistLevels(size_t size, size_t base, uint32_t *random) {
// For 0 <= i < head->levels, set prev[i] to "no_greater", where no_greater
// points to the last element at level i in the AllocList less than *e, or is
// head if no such element exists.
-static AllocList *LLA_SkiplistSearch(AllocList *head,
- AllocList *e, AllocList **prev) {
+static AllocList *LLA_SkiplistSearch(AllocList *head, AllocList *e,
+ AllocList **prev) {
AllocList *p = head;
for (int level = head->levels - 1; level >= 0; level--) {
for (AllocList *n; (n = p->next[level]) != nullptr && n < e; p = n) {
@@ -190,7 +190,7 @@ static void LLA_SkiplistDelete(AllocList *head, AllocList *e,
prev[i]->next[i] = e->next[i];
}
while (head->levels > 0 && head->next[head->levels - 1] == nullptr) {
- head->levels--; // reduce head->levels if level unused
+ head->levels--; // reduce head->levels if level unused
}
}
@@ -249,9 +249,9 @@ void CreateGlobalArenas() {
// Returns a global arena that does not call into hooks. Used by NewArena()
// when kCallMallocHook is not set.
-LowLevelAlloc::Arena* UnhookedArena() {
+LowLevelAlloc::Arena *UnhookedArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
- return reinterpret_cast<LowLevelAlloc::Arena*>(&unhooked_arena_storage);
+ return reinterpret_cast<LowLevelAlloc::Arena *>(&unhooked_arena_storage);
}
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
@@ -269,7 +269,7 @@ LowLevelAlloc::Arena *UnhookedAsyncSigSafeArena() {
// Returns the default arena, as used by LowLevelAlloc::Alloc() and friends.
LowLevelAlloc::Arena *LowLevelAlloc::DefaultArena() {
base_internal::LowLevelCallOnce(&create_globals_once, CreateGlobalArenas);
- return reinterpret_cast<LowLevelAlloc::Arena*>(&default_arena_storage);
+ return reinterpret_cast<LowLevelAlloc::Arena *>(&default_arena_storage);
}
// magic numbers to identify allocated and unallocated blocks
@@ -356,8 +356,7 @@ LowLevelAlloc::Arena::Arena(uint32_t flags_value)
min_size(2 * round_up),
random(0) {
freelist.header.size = 0;
- freelist.header.magic =
- Magic(kMagicUnallocated, &freelist.header);
+ freelist.header.magic = Magic(kMagicUnallocated, &freelist.header);
freelist.header.arena = this;
freelist.levels = 0;
memset(freelist.next, 0, sizeof(freelist.next));
@@ -375,7 +374,7 @@ LowLevelAlloc::Arena *LowLevelAlloc::NewArena(uint32_t flags) {
meta_data_arena = UnhookedArena();
}
Arena *result =
- new (AllocWithArena(sizeof (*result), meta_data_arena)) Arena(flags);
+ new (AllocWithArena(sizeof(*result), meta_data_arena)) Arena(flags);
return result;
}
@@ -480,8 +479,8 @@ static void Coalesce(AllocList *a) {
AllocList *prev[kMaxLevel];
LLA_SkiplistDelete(&arena->freelist, n, prev);
LLA_SkiplistDelete(&arena->freelist, a, prev);
- a->levels = LLA_SkiplistLevels(a->header.size, arena->min_size,
- &arena->random);
+ a->levels =
+ LLA_SkiplistLevels(a->header.size, arena->min_size, &arena->random);
LLA_SkiplistInsert(&arena->freelist, a, prev);
}
}
@@ -489,27 +488,27 @@ static void Coalesce(AllocList *a) {
// Adds block at location "v" to the free list
// L >= arena->mu
static void AddToFreelist(void *v, LowLevelAlloc::Arena *arena) {
- AllocList *f = reinterpret_cast<AllocList *>(
- reinterpret_cast<char *>(v) - sizeof (f->header));
+ AllocList *f = reinterpret_cast<AllocList *>(reinterpret_cast<char *>(v) -
+ sizeof(f->header));
ABSL_RAW_CHECK(f->header.magic == Magic(kMagicAllocated, &f->header),
"bad magic number in AddToFreelist()");
ABSL_RAW_CHECK(f->header.arena == arena,
"bad arena pointer in AddToFreelist()");
- f->levels = LLA_SkiplistLevels(f->header.size, arena->min_size,
- &arena->random);
+ f->levels =
+ LLA_SkiplistLevels(f->header.size, arena->min_size, &arena->random);
AllocList *prev[kMaxLevel];
LLA_SkiplistInsert(&arena->freelist, f, prev);
f->header.magic = Magic(kMagicUnallocated, &f->header);
- Coalesce(f); // maybe coalesce with successor
- Coalesce(prev[0]); // maybe coalesce with predecessor
+ Coalesce(f); // maybe coalesce with successor
+ Coalesce(prev[0]); // maybe coalesce with predecessor
}
// Frees storage allocated by LowLevelAlloc::Alloc().
// L < arena->mu
void LowLevelAlloc::Free(void *v) {
if (v != nullptr) {
- AllocList *f = reinterpret_cast<AllocList *>(
- reinterpret_cast<char *>(v) - sizeof (f->header));
+ AllocList *f = reinterpret_cast<AllocList *>(reinterpret_cast<char *>(v) -
+ sizeof(f->header));
LowLevelAlloc::Arena *arena = f->header.arena;
ArenaLock section(arena);
AddToFreelist(v, arena);
@@ -524,21 +523,21 @@ void LowLevelAlloc::Free(void *v) {
static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
void *result = nullptr;
if (request != 0) {
- AllocList *s; // will point to region that satisfies request
+ AllocList *s; // will point to region that satisfies request
ArenaLock section(arena);
// round up with header
- size_t req_rnd = RoundUp(CheckedAdd(request, sizeof (s->header)),
- arena->round_up);
- for (;;) { // loop until we find a suitable region
+ size_t req_rnd =
+ RoundUp(CheckedAdd(request, sizeof(s->header)), arena->round_up);
+ for (;;) { // loop until we find a suitable region
// find the minimum levels that a block of this size must have
int i = LLA_SkiplistLevels(req_rnd, arena->min_size, nullptr) - 1;
- if (i < arena->freelist.levels) { // potential blocks exist
+ if (i < arena->freelist.levels) { // potential blocks exist
AllocList *before = &arena->freelist; // predecessor of s
while ((s = Next(i, before, arena)) != nullptr &&
s->header.size < req_rnd) {
before = s;
}
- if (s != nullptr) { // we found a region
+ if (s != nullptr) { // we found a region
break;
}
}
@@ -550,7 +549,7 @@ static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
size_t new_pages_size = RoundUp(req_rnd, arena->pagesize * 16);
void *new_pages;
#ifdef _WIN32
- new_pages = VirtualAlloc(0, new_pages_size,
+ new_pages = VirtualAlloc(nullptr, new_pages_size,
MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
ABSL_RAW_CHECK(new_pages != nullptr, "VirtualAlloc failed");
#else
@@ -570,6 +569,18 @@ static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
ABSL_RAW_LOG(FATAL, "mmap error: %d", errno);
}
+#ifdef __linux__
+#if defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME)
+ // Attempt to name the allocated address range in /proc/$PID/smaps on
+ // Linux.
+ //
+ // This invocation of prctl() may fail if the Linux kernel was not
+ // configured with the CONFIG_ANON_VMA_NAME option. This is OK since
+ // the naming of arenas is primarily a debugging aid.
+ prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, new_pages, new_pages_size,
+ "absl");
+#endif
+#endif // __linux__
#endif // _WIN32
arena->mu.Lock();
s = reinterpret_cast<AllocList *>(new_pages);
@@ -580,12 +591,12 @@ static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
AddToFreelist(&s->levels, arena); // insert new region into free list
}
AllocList *prev[kMaxLevel];
- LLA_SkiplistDelete(&arena->freelist, s, prev); // remove from free list
+ LLA_SkiplistDelete(&arena->freelist, s, prev); // remove from free list
// s points to the first free region that's big enough
if (CheckedAdd(req_rnd, arena->min_size) <= s->header.size) {
// big enough to split
- AllocList *n = reinterpret_cast<AllocList *>
- (req_rnd + reinterpret_cast<char *>(s));
+ AllocList *n =
+ reinterpret_cast<AllocList *>(req_rnd + reinterpret_cast<char *>(s));
n->header.size = s->header.size - req_rnd;
n->header.magic = Magic(kMagicAllocated, &n->header);
n->header.arena = arena;
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-17 23:15:02 +0000