From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAA04C10F13 for ; Thu, 11 Apr 2019 03:58:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A00B62133D for ; Thu, 11 Apr 2019 03:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727059AbfDKD60 (ORCPT ); Wed, 10 Apr 2019 23:58:26 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:33578 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726595AbfDKD6Z (ORCPT ); Wed, 10 Apr 2019 23:58:25 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R861e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07486;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=15;SR=0;TI=SMTPD_---0TP0I5rB_1554955031; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TP0I5rB_1554955031) by smtp.aliyun-inc.com(127.0.0.1); Thu, 11 Apr 2019 11:57:23 +0800 From: Yang Shi To: mhocko@suse.com, mgorman@techsingularity.net, riel@surriel.com, hannes@cmpxchg.org, akpm@linux-foundation.org, dave.hansen@intel.com, keith.busch@intel.com, dan.j.williams@intel.com, fengguang.wu@intel.com, fan.du@intel.com, ying.huang@intel.com, ziy@nvidia.com Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [v2 PATCH 7/9] mm: vmscan: check if the demote target node is contended or not Date: Thu, 11 Apr 2019 11:56:57 +0800 Message-Id: <1554955019-29472-8-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1554955019-29472-1-git-send-email-yang.shi@linux.alibaba.com> References: <1554955019-29472-1-git-send-email-yang.shi@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When demoting to PMEM node, the target node may have memory pressure, then the memory pressure may cause migrate_pages() fail. If the failure is caused by memory pressure (i.e. returning -ENOMEM), tag the node with PGDAT_CONTENDED. The tag would be cleared once the target node is balanced again. Check if the target node is PGDAT_CONTENDED or not, if it is just skip demotion. Signed-off-by: Yang Shi --- include/linux/mmzone.h | 3 +++ mm/vmscan.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index fba7741..de534db 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -520,6 +520,9 @@ enum pgdat_flags { * many pages under writeback */ PGDAT_RECLAIM_LOCKED, /* prevents concurrent reclaim */ + PGDAT_CONTENDED, /* the node has not enough free memory + * available + */ }; enum zone_flags { diff --git a/mm/vmscan.c b/mm/vmscan.c index 80cd624..50cde53 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1048,6 +1048,9 @@ static void page_check_dirty_writeback(struct page *page, static inline bool is_demote_ok(int nid, struct scan_control *sc) { + int node; + nodemask_t used_mask; + /* It is pointless to do demotion in memcg reclaim */ if (!global_reclaim(sc)) return false; @@ -1060,6 +1063,13 @@ static inline bool is_demote_ok(int nid, struct scan_control *sc) if (!has_cpuless_node_online()) return false; + /* Check if the demote target node is contended or not */ + nodes_clear(used_mask); + node = find_next_best_node(nid, &used_mask, true); + + if (test_bit(PGDAT_CONTENDED, &NODE_DATA(node)->flags)) + return false; + return true; } @@ -1502,6 +1512,10 @@ static unsigned long shrink_page_list(struct list_head *page_list, nr_reclaimed += nr_succeeded; if (err) { + if (err == -ENOMEM) + set_bit(PGDAT_CONTENDED, + &NODE_DATA(target_nid)->flags); + putback_movable_pages(&demote_pages); list_splice(&ret_pages, &demote_pages); @@ -2596,6 +2610,19 @@ static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memc * scan target and the percentage scanning already complete */ lru = (lru == LRU_FILE) ? LRU_BASE : LRU_FILE; + + /* + * The shrink_page_list() may find the demote target node is + * contended, if so it doesn't make sense to scan anonymous + * LRU again. + * + * Need check if swap is available or not too since demotion + * may happen on swapless system. + */ + if (!is_demote_ok(pgdat->node_id, sc) && + (!sc->may_swap || mem_cgroup_get_nr_swap_pages(memcg) <= 0)) + lru = LRU_FILE; + nr_scanned = targets[lru] - nr[lru]; nr[lru] = targets[lru] * (100 - percentage) / 100; nr[lru] -= min(nr[lru], nr_scanned); @@ -3458,6 +3485,7 @@ static void clear_pgdat_congested(pg_data_t *pgdat) clear_bit(PGDAT_CONGESTED, &pgdat->flags); clear_bit(PGDAT_DIRTY, &pgdat->flags); clear_bit(PGDAT_WRITEBACK, &pgdat->flags); + clear_bit(PGDAT_CONTENDED, &pgdat->flags); } /* -- 1.8.3.1