Hi Chen, On Fri, Jun 06, 2014 at 04:54:26PM +0800, Chen Yucong wrote: > If (scan_balance == SCAN_FILE) is true for shrink_lruvec, then the value of > targets[LRU_INACTIVE_ANON] and targets[LRU_ACTIVE_ANON] will be zero. As a result, > the value of 'percentage' will also be zero, and the *whole* targets[LRU_INACTIVE_FILE] > and targets[LRU_ACTIVE_FILE] will be scanned. > > For (scan_balance == SCAN_ANON), there is the same conditions stated above. > > But via https://lkml.org/lkml/2013/4/10/334, we can find that the kernel does not prefer > reclaiming too many pages from the other LRU. So before recalculating the other LRU scan > count based on its original scan targets and the percentage scanning already complete, we > should need to check whether 'scan_balance' equals SCAN_FILE/SCAN_ANON. > > Signed-off-by: Chen Yucong <slaoub@xxxxxxxxx> > --- > mm/vmscan.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index d51f7e0..ca3f5f1 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2120,6 +2120,9 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) > percentage = nr_file * 100 / scan_target; > } > > + if (targets[lru] == 0 && targets[lru + LRU_ACTIVE] == 0) > + break; We have meanwhile included a change that bails out if nr_anon or nr_file are zero, right before that percentage calculation, that should cover the scenario you're describing. It's called: mm: vmscan: use proportional scanning during direct reclaim and full scan at DEF_PRIORITY -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>