Messages in this thread Patch in this message | | | Date | Wed, 15 Dec 2010 11:01:27 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [cpuops cmpxchg V2 4/5] vmstat: User per cpu atomics to avoid interrupt disable / enable |
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On Wed, 15 Dec 2010, Tejun Heo wrote:
> + /* > + * The fetching of the stat_threshold is racy. We may apply > + * a counter threshold to the wrong the cpu if we get > + * rescheduled while executing here. However, the following > + * will apply the threshold again and therefore bring the > + * counter under the threshold. > + */ > > What does "the following" mean here? Later executions of the > function? It seems like the counter can go out of the threshold at > least temporarily, which probably is okay but I think the comment can > be improved a bit.
I meant later execution of the function. I will fix the comment.
Subject: vmstat comment fix
Clarify comments for the threshold a bit.
Signed-off-by: Christoh Lameter <cl@linux.com>
--- mm/vmstat.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
Index: linux-2.6/mm/vmstat.c =================================================================== --- linux-2.6.orig/mm/vmstat.c 2010-12-15 10:57:44.000000000 -0600 +++ linux-2.6/mm/vmstat.c 2010-12-15 10:58:46.000000000 -0600 @@ -277,9 +277,12 @@ static inline void mod_state(struct zone /* * The fetching of the stat_threshold is racy. We may apply * a counter threshold to the wrong the cpu if we get - * rescheduled while executing here. However, the following - * will apply the threshold again and therefore bring the - * counter under the threshold. + * rescheduled while executing here. However, the next + * counter update will apply the threshold again and + * therefore bring the counter under the threshold again. + * + * Most of the time the thresholds are the same anyways + * for all cpus in a zone. */ t = this_cpu_read(pcp->stat_threshold);
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