diff options
| -rw-r--r-- | src/common.cc | 53 |
1 files changed, 49 insertions, 4 deletions
diff --git a/src/common.cc b/src/common.cc index 972e56f..cd1e013 100644 --- a/src/common.cc +++ b/src/common.cc @@ -34,6 +34,7 @@ #include "config.h" #include "common.h" #include "system-alloc.h" +#include "base/spinlock.h" namespace tcmalloc { @@ -211,12 +212,56 @@ void SizeMap::Init() { // Metadata allocator -- keeps stats about how many bytes allocated. static uint64_t metadata_system_bytes_ = 0; +static const size_t kMetadataAllocChunkSize = 8*1024*1024; +static const size_t kMetadataBigAllocThreshold = kMetadataAllocChunkSize / 8; +// usually malloc uses larger alignments, but because metadata cannot +// have and fancy simd types, aligning on pointer size seems fine +static const size_t kMetadataAllignment = sizeof(void *); + +static char *metadata_chunk_alloc_; +static size_t metadata_chunk_avail_; + +static SpinLock metadata_alloc_lock(SpinLock::LINKER_INITIALIZED); + void* MetaDataAlloc(size_t bytes) { - void* result = TCMalloc_SystemAlloc(bytes, NULL); - if (result != NULL) { - metadata_system_bytes_ += bytes; + if (bytes >= kMetadataAllocChunkSize) { + void *rv = TCMalloc_SystemAlloc(kMetadataBigAllocThreshold, + NULL, kMetadataAllignment); + if (rv != NULL) { + metadata_system_bytes_ += bytes; + } + return rv; + } + + SpinLockHolder h(&metadata_alloc_lock); + + // the following works by essentially turning address to integer of + // log_2 kMetadataAllignment size and negating it. I.e. negated + // value + original value gets 0 and that's what we want modulo + // kMetadataAllignment. Note, we negate before masking higher bits + // off, otherwise we'd have to mask them off after negation anyways. + intptr_t alignment = -reinterpret_cast<intptr_t>(metadata_chunk_alloc_) & (kMetadataAllignment-1); + + if (metadata_chunk_avail_ < bytes + alignment) { + size_t real_size; + void *ptr = TCMalloc_SystemAlloc(kMetadataAllocChunkSize, + &real_size, kMetadataAllignment); + if (ptr == NULL) { + return NULL; + } + + metadata_chunk_alloc_ = static_cast<char *>(ptr); + metadata_chunk_avail_ = real_size; + + alignment = 0; } - return result; + + void *rv = static_cast<void *>(metadata_chunk_alloc_ + alignment); + bytes += alignment; + metadata_chunk_alloc_ += bytes; + metadata_chunk_avail_ -= bytes; + metadata_system_bytes_ += bytes; + return rv; } uint64_t metadata_system_bytes() { return metadata_system_bytes_; } |