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| author | Shaohua Li <shaohua.li@intel.com> | 2011-05-24 17:11:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-25 08:39:03 -0700 |
| commit | 34679d7eac9ecc20face093db9aa610f1e9c893a (patch) | |
| tree | b959da55ed4ff4f4bbd536320cb8205377a46301 /mm/mmap.c | |
| parent | 7bf02ea22c6cdd09e2d3f1d3c3fe366b834ae9af (diff) | |
| download | lwn-34679d7eac9ecc20face093db9aa610f1e9c893a.tar.gz lwn-34679d7eac9ecc20face093db9aa610f1e9c893a.zip | |
mmap: add alignment for some variables
Make some variables have correct alignment/section to avoid cache issue.
In a workload which heavily does mmap/munmap, the variables will be used
frequently.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 772140c53ab1..eaec3df82a2b 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -84,10 +84,14 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags) } EXPORT_SYMBOL(vm_get_page_prot); -int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ -int sysctl_overcommit_ratio = 50; /* default is 50% */ +int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ +int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; -struct percpu_counter vm_committed_as; +/* + * Make sure vm_committed_as in one cacheline and not cacheline shared with + * other variables. It can be updated by several CPUs frequently. + */ +struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; /* * Check that a process has enough memory to allocate a new virtual |