From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752746AbdCAPwG (ORCPT ); Wed, 1 Mar 2017 10:52:06 -0500 Received: from mx2.suse.de ([195.135.220.15]:52565 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751664AbdCAPwA (ORCPT ); Wed, 1 Mar 2017 10:52:00 -0500 Date: Wed, 1 Mar 2017 16:51:38 +0100 From: Michal Hocko To: Johannes Weiner Cc: Andrew Morton , Jia He , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 8/9] Revert "mm, vmscan: account for skipped pages as a partial scan" Message-ID: <20170301155138.GH11730@dhcp22.suse.cz> References: <20170228214007.5621-1-hannes@cmpxchg.org> <20170228214007.5621-9-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170228214007.5621-9-hannes@cmpxchg.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 28-02-17 16:40:06, Johannes Weiner wrote: > This reverts commit d7f05528eedb047efe2288cff777676b028747b6. > > Now that reclaimability of a node is no longer based on the ratio > between pages scanned and theoretically reclaimable pages, we can > remove accounting tricks for pages skipped due to zone constraints. > > Signed-off-by: Johannes Weiner Acked-by: Michal Hocko > --- > mm/vmscan.c | 22 ++++------------------ > 1 file changed, 4 insertions(+), 18 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 35b791a8922b..ddcff8a11c1e 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1471,12 +1471,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > unsigned long nr_taken = 0; > unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 }; > unsigned long nr_skipped[MAX_NR_ZONES] = { 0, }; > - unsigned long skipped = 0, total_skipped = 0; > + unsigned long skipped = 0; > unsigned long scan, nr_pages; > LIST_HEAD(pages_skipped); > > for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan && > - !list_empty(src);) { > + !list_empty(src); scan++) { > struct page *page; > > page = lru_to_page(src); > @@ -1490,12 +1490,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > continue; > } > > - /* > - * Account for scanned and skipped separetly to avoid the pgdat > - * being prematurely marked unreclaimable by pgdat_reclaimable. > - */ > - scan++; > - > switch (__isolate_lru_page(page, mode)) { > case 0: > nr_pages = hpage_nr_pages(page); > @@ -1524,6 +1518,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > if (!list_empty(&pages_skipped)) { > int zid; > > + list_splice(&pages_skipped, src); > for (zid = 0; zid < MAX_NR_ZONES; zid++) { > if (!nr_skipped[zid]) > continue; > @@ -1531,17 +1526,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]); > skipped += nr_skipped[zid]; > } > - > - /* > - * Account skipped pages as a partial scan as the pgdat may be > - * close to unreclaimable. If the LRU list is empty, account > - * skipped pages as a full scan. > - */ > - total_skipped = list_empty(src) ? skipped : skipped >> 2; > - > - list_splice(&pages_skipped, src); > } > - *nr_scanned = scan + total_skipped; > + *nr_scanned = scan; > trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, > scan, skipped, nr_taken, mode, lru); > update_lru_sizes(lruvec, lru, nr_zone_taken); > -- > 2.11.1 -- Michal Hocko SUSE Labs