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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F52CC433EF for ; Tue, 26 Apr 2022 11:06:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 642386B0073; Tue, 26 Apr 2022 07:06:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5F2056B0074; Tue, 26 Apr 2022 07:06:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 492176B0075; Tue, 26 Apr 2022 07:06:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id 3939E6B0073 for ; Tue, 26 Apr 2022 07:06:18 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 0485460D4C for ; Tue, 26 Apr 2022 11:06:17 +0000 (UTC) X-FDA: 79398751194.13.BD4E337 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf09.hostedemail.com (Postfix) with ESMTP id F1B84140043 for ; Tue, 26 Apr 2022 11:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650971176; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DHfnXNbbraU+74d3T1xSt5cZBiLAUCkRDpQuxcIh3qo=; b=OtZQ5ozPgzFjZ586LYoKznp5B4cTc7ysE0wtVOIqzo0hg25xq6tcRWMzUeT0hCAnuybaTs KiJP9RtQJmTUv+MxNuJAbOXv8ezvAglZ+LAd4Xj3yrRtmrWmhJm3niS0jttZiG968tK7dV 4DOhPR+0dg34uooBEBfBOTBLjS/CBx0= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-528-pua-ocPUMrSN5tE7pvZC-Q-1; Tue, 26 Apr 2022 07:06:15 -0400 X-MC-Unique: pua-ocPUMrSN5tE7pvZC-Q-1 Received: by mail-wm1-f71.google.com with SMTP id r186-20020a1c44c3000000b00393f52ed5ceso303349wma.7 for ; Tue, 26 Apr 2022 04:06:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=DHfnXNbbraU+74d3T1xSt5cZBiLAUCkRDpQuxcIh3qo=; b=TbXr9o+KjsFTqukRMvyO53gyvxaoItIAdquE8Y28EiFhUzRXGM4N6CsdB9l13f4uz2 +2RH2OFoJ7yzNjCMJospNPilHs+xNbo61shkYCTW0uQc6Qph1kUcR6Nb7qSRJoBANPpx GNjyyMR79Y1rnPYf3yp3tc8a8lZtjIdoDqXOJbX0lxQ58wPJ7LsfQcLbC1vlE12T65+1 co78eI6xUN9uZZRKhPPgp/heS6rcBI+5UlOKd6jF0RJISg7p2MiK4oLQNwFQYRUA9DhA aRsgu7W8WJOgkUuoYolnP85TWTfqmdWnpPL61mc7696rAbkAPzsJvWtx/0dhHGJ6YC+N b5Jw== X-Gm-Message-State: AOAM531p50pAcmpIRUf1xfer3hVc3SnosoWf4LmUphWldBDkT1BT7MSe 07B7K8rCDx7pEYEw2zaWDHoC9+NUayDvb+eZOj4M/bQVDgVJH4YAHCb+HrDT4DDKLywaqkegUmq UrM8AsLO1aqk= X-Received: by 2002:a05:6000:223:b0:20a:db3a:e761 with SMTP id l3-20020a056000022300b0020adb3ae761mr7883435wrz.43.1650971173746; Tue, 26 Apr 2022 04:06:13 -0700 (PDT) X-Google-Smtp-Source: ABdhPJy+Ob9PQFNXcWbkfeMMvapipW9rElBZyeHIS9L5GSq7xdZt6/Me6QPwGd36G3ygXGirhLZhSw== X-Received: by 2002:a05:6000:223:b0:20a:db3a:e761 with SMTP id l3-20020a056000022300b0020adb3ae761mr7883418wrz.43.1650971173519; Tue, 26 Apr 2022 04:06:13 -0700 (PDT) Received: from ?IPv6:2a0c:5a80:1306:2f00:cfcf:62cf:6f38:dd92? ([2a0c:5a80:1306:2f00:cfcf:62cf:6f38:dd92]) by smtp.gmail.com with ESMTPSA id r17-20020a0560001b9100b00207afaa8987sm12848160wru.27.2022.04.26.04.06.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Apr 2022 04:06:13 -0700 (PDT) Message-ID: Subject: Re: [RFC PATCH 0/6] Drain remote per-cpu directly From: Nicolas Saenz Julienne To: Minchan Kim , Mel Gorman Cc: Marcelo Tosatti , Vlastimil Babka , Michal Hocko , LKML , Linux-MM Date: Tue, 26 Apr 2022 13:06:12 +0200 In-Reply-To: References: <20220420095906.27349-1-mgorman@techsingularity.net> User-Agent: Evolution 3.42.4 (3.42.4-2.fc35) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=OtZQ5ozP; spf=none (imf09.hostedemail.com: domain of nsaenzju@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=nsaenzju@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: F1B84140043 X-Stat-Signature: zabqokzgx8xyaoa1tw451e7eu9hixo5t X-HE-Tag: 1650971173-547192 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: On Mon, 2022-04-25 at 15:58 -0700, Minchan Kim wrote: > On Wed, Apr 20, 2022 at 10:59:00AM +0100, Mel Gorman wrote: > > This series has the same intent as Nicolas' series "mm/page_alloc: Remote > > per-cpu lists drain support" -- avoid interference of a high priority > > task due to a workqueue item draining per-cpu page lists. While many > > workloads can tolerate a brief interruption, it may be cause a real-time > > task runnning on a NOHZ_FULL CPU to miss a deadline and at minimum, > > the draining in non-deterministic. > > Yeah, the non-deterministic is a problem. I saw the kworker-based draining > takes 100+ms(up to 300ms observed) sometimes in alloc_contig_range if CPUs > are heavily loaded. > > I am not sure Nicolas already observed. it's not only problem of > per_cpu_pages but it is also lru_pvecs (pagevec) draining. > Do we need to introduce similar(allow remote drainning with spin_lock) > solution for pagevec? Yes, I'm aware of the lru problem. I'll start working on it too once we're done with the page allocator (and if no-one beats me to it). That said, I don't know if we can apply the exact same approach, the devil is in the details. :) -- Nicolás Sáenz