RepoMirrors
/
gperftools
mirror of https://github.com/gperftools/gperftools
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

don't round up sizes for large allocation when sampling 

This closes #723.

Since rounding up prior to sampling is introducing possibility of
arithmetic overflow, we're just not doing it.

It introduces some error (up to 4k), but since we're dealing with at
least 256k allocations, we're fine.
This commit is contained in:
Aliaksey Kandratsenka 2016-02-21 19:26:37 -08:00
parent 4f3410e759
commit 7dd4af6536
1 changed files with 6 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
src/tcmalloc.cc
View File

@ -1154,8 +1154,13 @@ inline void* do_malloc_pages(ThreadCache* heap, size_t size) {
bool report_large;
Length num_pages = tcmalloc::pages(size);
size = num_pages << kPageShift;
// NOTE: we're passing original size here as opposed to rounded-up
// size as we do in do_malloc_small. The difference is small here
// (at most 4k out of at least 256k). And not rounding up saves us
// from possibility of overflow, which rounding up could produce.
//
// See https://github.com/gperftools/gperftools/issues/723
if (heap->SampleAllocation(size)) {
result = DoSampledAllocation(size);