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author | Andi Kleen <ak@linux.intel.com> | 2011-05-24 17:12:29 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-25 08:39:26 -0700 |
commit | 207d04baa3591a354711e863dd90087fc75873b3 (patch) | |
tree | 17498d55af5b2a588e7e7111e927a099236ca770 /scripts/unifdef.c | |
parent | 275b12bf5486f6f531111fd3d7dbbf01df427cfe (diff) | |
download | kernel_samsung_crespo-207d04baa3591a354711e863dd90087fc75873b3.zip kernel_samsung_crespo-207d04baa3591a354711e863dd90087fc75873b3.tar.gz kernel_samsung_crespo-207d04baa3591a354711e863dd90087fc75873b3.tar.bz2 |
readahead: reduce unnecessary mmap_miss increases
The original INT_MAX is too large, reduce it to
- avoid unnecessarily dirtying/bouncing the cache line
- restore mmap read-around faster on changed access pattern
Background: in the mosbench exim benchmark which does multi-threaded page
faults on shared struct file, the ra->mmap_miss updates are found to cause
excessive cache line bouncing on tmpfs. The ra state updates are needless
for tmpfs because it actually disabled readahead totally
(shmem_backing_dev_info.ra_pages == 0).
Tested-by: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'scripts/unifdef.c')
0 files changed, 0 insertions, 0 deletions