Hi Shaohua, On Thu, Feb 23, 2017 at 10:15:50PM -0800, Shaohua Li wrote: > On Fri, Feb 24, 2017 at 10:49:39AM +0900, Minchan Kim wrote: > > On Wed, Feb 22, 2017 at 10:50:41AM -0800, Shaohua Li wrote: > > > madv MADV_FREE indicate pages are 'lazyfree'. They are still anonymous > > > pages, but they can be freed without pageout. To destinguish them > > > against normal anonymous pages, we clear their SwapBacked flag. > > > > > > MADV_FREE pages could be freed without pageout, so they pretty much like > > > used once file pages. For such pages, we'd like to reclaim them once > > > there is memory pressure. Also it might be unfair reclaiming MADV_FREE > > > pages always before used once file pages and we definitively want to > > > reclaim the pages before other anonymous and file pages. > > > > > > To speed up MADV_FREE pages reclaim, we put the pages into > > > LRU_INACTIVE_FILE list. The rationale is LRU_INACTIVE_FILE list is tiny > > > nowadays and should be full of used once file pages. Reclaiming > > > MADV_FREE pages will not have much interfere of anonymous and active > > > file pages. And the inactive file pages and MADV_FREE pages will be > > > reclaimed according to their age, so we don't reclaim too many MADV_FREE > > > pages too. Putting the MADV_FREE pages into LRU_INACTIVE_FILE_LIST also > > > means we can reclaim the pages without swap support. This idea is > > > suggested by Johannes. > > > > > > This patch doesn't move MADV_FREE pages to LRU_INACTIVE_FILE list yet to > > > avoid bisect failure, next patch will do it. > > > > > > The patch is based on Minchan's original patch. > > > > > > Cc: Michal Hocko <mho...@suse.com> > > > Cc: Minchan Kim <minc...@kernel.org> > > > Cc: Hugh Dickins <hu...@google.com> > > > Cc: Rik van Riel <r...@redhat.com> > > > Cc: Mel Gorman <mgor...@techsingularity.net> > > > Cc: Andrew Morton <a...@linux-foundation.org> > > > Suggested-by: Johannes Weiner <han...@cmpxchg.org> > > > Signed-off-by: Shaohua Li <s...@fb.com> > > > > Other than that Johannes pointed out, code itself looks good to me. > > However, I hope to merge this patch with next one. > > It's enough simple to merge, change behavior(about deactivation), > > mark_page_lazyfree is introduced but there is no callsite to use it > > in this patch. > > > > I don't think it's worth to separate. > > I think it's more clear in this way, doing one thing in one patch.
There are several times to prevent it that introduce new function *here* and use it *there*. One of example from Johannes: https://marc.info/?l=linux-mm&m=147430500910960&w=2 I don't understand why this case is okay. Nomally, it's anti-pattern for git-bisect which adds uselss bisect point. Even, if it were good for review, I might agree but this case is not that, too.
