diff options
| author | Reimer Behrends <behrends@gmail.com> | 2015-09-18 14:05:04 +0200 |
|---|---|---|
| committer | Reimer Behrends <behrends@gmail.com> | 2015-09-18 14:05:04 +0200 |
| commit | 9ea99dbf369c498215705650b111e78cd53c94da (patch) | |
| tree | 9b1d3538a3a19d0cb24760d804e0ea6b1a37f0f5 /lib/system/alloc.nim | |
| parent | d93c612067462919fb1bb6acf5cc384b7043c760 (diff) | |
| download | Nim-9ea99dbf369c498215705650b111e78cd53c94da.tar.gz | |
Add option to disable munmap() use in the allocator.
When compiling with '-d:nimAllocNoUnmap', the allocator will not attempt to return large chunks to the OS. For certain allocation behaviors, this can be a significant speedup.
Diffstat (limited to 'lib/system/alloc.nim')
| -rw-r--r-- | lib/system/alloc.nim | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/lib/system/alloc.nim b/lib/system/alloc.nim index 13a10e46f..3a1d7b666 100644 --- a/lib/system/alloc.nim +++ b/lib/system/alloc.nim @@ -27,8 +27,11 @@ sysAssert(roundup(65, 8) == 72, "roundup broken 2") # some platforms have really weird unmap behaviour: unmap(blockStart, PageSize) # really frees the whole block. Happens for Linux/PowerPC for example. Amd64 # and x86 are safe though; Windows is special because MEM_RELEASE can only be -# used with a size of 0: -const weirdUnmap = not (defined(amd64) or defined(i386)) or defined(windows) +# used with a size of 0. We also allow unmapping to be turned off with +# -d:nimAllocNoUnmap: +const doNotUnmap = not (defined(amd64) or defined(i386)) or + defined(windows) or defined(nimAllocNoUnmap) + when defined(posix): const @@ -478,7 +481,7 @@ proc freeBigChunk(a: var MemRegion, c: PBigChunk) = excl(a.chunkStarts, pageIndex(c)) c = cast[PBigChunk](le) - if c.size < ChunkOsReturn or weirdUnmap: + if c.size < ChunkOsReturn or doNotUnmap: incl(a, a.chunkStarts, pageIndex(c)) updatePrevSize(a, c, c.size) listAdd(a.freeChunksList, c) @@ -762,7 +765,7 @@ proc deallocOsPages(a: var MemRegion) = # we free every 'ordinarily' allocated page by iterating over the page bits: for p in elements(a.chunkStarts): var page = cast[PChunk](p shl PageShift) - when not weirdUnmap: + when not doNotUnmap: var size = if page.size < PageSize: PageSize else: page.size osDeallocPages(page, size) else: |