Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751610AbdCCDwz (ORCPT ); Thu, 2 Mar 2017 22:52:55 -0500 Received: from LGEAMRELO12.lge.com ([156.147.23.52]:54119 "EHLO lgeamrelo12.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751478AbdCCDww (ORCPT ); Thu, 2 Mar 2017 22:52:52 -0500 X-Original-SENDERIP: 156.147.1.127 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 165.244.249.26 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.223.161 X-Original-MAILFROM: minchan@kernel.org Date: Fri, 3 Mar 2017 11:52:37 +0900 From: Minchan Kim To: CC: , , , , , , , Subject: Re: + mm-reclaim-madv_free-pages.patch added to -mm tree Message-ID: <20170303025237.GB3503@bbox> References: <58b616a6.hCl1D/BVn0fPDi+K%akpm@linux-foundation.org> MIME-Version: 1.0 In-Reply-To: <58b616a6.hCl1D/BVn0fPDi+K%akpm@linux-foundation.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB04/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/03/03 11:52:37, Serialize by Router on LGEKRMHUB04/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/03/03 11:52:37, Serialize complete at 2017/03/03 11:52:37 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4696 Lines: 136 Hi, On Tue, Feb 28, 2017 at 04:32:38PM -0800, akpm@linux-foundation.org wrote: > > The patch titled > Subject: mm: reclaim MADV_FREE pages > has been added to the -mm tree. Its filename is > mm-reclaim-madv_free-pages.patch > > This patch should soon appear at > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch > and later at > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/SubmitChecklist when testing your code *** > > The -mm tree is included into linux-next and is updated > there every 3-4 working days > > ------------------------------------------------------ > From: Shaohua Li > Subject: mm: reclaim MADV_FREE pages > > When memory pressure is high, we free MADV_FREE pages. If the pages are > not dirty in pte, the pages could be freed immediately. Otherwise we > can't reclaim them. We put the pages back to anonumous LRU list (by > setting SwapBacked flag) and the pages will be reclaimed in normal swapout > way. > > We use normal page reclaim policy. Since MADV_FREE pages are put into > inactive file list, such pages and inactive file pages are reclaimed > according to their age. This is expected, because we don't want to > reclaim too many MADV_FREE pages before used once pages. > > Based on Minchan's original patch > > Link: http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.shli@fb.com > Signed-off-by: Shaohua Li > Acked-by: Minchan Kim > Acked-by: Michal Hocko > Acked-by: Johannes Weiner > Acked-by: Hillf Danton > Cc: Hugh Dickins > Cc: Rik van Riel > Cc: Mel Gorman > Signed-off-by: Andrew Morton > --- < snip > > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page > VM_BUG_ON_PAGE(!PageSwapCache(page) && PageSwapBacked(page), > page); > > - if (!PageDirty(page)) { > + /* > + * swapin page could be clean, it has data stored in > + * swap. We can't silently discard it without setting > + * swap entry in the page table. > + */ > + if (!PageDirty(page) && !PageSwapCache(page)) { > /* It's a freeable page by MADV_FREE */ > dec_mm_counter(mm, MM_ANONPAGES); > - rp->lazyfreed++; > goto discard; > + } else if (!PageSwapBacked(page)) { > + /* dirty MADV_FREE page */ > + set_pte_at(mm, address, pvmw.pte, pteval); > + ret = SWAP_DIRTY; > + page_vma_mapped_walk_done(&pvmw); > + break; > } There is no point to make this logic complicated with clean swapin-page. Andrew, Could you fold below patch into the mm-reclaim-madv_free-pages.patch if others are not against? Thanks. >From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Fri, 3 Mar 2017 11:42:52 +0900 Subject: [PATCH] mm: clean up lazyfree page handling We can make it simple to understand without need to be aware of clean-swapin page. This patch just clean up lazyfree page handling in try_to_unmap_one. Signed-off-by: Minchan Kim --- mm/rmap.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index bb45712..f7eab40 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, VM_BUG_ON_PAGE(!PageSwapCache(page) && PageSwapBacked(page), page); - /* - * swapin page could be clean, it has data stored in - * swap. We can't silently discard it without setting - * swap entry in the page table. - */ - if (!PageDirty(page) && !PageSwapCache(page)) { - /* It's a freeable page by MADV_FREE */ - dec_mm_counter(mm, MM_ANONPAGES); - goto discard; - } else if (!PageSwapBacked(page)) { - /* dirty MADV_FREE page */ + /* MADV_FREE page check */ + if (!PageSwapBacked(page)) { + if (!PageDirty(page)) { + dec_mm_counter(mm, MM_ANONPAGES); + goto discard; + } + + /* + * If the page was redirtied, it cannot be + * discarded. Remap the page to page table. + */ set_pte_at(mm, address, pvmw.pte, pteval); ret = SWAP_DIRTY; page_vma_mapped_walk_done(&pvmw); -- 2.7.4