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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 B9AC8C433ED for ; Mon, 3 May 2021 21:58:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3E81C611C9 for ; Mon, 3 May 2021 21:58:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E81C611C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B278D6B0036; Mon, 3 May 2021 17:58:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AD7536B006E; Mon, 3 May 2021 17:58:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9516F6B0070; Mon, 3 May 2021 17:58:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0181.hostedemail.com [216.40.44.181]) by kanga.kvack.org (Postfix) with ESMTP id 734A16B0036 for ; Mon, 3 May 2021 17:58:21 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 2D9688249980 for ; Mon, 3 May 2021 21:58:21 +0000 (UTC) X-FDA: 78101284002.03.D9725B1 Received: from mail-ed1-f49.google.com (mail-ed1-f49.google.com [209.85.208.49]) by imf22.hostedemail.com (Postfix) with ESMTP id 9931FC0007CC for ; Mon, 3 May 2021 21:58:13 +0000 (UTC) Received: by mail-ed1-f49.google.com with SMTP id e7so8108739edu.10 for ; Mon, 03 May 2021 14:58:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=LLMKm/ZQSm5fL9y/P+Fadbw94OoQzyxeONFs/WIU4Ug=; b=kyYD8cE5UO2LmEpD13MO9Bhs//1GxGUvwlPGPIMSNNPbV8vzgnoVCpb03Ns+9UOKJc P07WaocCOk4SWFIVIw16+N35lQqcDB+0+D/FPZy72/vomdP0KfoLxixVgAh/UohamQe8 HCrNJWar/bkwxyTC4cT+NGT7G37zL5FnYL+WjZK/m9jPTuo9PjGH6hxth8BFM5SDPK3j MJZI6tS/uSbOPv6wwPalfZFqDd4+qHQiBQNxSWGkQEDdKVBJ64s8+FZhxGuz2RMwOUzh +3pqNc1GDQOXkiKdOCRYLAitTmIB6t8Xsq9VXDIGG8WMKgU/rG9iakNefsfnU8iBCDJe JiGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=LLMKm/ZQSm5fL9y/P+Fadbw94OoQzyxeONFs/WIU4Ug=; b=CizKwO0ZomJJHfzGoPS9lsmtGy+gqJNhT2WmjKB/s/SFcQpwt/PtsWfbp2tuqw9m0U AmVfW9TRovDSc5hSkpT/SAZRvni5bBsAGrbSMaiX1ARU686X2Mr91+hUFiv4pTyHoRC0 sZ6+4CsBF5peAs1xItQFvNKOXYU+gxhAQ5SUnwxGEoJD8Xzhg0NcpFnXGC9XDxye5Hu2 kiTdb/bUdJmCaOsoBmMnv9wH7DnDTExlIFXmACFiVnl8W9qv49eVWy8zVOS1thnJkH5f faGC3Ora2c/gN4Ox50jNAXTN1irI/ssC4rfGsDs4XTGDnZQrNUAOq32usebAqBfp/A/C LH/Q== X-Gm-Message-State: AOAM5327CJrTwI5I6M6dTl84wepeO7TUAOKXDSgVeL8c/YFA8FBcGvo9 vDIVE/Y96UYI60UX23YhpVCASaynsEOC90vUpm4= X-Google-Smtp-Source: ABdhPJy+5zCvRdE1afqItdM+szbgQoyqG8qSWXEah2nDsB+2CYd56f2ZtI1UoT3/5WRR2zdGcykKPiiVCI6dVCXUu+o= X-Received: by 2002:aa7:cc03:: with SMTP id q3mr22960892edt.366.1620079099524; Mon, 03 May 2021 14:58:19 -0700 (PDT) MIME-Version: 1.0 References: <20210413212416.3273-1-shy828301@gmail.com> In-Reply-To: <20210413212416.3273-1-shy828301@gmail.com> From: Yang Shi Date: Mon, 3 May 2021 14:58:07 -0700 Message-ID: Subject: Re: [v2 RFC PATCH 0/7] mm: thp: use generic THP migration for NUMA hinting fault To: Mel Gorman , "Kirill A. Shutemov" , Zi Yan , Michal Hocko , Huang Ying , Hugh Dickins , Gerald Schaefer , hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, Andrew Morton Cc: Linux MM , linux-s390@vger.kernel.org, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=kyYD8cE5; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf22.hostedemail.com: domain of shy828301@gmail.com designates 209.85.208.49 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 9931FC0007CC X-Stat-Signature: q7k9mzh1a9qk4jied4jqb9ud93s6n4xx Received-SPF: none (gmail.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=mail-ed1-f49.google.com; client-ip=209.85.208.49 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620079093-681259 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: Gently ping. I also did some tests to measure the latency of do_huge_pmd_numa_page. The test VM has 80 vcpus and 64G memory. The test would create 2 processes to consume 128G memory together which would incur memory pressure to cause THP splits. And it also creates 80 processes to hog cpu, and the memory consumer processes are bound to different nodes periodically in order to increase NUMA faults. The below test script is used: echo 3 > /proc/sys/vm/drop_caches # Run stress-ng for 24 hours ./stress-ng/stress-ng --vm 2 --vm-bytes 64G --timeout 24h & PID=$! ./stress-ng/stress-ng --cpu $NR_CPUS --timeout 24h & # Wait for vm stressors forked sleep 5 PID_1=`pgrep -P $PID | awk 'NR == 1'` PID_2=`pgrep -P $PID | awk 'NR == 2'` JOB1=`pgrep -P $PID_1` JOB2=`pgrep -P $PID_2` # Bind load jobs to different nodes periodically to force generate # cross node memory access while [ -d "/proc/$PID" ] do taskset -apc 8 $JOB1 taskset -apc 8 $JOB2 sleep 300 taskset -apc 58 $JOB1 taskset -apc 58 $JOB2 sleep 300 done With the above test the histogram of latency of do_huge_pmd_numa_page is as shown below. Since the number of do_huge_pmd_numa_page varies drastically for each run (should be due to scheduler), so I converted the raw number to percentage. patched base @us[stress-ng]: [0] 3.57% 0.16% [1] 55.68% 18.36% [2, 4) 10.46% 40.44% [4, 8) 7.26% 17.82% [8, 16) 21.12% 13.41% [16, 32) 1.06% 4.27% [32, 64) 0.56% 4.07% [64, 128) 0.16% 0.35% [128, 256) < 0.1% < 0.1% [256, 512) < 0.1% < 0.1% [512, 1K) < 0.1% < 0.1% [1K, 2K) < 0.1% < 0.1% [2K, 4K) < 0.1% < 0.1% [4K, 8K) < 0.1% < 0.1% [8K, 16K) < 0.1% < 0.1% [16K, 32K) < 0.1% < 0.1% [32K, 64K) < 0.1% < 0.1% Per the result, patched kernel is even slightly better than the base kernel. I think this is because the lock contention against THP split is less than base kernel due to the refactor. To exclude the affect from THP split, I also did test w/o memory pressure. No obvious regression is spotted. The below is the test result *w/o* memory pressure. patched base @us[stress-ng]: [0] 7.97% 18.4% [1] 69.63% 58.24% [2, 4) 4.18% 2.63% [4, 8) 0.22% 0.17% [8, 16) 1.03% 0.92% [16, 32) 0.14% < 0.1% [32, 64) < 0.1% < 0.1% [64, 128) < 0.1% < 0.1% [128, 256) < 0.1% < 0.1% [256, 512) 0.45% 1.19% [512, 1K) 15.45% 17.27% [1K, 2K) < 0.1% < 0.1% [2K, 4K) < 0.1% < 0.1% [4K, 8K) < 0.1% < 0.1% [8K, 16K) 0.86% 0.88% [16K, 32K) < 0.1% 0.15% [32K, 64K) < 0.1% < 0.1% [64K, 128K) < 0.1% < 0.1% [128K, 256K) < 0.1% < 0.1% On Tue, Apr 13, 2021 at 2:24 PM Yang Shi wrote: > > > Changelog: > v1 --> v2: > * Adopted the suggestion from Gerald Schaefer to skip huge PMD for S390 > for now. > * Used PageTransHuge to distinguish base page or THP instead of a new > parameter for migrate_misplaced_page() per Huang Ying. > * Restored PMD lazily to avoid unnecessary TLB shootdown per Huang Ying. > * Skipped shared THP. > * Updated counters correctly. > * Rebased to linux-next (next-20210412). > > When the THP NUMA fault support was added THP migration was not supported yet. > So the ad hoc THP migration was implemented in NUMA fault handling. Since v4.14 > THP migration has been supported so it doesn't make too much sense to still keep > another THP migration implementation rather than using the generic migration > code. It is definitely a maintenance burden to keep two THP migration > implementation for different code paths and it is more error prone. Using the > generic THP migration implementation allows us remove the duplicate code and > some hacks needed by the old ad hoc implementation. > > A quick grep shows x86_64, PowerPC (book3s), ARM64 ans S390 support both THP > and NUMA balancing. The most of them support THP migration except for S390. > Zi Yan tried to add THP migration support for S390 before but it was not > accepted due to the design of S390 PMD. For the discussion, please see: > https://lkml.org/lkml/2018/4/27/953. > > Per the discussion with Gerald Schaefer in v1 it is acceptible to skip huge > PMD for S390 for now. > > I saw there were some hacks about gup from git history, but I didn't figure out > if they have been removed or not since I just found FOLL_NUMA code in the current > gup implementation and they seems useful. > > I'm trying to keep the behavior as consistent as possible between before and after. > But there is still some minor disparity. For example, file THP won't > get migrated at all in old implementation due to the anon_vma check, but > the new implementation doesn't need acquire anon_vma lock anymore, so > file THP might get migrated. Not sure if this behavior needs to be > kept. > > Patch #1 ~ #2 are preparation patches. > Patch #3 is the real meat. > Patch #4 ~ #6 keep consistent counters and behaviors with before. > Patch #7 skips change huge PMD to prot_none if thp migration is not supported. > > Yang Shi (7): > mm: memory: add orig_pmd to struct vm_fault > mm: memory: make numa_migrate_prep() non-static > mm: thp: refactor NUMA fault handling > mm: migrate: account THP NUMA migration counters correctly > mm: migrate: don't split THP for misplaced NUMA page > mm: migrate: check mapcount for THP instead of ref count > mm: thp: skip make PMD PROT_NONE if THP migration is not supported > > include/linux/huge_mm.h | 9 ++--- > include/linux/migrate.h | 23 ----------- > include/linux/mm.h | 3 ++ > mm/huge_memory.c | 156 +++++++++++++++++++++++++----------------------------------------------- > mm/internal.h | 21 ++-------- > mm/memory.c | 31 +++++++-------- > mm/migrate.c | 204 +++++++++++++++++++++-------------------------------------------------------------------------- > 7 files changed, 123 insertions(+), 324 deletions(-) >