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Commit 34679d7eac9ecc20face093db9aa610f1e9c893a

Authored by Shaohua Li
Committed by Linus Torvalds
1 parent 7bf02ea22c
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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>

Showing 1 changed file with 7 additions and 3 deletions Side-by-side Diff

... ... @@ -84,10 +84,14 @@
84 84 }
85 85 EXPORT_SYMBOL(vm_get_page_prot);
86 86  
87   -int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
88   -int sysctl_overcommit_ratio = 50; /* default is 50% */
  87 +int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */
  88 +int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
89 89 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
90   -struct percpu_counter vm_committed_as;
  90 +/*
  91 + * Make sure vm_committed_as in one cacheline and not cacheline shared with
  92 + * other variables. It can be updated by several CPUs frequently.
  93 + */
  94 +struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
91 95  
92 96 /*
93 97 * Check that a process has enough memory to allocate a new virtual