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| author | Keith Bostic <keith@wiredtiger.com> | 2013-05-13 09:01:43 -0400 |
|---|---|---|
| committer | Keith Bostic <keith@wiredtiger.com> | 2013-05-13 09:01:43 -0400 |
| commit | 014499da26d35f8c72279f3c37b3c467dfc910aa (patch) | |
| tree | ee2b91a68e555c04fd3e2e97e386203347d6143d | |
| parent | aa7a01c558c093094ec6f3ee2ac01c4ffbc85408 (diff) | |
| parent | 808d3eff2fde7b55918f570a8a375f12116d5b1b (diff) | |
| download | mongo-014499da26d35f8c72279f3c37b3c467dfc910aa.tar.gz | |
Merge branch 'develop' into file-extend
| -rw-r--r-- | src/os_posix/os_map.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/src/os_posix/os_map.c b/src/os_posix/os_map.c index eda86c131fb..0a3cc2e4dea 100644 --- a/src/os_posix/os_map.c +++ b/src/os_posix/os_map.c @@ -36,6 +36,8 @@ __wt_mmap(WT_SESSION_IMPL *session, WT_FH *fh, void *mapp, size_t *lenp) return (0); } +#define WT_VM_PAGESIZE 4096 + /* * __wt_mmap_preload -- * Cause a section of a memory map to be faulted in. @@ -44,10 +46,10 @@ int __wt_mmap_preload(WT_SESSION_IMPL *session, void *p, size_t size) { #ifdef HAVE_POSIX_MADVISE - /* Linux requires the address be aligned to 4096 bytes */ + /* Linux requires the address be aligned to a 4KB boundary. */ WT_BM *bm = S2BT(session)->bm; WT_DECL_RET; - void *blk = (void *)((uintptr_t)p & ~(uintptr_t)4095); + void *blk = (void *)((uintptr_t)p & ~(uintptr_t)(WT_VM_PAGESIZE - 1)); size += WT_PTRDIFF(p, blk); /* XXX proxy for "am I doing a scan?" -- manual read-ahead */ @@ -60,7 +62,14 @@ __wt_mmap_preload(WT_SESSION_IMPL *session, void *p, size_t size) WT_PTRDIFF((uint8_t *)bm->map + bm->maplen, blk)); } - if ((ret = posix_madvise(blk, size, POSIX_MADV_WILLNEED)) != 0) + /* + * Manual pages aren't clear on whether alignment is required for the + * size, so we will be conservative. + */ + size &= ~(size_t)(WT_VM_PAGESIZE - 1); + + if (size > WT_VM_PAGESIZE && + (ret = posix_madvise(blk, size, POSIX_MADV_WILLNEED)) != 0) WT_RET_MSG(session, ret, "posix_madvise will need"); #else WT_UNUSED(session); @@ -79,9 +88,9 @@ int __wt_mmap_discard(WT_SESSION_IMPL *session, void *p, size_t size) { #ifdef HAVE_POSIX_MADVISE - /* Linux requires the address be aligned to 4096 bytes */ + /* Linux requires the address be aligned to a 4KB boundary. */ WT_DECL_RET; - void *blk = (void *)((uintptr_t)p & ~(uintptr_t)4095); + void *blk = (void *)((uintptr_t)p & ~(uintptr_t)(WT_VM_PAGESIZE - 1)); size += WT_PTRDIFF(p, blk); if ((ret = posix_madvise(blk, size, POSIX_MADV_DONTNEED)) != 0) |