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| author | Hugh Dickins <hughd@google.com> | 2012-05-11 01:00:07 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-11 09:23:39 -0700 |
| commit | 1b76b02f15c70d5f392ee2e231fbd20a26063a77 (patch) | |
| tree | 5c7bee2e8a5333e9f99b64287d587a026386459e /mm | |
| parent | d60b9c16d7bae49b75255520abd7dfd2e94627bc (diff) | |
| download | lwn-1b76b02f15c70d5f392ee2e231fbd20a26063a77.tar.gz lwn-1b76b02f15c70d5f392ee2e231fbd20a26063a77.zip | |
mm: raise MemFree by reverting percpu_pagelist_fraction to 0
Why is there less MemFree than there used to be? It perturbed a test,
so I've just been bisecting linux-next, and now find the offender went
upstream yesterday.
Commit 93278814d359 "mm: fix division by 0 in percpu_pagelist_fraction()"
mistakenly initialized percpu_pagelist_fraction to the sysctl's minimum 8,
which leaves 1/8th of memory on percpu lists (on each cpu??); but most of
us expect it to be left unset at 0 (and it's not then used as a divisor).
MemTotal: 8061476kB 8061476kB 8061476kB 8061476kB 8061476kB 8061476kB
Repetitive test with percpu_pagelist_fraction 8:
MemFree: 6948420kB 6237172kB 6949696kB 6840692kB 6949048kB 6862984kB
Same test with percpu_pagelist_fraction back to 0:
MemFree: 7945000kB 7944908kB 7948568kB 7949060kB 7948796kB 7948812kB
Signed-off-by: Hugh Dickins <hughd@google.com>
[ We really should fix the crazy sysctl interface too, but that's a
separate thing - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b21b3db15a7f..918330f71dba 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -105,7 +105,7 @@ unsigned long totalreserve_pages __read_mostly; */ unsigned long dirty_balance_reserve __read_mostly; -int percpu_pagelist_fraction = 8; +int percpu_pagelist_fraction; gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; #ifdef CONFIG_PM_SLEEP |