On Mon, Apr 9, 2012 at 12:50 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, 9 Apr 2012 12:42:04 -0700 > Ying Han <yinghan@xxxxxxxxxx> wrote: > >> This reverts commit c38446cc65e1f2b3eb8630c53943b94c4f65f670. >> >> Before the commit, the code makes senses to me but not after the commit. The >> "nr_reclaimed" is the number of pages reclaimed by scanning through the memcg's >> lru lists. The "nr_to_reclaim" is the target value for the whole function. For >> example, we like to early break the reclaim if reclaimed 32 pages under direct >> reclaim (not DEF_PRIORITY). >> >> After the reverted commit, the target "nr_to_reclaim" is decremented each time >> by "nr_reclaimed" but we still use it to compare the "nr_reclaimed". It just >> doesn't make sense to me... >> >> Signed-off-by: Ying Han <yinghan@xxxxxxxxxx> >> --- >> mm/vmscan.c | 7 +------ >> 1 files changed, 1 insertions(+), 6 deletions(-) >> >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index 33c332b..1a51868 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -2107,12 +2107,7 @@ restart: >> * with multiple processes reclaiming pages, the total >> * freeing target can get unreasonably large. >> */ >> - if (nr_reclaimed >= nr_to_reclaim) >> - nr_to_reclaim = 0; >> - else >> - nr_to_reclaim -= nr_reclaimed; >> - >> - if (!nr_to_reclaim && priority < DEF_PRIORITY) >> + if (nr_reclaimed >= nr_to_reclaim && priority < DEF_PRIORITY) >> break; >> } >> blk_finish_plug(&plug); > > This code is all within a loop: the "goto restart" thing. We reset > nr_reclaimed to zero each time around that loop. nr_to_reclaim is (or > rather, was) constant throughout the entire function. > > Comparing nr_reclaimed (whcih is reset each time around the loop) to > nr_to_reclaim made no sense. > > I think the code as it stands is ugly. It would be better to make > nr_to_reclaim a const and to add another local total_reclaimed, and > compare that with nr_to_reclaim. Ok, I will resend the patch w/ the "total_reclaimed" change. --Ying Or just stop resetting nr_reclaimed > each time around the loop. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href