From patchwork Mon May 27 03:52:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Shi X-Patchwork-Id: 10962053 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C38CC933 for ; Mon, 27 May 2019 03:53:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B22E028A6A for ; Mon, 27 May 2019 03:53:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A59B528ACB; Mon, 27 May 2019 03:53:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1FC0F28A6A for ; Mon, 27 May 2019 03:53:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C7BCE6B026B; Sun, 26 May 2019 23:53:07 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id C000B6B026C; Sun, 26 May 2019 23:53:07 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AF06F6B026D; Sun, 26 May 2019 23:53:07 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) by kanga.kvack.org (Postfix) with ESMTP id 745BD6B026B for ; Sun, 26 May 2019 23:53:07 -0400 (EDT) Received: by mail-pg1-f200.google.com with SMTP id a21so3098603pgh.11 for ; Sun, 26 May 2019 20:53:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:date:message-id; bh=fTV9+QJ3Qlr+eWA8hqTAepwEMa3PO/pXGof/Ta/9BdY=; b=IsEV5a7cl/IxVQ/CJXhKOVwD5S5Ogtm2toiH5OnW3viXTmIdOQllUPiLgV8pTj1k3e rvwLMBDFfllEiTE95ItvRRDyXE9lcFzgllBjj7tOE1+AdeIfZ8aaDZ4xVm+NE2WgMG0N 8t1WEVGmjE+mZiFTUnIQkIQ4YxS3GGsrkT3S6ATn28Yw5bcr+bHAH7ggWSdryA3Owxns G0qEuvi4EMNidb0NzvwoCc3g6WfsUiQmCoS7+N+Tht79IqYprvfjeMY2beflFlnDn2fF 40Vbabi36yo2P0h89+zKeeDieJXZqIX/A4d8zMJbLM7k/dsHqoWuzSga+WdjHQpbM/vK +aOA== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.132 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com X-Gm-Message-State: APjAAAULTuwFdRvLgUgBy1Nwq+uJ0Rtr9KmlY8NypR14sV62U4BTfr6u C1a4ILr53V6uY4+MlWJkrbkPeTTxLzEIRFfHqthKOsnm51SdxE7QRjW72Xr66V72Dk3YblmDaF2 qD0Qw6KV2Qt+Ip9qmLjzZL9hI2BF41Xgs7ZYL/PbnMYrGZxSEdv+2RMIcLSuAAlCIKQ== X-Received: by 2002:a63:e54d:: with SMTP id z13mr28085705pgj.132.1558929187044; Sun, 26 May 2019 20:53:07 -0700 (PDT) X-Google-Smtp-Source: APXvYqxBHPqDYt+JLXB3HwXeML6xKfzKGf8a7Bj76qkVC5TomZAk/NGLiwDnr9fDHxDeuEm5AMRa X-Received: by 2002:a63:e54d:: with SMTP id z13mr28085649pgj.132.1558929186020; Sun, 26 May 2019 20:53:06 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1558929186; cv=none; d=google.com; s=arc-20160816; b=QcGsmJjQg0Ilq+aALK2PAjiNrNwD+gy6jFPUK24t0RejnCfDzx2vG0juplsR5IA8g0 4Do9FBN0SnS7CQ1rx4s5kBnjDyPvj1Ddm82jMblFlGQH4T0cm2Cl5M3rmqasWz00/34Y jlPGlZBzju+quQ8U06FT4GaNk6JBXKjU3hOLR08uSpdt8v9vNfMeVc8O8LFY/86cTrz8 FPsMqzVCDn+3HPK/IW6a/AEfMm1pnRXBDKGLXnN2v9/l6AvUC4IEgBDJryoYLRkfO765 /egPl/wDQJpTUmhEkupGve+PW+cwLGGK70a2XGb6NYXwCc1WIrFfJ0g6aLPsgazDPi67 Ey8Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:subject:cc:to:from; bh=fTV9+QJ3Qlr+eWA8hqTAepwEMa3PO/pXGof/Ta/9BdY=; b=J5iH6iF981K3iFree4uwO8G320C4KXC4tv3/FHL5rj2g6P8s1Epzfq2RXcvlNenIOy 5SB9leGbxZ8QHRii+ceeHKbfdQ2XEP887L9fpqMyGBctqImImDFdnSNq9v4SZNSRyz+1 F+XtkxY0ncdhkVTG1TUzvH9oJnyeK0CyVSq8sgKaV/cHvkLx7VAzA2oIIx7WYwm+CQNH +PCPN7Ovhawhyn3jhL26nPNx26e6aNNWk4+E0I2dFvS3sB/lBTZQMMbVdwERQjs0hHdz tsen3670yJlF/kYNsMK8YoMhDZhM//00jqjwjVF1KpWlMv8I72nsI8rz8MAO/NViEICZ y3mQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.132 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com. [115.124.30.132]) by mx.google.com with ESMTPS id z7si15945346pgi.365.2019.05.26.20.53.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 26 May 2019 20:53:05 -0700 (PDT) Received-SPF: pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.132 as permitted sender) client-ip=115.124.30.132; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.132 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07487;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0TSm38VC_1558929166; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TSm38VC_1558929166) by smtp.aliyun-inc.com(127.0.0.1); Mon, 27 May 2019 11:53:03 +0800 From: Yang Shi To: ying.huang@intel.com, hannes@cmpxchg.org, mhocko@suse.com, mgorman@techsingularity.net, kirill.shutemov@linux.intel.com, josef@toxicpanda.com, hughd@google.com, shakeelb@google.com, hdanton@sina.com, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [v6 PATCH 1/2] mm: vmscan: remove double slab pressure by inc'ing sc->nr_scanned Date: Mon, 27 May 2019 11:52:45 +0800 Message-Id: <1558929166-3363-1-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP The commit 9092c71bb724 ("mm: use sc->priority for slab shrink targets") has broken up the relationship between sc->nr_scanned and slab pressure. The sc->nr_scanned can't double slab pressure anymore. So, it sounds no sense to still keep sc->nr_scanned inc'ed. Actually, it would prevent from adding pressure on slab shrink since excessive sc->nr_scanned would prevent from scan->priority raise. The bonnie test doesn't show this would change the behavior of slab shrinkers. w/ w/o /sec %CP /sec %CP Sequential delete: 3960.6 94.6 3997.6 96.2 Random delete: 2518 63.8 2561.6 64.6 The slight increase of "/sec" without the patch would be caused by the slight increase of CPU usage. Cc: Josef Bacik Cc: Michal Hocko Acked-by: Johannes Weiner Signed-off-by: Yang Shi --- v4: Added Johannes's ack mm/vmscan.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 7acd0af..b65bc50 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1137,11 +1137,6 @@ static unsigned long shrink_page_list(struct list_head *page_list, if (!sc->may_unmap && page_mapped(page)) goto keep_locked; - /* Double the slab pressure for mapped and swapcache pages */ - if ((page_mapped(page) || PageSwapCache(page)) && - !(PageAnon(page) && !PageSwapBacked(page))) - sc->nr_scanned++; - may_enter_fs = (sc->gfp_mask & __GFP_FS) || (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); From patchwork Mon May 27 03:52:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Shi X-Patchwork-Id: 10962055 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BF390933 for ; 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[115.124.30.57]) by mx.google.com with ESMTPS id x32si17946705pld.190.2019.05.26.20.53.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 26 May 2019 20:53:05 -0700 (PDT) Received-SPF: pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.57 as permitted sender) client-ip=115.124.30.57; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.57 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0TSm38VC_1558929166; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TSm38VC_1558929166) by smtp.aliyun-inc.com(127.0.0.1); Mon, 27 May 2019 11:53:03 +0800 From: Yang Shi To: ying.huang@intel.com, hannes@cmpxchg.org, mhocko@suse.com, mgorman@techsingularity.net, kirill.shutemov@linux.intel.com, josef@toxicpanda.com, hughd@google.com, shakeelb@google.com, hdanton@sina.com, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [v6 PATCH 2/2] mm: vmscan: correct some vmscan counters for THP swapout Date: Mon, 27 May 2019 11:52:46 +0800 Message-Id: <1558929166-3363-2-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1558929166-3363-1-git-send-email-yang.shi@linux.alibaba.com> References: <1558929166-3363-1-git-send-email-yang.shi@linux.alibaba.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Since commit bd4c82c22c36 ("mm, THP, swap: delay splitting THP after swapped out"), THP can be swapped out in a whole. But, nr_reclaimed and some other vm counters still get inc'ed by one even though a whole THP (512 pages) gets swapped out. This doesn't make too much sense to memory reclaim. For example, direct reclaim may just need reclaim SWAP_CLUSTER_MAX pages, reclaiming one THP could fulfill it. But, if nr_reclaimed is not increased correctly, direct reclaim may just waste time to reclaim more pages, SWAP_CLUSTER_MAX * 512 pages in worst case. And, it may cause pgsteal_{kswapd|direct} is greater than pgscan_{kswapd|direct}, like the below: pgsteal_kswapd 122933 pgsteal_direct 26600225 pgscan_kswapd 174153 pgscan_direct 14678312 nr_reclaimed and nr_scanned must be fixed in parallel otherwise it would break some page reclaim logic, e.g. vmpressure: this looks at the scanned/reclaimed ratio so it won't change semantics as long as scanned & reclaimed are fixed in parallel. compaction/reclaim: compaction wants a certain number of physical pages freed up before going back to compacting. kswapd priority raising: kswapd raises priority if we scan fewer pages than the reclaim target (which itself is obviously expressed in order-0 pages). As a result, kswapd can falsely raise its aggressiveness even when it's making great progress. Other than nr_scanned and nr_reclaimed, some other counters, e.g. pgactivate, nr_skipped, nr_ref_keep and nr_unmap_fail need to be fixed too since they are user visible via cgroup, /proc/vmstat or trace points, otherwise they would be underreported. When isolating pages from LRUs, nr_taken has been accounted in base page, but nr_scanned and nr_skipped are still accounted in THP. It doesn't make too much sense too since this may cause trace point underreport the numbers as well. So accounting those counters in base page instead of accounting THP as one page. nr_dirty, nr_unqueued_dirty, nr_congested and nr_writeback are used by file cache, so they are not impacted by THP swap. This change may result in lower steal/scan ratio in some cases since THP may get split during page reclaim, then a part of tail pages get reclaimed instead of the whole 512 pages, but nr_scanned is accounted by 512, particularly for direct reclaim. But, this should be not a significant issue. Cc: "Huang, Ying" Cc: Johannes Weiner Cc: Michal Hocko Cc: Mel Gorman Cc: "Kirill A . Shutemov" Cc: Hugh Dickins Cc: Shakeel Butt Cc: Hillf Danton Signed-off-by: Yang Shi --- v6: Fixed the other double account issue introduced by v5 per Huang Ying v5: Fixed sc->nr_scanned double accounting per Huang Ying Added some comments to address the concern about premature OOM per Hillf Danton v4: Fixed the comments from Johannes and Huang Ying v3: Removed Shakeel's Reviewed-by since the patch has been changed significantly Switched back to use compound_order per Matthew Fixed more counters per Johannes v2: Added Shakeel's Reviewed-by Use hpage_nr_pages instead of compound_order per Huang Ying and William Kucharski mm/vmscan.c | 47 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 35 insertions(+), 12 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index b65bc50..378edff 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1118,6 +1118,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, int may_enter_fs; enum page_references references = PAGEREF_RECLAIM_CLEAN; bool dirty, writeback; + unsigned int nr_pages; cond_resched(); @@ -1129,7 +1130,10 @@ static unsigned long shrink_page_list(struct list_head *page_list, VM_BUG_ON_PAGE(PageActive(page), page); - sc->nr_scanned++; + nr_pages = 1 << compound_order(page); + + /* Account the number of base pages even though THP */ + sc->nr_scanned += nr_pages; if (unlikely(!page_evictable(page))) goto activate_locked; @@ -1250,7 +1254,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, case PAGEREF_ACTIVATE: goto activate_locked; case PAGEREF_KEEP: - stat->nr_ref_keep++; + stat->nr_ref_keep += nr_pages; goto keep_locked; case PAGEREF_RECLAIM: case PAGEREF_RECLAIM_CLEAN: @@ -1306,6 +1310,15 @@ static unsigned long shrink_page_list(struct list_head *page_list, } /* + * THP may get split above, need minus tail pages and update + * nr_pages to avoid accounting tail pages twice. + */ + if ((nr_pages > 1) && !PageTransHuge(page)) { + sc->nr_scanned -= (nr_pages - 1); + nr_pages = 1; + } + + /* * The page is mapped into the page tables of one or more * processes. Try to unmap it here. */ @@ -1315,7 +1328,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, if (unlikely(PageTransHuge(page))) flags |= TTU_SPLIT_HUGE_PMD; if (!try_to_unmap(page, flags)) { - stat->nr_unmap_fail++; + stat->nr_unmap_fail += nr_pages; goto activate_locked; } } @@ -1442,7 +1455,11 @@ static unsigned long shrink_page_list(struct list_head *page_list, unlock_page(page); free_it: - nr_reclaimed++; + /* + * THP may get swapped out in a whole, need account + * all base pages. + */ + nr_reclaimed += nr_pages; /* * Is there need to periodically free_page_list? It would @@ -1464,8 +1481,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, if (!PageMlocked(page)) { int type = page_is_file_cache(page); SetPageActive(page); - pgactivate++; - stat->nr_activate[type] += hpage_nr_pages(page); + stat->nr_activate[type] += nr_pages; count_memcg_page_event(page, PGACTIVATE); } keep_locked: @@ -1475,6 +1491,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page); } + pgactivate = stat->nr_activate[0] + stat->nr_activate[1]; + mem_cgroup_uncharge_list(&free_pages); try_to_unmap_flush(); free_unref_page_list(&free_pages); @@ -1646,10 +1664,9 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, LIST_HEAD(pages_skipped); isolate_mode_t mode = (sc->may_unmap ? 0 : ISOLATE_UNMAPPED); + total_scan = 0; scan = 0; - for (total_scan = 0; - scan < nr_to_scan && nr_taken < nr_to_scan && !list_empty(src); - total_scan++) { + while (scan < nr_to_scan && !list_empty(src)) { struct page *page; page = lru_to_page(src); @@ -1657,9 +1674,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, VM_BUG_ON_PAGE(!PageLRU(page), page); + nr_pages = 1 << compound_order(page); + total_scan += nr_pages; + if (page_zonenum(page) > sc->reclaim_idx) { list_move(&page->lru, &pages_skipped); - nr_skipped[page_zonenum(page)]++; + nr_skipped[page_zonenum(page)] += nr_pages; continue; } @@ -1668,11 +1688,14 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, * return with no isolated pages if the LRU mostly contains * ineligible pages. This causes the VM to not reclaim any * pages, triggering a premature OOM. + * + * Account all tail pages of THP. This would not cause + * premature OOM since __isolate_lru_page() returns -EBUSY + * only when the page is being freed somewhere else. */ - scan++; + scan += nr_pages; switch (__isolate_lru_page(page, mode)) { case 0: - nr_pages = hpage_nr_pages(page); nr_taken += nr_pages; nr_zone_taken[page_zonenum(page)] += nr_pages; list_move(&page->lru, dst);