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authorJianyu Zhan <nasa4836@gmail.com>2014-06-04 16:09:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:54:07 -0700
commitbea04b073292b2acb522c7c1aa67a4fc58151530 (patch)
tree9d4efd221e0fa4b649cc6fbcfa19baa22cb3b3be /mm/vmstat.c
parente9ade569910a82614ff5f2c2cea2b65a8d785da4 (diff)
downloadlwn-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.c4
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)