Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752250AbbFKH7P (ORCPT ); Thu, 11 Jun 2015 03:59:15 -0400 Received: from mail113-250.mail.alibaba.com ([205.204.113.250]:36035 "EHLO us-alimail-mta1.hst.scl.en.alidc.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751920AbbFKH7G (ORCPT ); Thu, 11 Jun 2015 03:59:06 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;FP=0|-1|-1|-1|0|-1|-1|-1;HT=r41g06009;MF=hillf.zj@alibaba-inc.com;PH=DS;RN=6;RT=6;SR=0; Reply-To: "Hillf Danton" From: "Hillf Danton" To: "Mel Gorman" Cc: , "linux-kernel" , "Rik van Riel" , "Johannes Weiner" , "Michal Hocko" Subject: Re: [PATCH 04/25] mm, vmscan: Begin reclaiming pages on a per-node basis Date: Thu, 11 Jun 2015 15:58:14 +0800 Message-ID: <00fe01d0a41c$5f242bf0$1d6c83d0$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-Index: AdCkGyu4MCqNnOWPTVOb2l+hb5p6/Q== Content-Language: zh-cn Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1632 Lines: 44 > @@ -1319,6 +1322,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > struct list_head *src = &lruvec->lists[lru]; > unsigned long nr_taken = 0; > unsigned long scan; > + LIST_HEAD(pages_skipped); > > for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { > struct page *page; > @@ -1329,6 +1333,9 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > > VM_BUG_ON_PAGE(!PageLRU(page), page); > > + if (page_zone_id(page) > sc->reclaim_idx) > + list_move(&page->lru, &pages_skipped); > + > switch (__isolate_lru_page(page, mode)) { > case 0: > nr_pages = hpage_nr_pages(page); > @@ -1347,6 +1354,15 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > } > } > > + /* > + * Splice any skipped pages to the start of the LRU list. Note that > + * this disrupts the LRU order when reclaiming for lower zones but > + * we cannot splice to the tail. If we did then the SWAP_CLUSTER_MAX > + * scanning would soon rescan the same pages to skip and put the > + * system at risk of premature OOM. > + */ > + if (!list_empty(&pages_skipped)) > + list_splice(&pages_skipped, src); > *nr_scanned = scan; > trace_mm_vmscan_lru_isolate(sc->order, nr_to_scan, scan, > nr_taken, mode, is_file_lru(lru)); Can we avoid splicing pages by skipping pages with scan not incremented? Hillf -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/