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| author | Jianyu Zhan <nasa4836@gmail.com> | 2014-06-04 16:09:51 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-04 16:54:07 -0700 |
| commit | bea04b073292b2acb522c7c1aa67a4fc58151530 (patch) | |
| tree | 9d4efd221e0fa4b649cc6fbcfa19baa22cb3b3be /mm/vmstat.c | |
| parent | e9ade569910a82614ff5f2c2cea2b65a8d785da4 (diff) | |
| download | lwn-bea04b073292b2acb522c7c1aa67a4fc58151530.tar.gz lwn-bea04b073292b2acb522c7c1aa67a4fc58151530.zip | |
mm: use the light version __mod_zone_page_state in mlocked_vma_newpage()
mlocked_vma_newpage() is called with pte lock held(a spinlock), which
implies preemtion disabled, and the vm stat counter is not modified from
interrupt context, so we need not use an irq-safe mod_zone_page_state()
here, using a light-weight version __mod_zone_page_state() would be OK.
This patch also documents __mod_zone_page_state() and some of its
callsites. The comment above __mod_zone_page_state() is from Hugh
Dickins, and acked by Christoph.
Most credits to Hugh and Christoph for the clarification on the usage of
the __mod_zone_page_state().
[akpm@linux-foundation.org: coding-style fixes]
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index 376bd2d21482..b37bd49bfd55 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -207,7 +207,9 @@ void set_pgdat_percpu_threshold(pg_data_t *pgdat, } /* - * For use when we know that interrupts are disabled. + * For use when we know that interrupts are disabled, + * or when we know that preemption is disabled and that + * particular counter cannot be updated from interrupt context. */ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, int delta) |