From patchwork Sat May 25 03:28:32 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Shi X-Patchwork-Id: 10960641 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 278B413AD for ; Sat, 25 May 2019 03:28:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0A46B28A5D for ; Sat, 25 May 2019 03:28:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F06B028A60; Sat, 25 May 2019 03:28:50 +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 3AD2328A5D for ; Sat, 25 May 2019 03:28:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1BEB56B0010; Fri, 24 May 2019 23:28:48 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 16FB96B0266; Fri, 24 May 2019 23:28:48 -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 036976B0269; Fri, 24 May 2019 23:28:47 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) by kanga.kvack.org (Postfix) with ESMTP id C045D6B0010 for ; Fri, 24 May 2019 23:28:47 -0400 (EDT) Received: by mail-pg1-f198.google.com with SMTP id e16so7589130pga.4 for ; Fri, 24 May 2019 20:28:47 -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=SJMAsOBcF9RoTOIf8WiSglzrsOnSpDGYYF+YBn4yBoGGE4RA1blbkEYv9u0dcq1weG Lafob1f8Xlxzy00fcNDX3QbNi2OXvBy3Rq3ZGpjjogvqwKjlcD9lk7e/KrAh5ljRbJxl 6/40z3SgezBRtv97Nrsi693uoAt5onHbK7BOop5exFh5fcP1WhHPMyeFbI7WBz+MzC75 bp0qw9h+QCy+MsXv/cBtFkSCNZNH+IUZCDpIaWVeslNtO9z/hTDsUSL4f8bqXU1gDtih GNgXoVDIs5C9ubVzCRNVfhgN5QglWIjfBuKtbRSu02cxMO2a6mlMITwhXIGLJwZSflY2 kTWQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.43 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: APjAAAWpxKgwgrjh/7bhwcinIHmB1THj5Z7BgQHoewQQqnoJr9cgvgEG ot7nClcWU6i56l05A1QFqaBuhJPK7/fPIyMwJjQdxk2RezwXd3S1i1vvtxFDlnyoO830NPtW/ai fsQDkIvwLCue0CgP9h74PStbfEKbhNqE8NAmZteUAbLcO/fw4a5DpZuEym3LfPaM3KA== X-Received: by 2002:a17:902:6ac8:: with SMTP id i8mr42545812plt.27.1558754927239; Fri, 24 May 2019 20:28:47 -0700 (PDT) X-Google-Smtp-Source: APXvYqzPcW8xCv2aUs2T2vePvm6ZT7b/L5sbcze27fx8Zx4gNFaTsEPHqlE9cDet5gjG2vNoq+or X-Received: by 2002:a17:902:6ac8:: with SMTP id i8mr42545745plt.27.1558754925824; Fri, 24 May 2019 20:28:45 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1558754925; cv=none; d=google.com; s=arc-20160816; b=VFcOlwTusMK4gTaSmJ6oHBuiHDv5/a080tBo9+He10LS5M1SPBJaCMSeEPNNbZjoW+ Wt9utQGXBLIcVti5OjTpXolggsV0kYdEonf2r1k+xKz4VgYTI89hj9dbzwzuJiiokhOM IZ1Ewq6lCEHZhdqrBjJfN5k0LoCndQdZYpajAtS0va+wwBZEvk5V2er5uxa3ZZJID/LF lFd8k6gUreHXsCKOeFUPWxdhG0tbtIyG+BEOyhSp38t9jOze18Uk7j5jZocGeXKmvQ6S Onj9yshYN+RCWgrY/o/EFDgGm1RE5x4FLtmwiqQNBq8rMh/d5HrSdpfLx4+bHc1i3uiV toHQ== 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=HOUMc4Qs0fVXhSIn9HIEQ+eiCGu/i66UrMqLAnImOAvDF1ZFkkRHdbPpI6V78AVn7i +ME3Ubwc1sXTJt/kDuKnOp8rWf+qykdKmp91eGpsdMJEktO3MjJy+YZH99IbBzrWGs4F Xz1VPCW892WVDDjN9ARCFZ8yVg2W05qWze0XQeui+e/dXUgwc1VqY1stgi56AgYls2Tu oVglCQaWR/6Ts2kwQVdX+LpsFBTj7/Oqw3SqtfcGON4hOaMIg09c5e0Rsvko1l71ycJU XUCU7z5Xuf+yC4L+WrxqxMR0hi4nhJbhxWAHBOnc5ScU69RnoB/j2WBm+zOoI3S7g1Ar yNgA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.43 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com. [115.124.30.43]) by mx.google.com with ESMTPS id h3si6434249pjb.19.2019.05.24.20.28.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 May 2019 20:28:45 -0700 (PDT) Received-SPF: pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.43 as permitted sender) client-ip=115.124.30.43; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.43 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=12;SR=0;TI=SMTPD_---0TScWUY1_1558754913; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TScWUY1_1558754913) by smtp.aliyun-inc.com(127.0.0.1); Sat, 25 May 2019 11:28:42 +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, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [v5 PATCH 1/2] mm: vmscan: remove double slab pressure by inc'ing sc->nr_scanned Date: Sat, 25 May 2019 11:28:32 +0800 Message-Id: <1558754913-96989-1-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 Sat May 25 03:28:33 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Shi X-Patchwork-Id: 10960643 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 891A1912 for ; 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[115.124.30.132]) by mx.google.com with ESMTPS id v6si2924712ion.63.2019.05.24.20.29.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 May 2019 20:29:01 -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=01201311R371e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0TScWUY1_1558754913; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TScWUY1_1558754913) by smtp.aliyun-inc.com(127.0.0.1); Sat, 25 May 2019 11:28:42 +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, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [v5 PATCH 2/2] mm: vmscan: correct some vmscan counters for THP swapout Date: Sat, 25 May 2019 11:28:33 +0800 Message-Id: <1558754913-96989-2-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1558754913-96989-1-git-send-email-yang.shi@linux.alibaba.com> References: <1558754913-96989-1-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 Signed-off-by: Yang Shi --- 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 | 42 +++++++++++++++++++++++++++++++----------- 1 file changed, 31 insertions(+), 11 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index b65bc50..f4f4d57 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(); @@ -1129,6 +1130,13 @@ static unsigned long shrink_page_list(struct list_head *page_list, VM_BUG_ON_PAGE(PageActive(page), page); + nr_pages = 1 << compound_order(page); + + /* + * Accounted one page for THP for now. If THP gets swapped + * out in a whole, will account all tail pages later to + * avoid accounting tail pages twice. + */ sc->nr_scanned++; if (unlikely(!page_evictable(page))) @@ -1250,7 +1258,7 @@ 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: @@ -1292,7 +1300,9 @@ static unsigned long shrink_page_list(struct list_head *page_list, #endif if (!add_to_swap(page)) goto activate_locked; - } + } else + /* Account tail pages for THP */ + sc->nr_scanned += nr_pages - 1; may_enter_fs = 1; @@ -1315,7 +1325,7 @@ 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 +1452,11 @@ 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 += (1 << compound_order(page)); /* * Is there need to periodically free_page_list? It would @@ -1464,7 +1478,6 @@ 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); count_memcg_page_event(page, PGACTIVATE); } @@ -1475,6 +1488,8 @@ 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 +1661,9 @@ 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 +1671,12 @@ 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 +1685,14 @@ 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);