From patchwork Wed Jul 21 12:13:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Charan Teja Kalla X-Patchwork-Id: 12390855 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 1E8ADC636C9 for ; Wed, 21 Jul 2021 13:30:35 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AC020611CE for ; Wed, 21 Jul 2021 13:30:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC020611CE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8EF186B0073; Wed, 21 Jul 2021 09:30:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8A0216B0070; Wed, 21 Jul 2021 09:30:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 654C58D0001; Wed, 21 Jul 2021 09:30:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0142.hostedemail.com [216.40.44.142]) by kanga.kvack.org (Postfix) with ESMTP id 39E6B6B0071 for ; Wed, 21 Jul 2021 09:30:33 -0400 (EDT) Received: from forelay.prod.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by fograve03.hostedemail.com (Postfix) with ESMTP id CF23418464DD8 for ; Wed, 21 Jul 2021 12:13:36 +0000 (UTC) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 7143823113 for ; Wed, 21 Jul 2021 12:13:36 +0000 (UTC) X-FDA: 78386485632.27.9600FAA Received: from so254-9.mailgun.net (so254-9.mailgun.net [198.61.254.9]) by imf13.hostedemail.com (Postfix) with ESMTP id 76EA0100BC3C for ; Wed, 21 Jul 2021 12:13:35 +0000 (UTC) DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1626869616; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=9ORgIVwVR1hRA3DPeFL9fUMvBLk6pAhPJpSd8Q2TU54=; b=WnEnDa8HItj1sYz35KFLjvKYxodyh9xE0EocA8C46I1Z6mPcjwOzdNzlnrFfFC/UgY2e7LwL U62FAqUvLQCZYhXXeO+pjXGE/7wJPLtkAsf8yyt3N1S4eXzEx+ezXUE7rnTJENl2eUJtv8Lz cQ0FTyI7npUmXX9gaW4Z/VjXLUk= X-Mailgun-Sending-Ip: 198.61.254.9 X-Mailgun-Sid: WyIwY2Q3OCIsICJsaW51eC1tbUBrdmFjay5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n02.prod.us-west-2.postgun.com with SMTP id 60f80f6ae31d882d1894d91b (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 21 Jul 2021 12:13:30 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id BFFB2C43460; Wed, 21 Jul 2021 12:13:30 +0000 (UTC) Received: from hu-charante-hyd.qualcomm.com (unknown [202.46.22.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: charante) by smtp.codeaurora.org (Postfix) with ESMTPSA id ED701C433D3; Wed, 21 Jul 2021 12:13:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org ED701C433D3 From: Charan Teja Reddy To: akpm@linux-foundation.org, vbabka@suse.cz, rientjes@google.com, nigupta@nvidia.com, khalid.aziz@oracle.com Cc: vinmenon@codeaurora.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Charan Teja Reddy Subject: [PATCH resend] mm: compaction: optimize proactive compaction deferrals Date: Wed, 21 Jul 2021 17:43:19 +0530 Message-Id: <1626869599-25412-1-git-send-email-charante@codeaurora.org> X-Mailer: git-send-email 2.7.4 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=mg.codeaurora.org header.s=smtp header.b=WnEnDa8H; spf=pass (imf13.hostedemail.com: domain of bounce@mg.codeaurora.org designates 198.61.254.9 as permitted sender) smtp.mailfrom=bounce@mg.codeaurora.org; dmarc=none X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 76EA0100BC3C X-Stat-Signature: ffm9nmuk3dk483fj1n8pt6w8rtodzt8f X-HE-Tag: 1626869615-809115 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: Vlastimil Babka figured out that when fragmentation score didn't go down across the proactive compaction i.e. when no progress is made, next wake up for proactive compaction is deferred for 1 << COMPACT_MAX_DEFER_SHIFT, i.e. 64 times, with each wakeup interval of HPAGE_FRAG_CHECK_INTERVAL_MSEC(=500). In each of this wakeup, it just decrement 'proactive_defer' counter and goes sleep i.e. it is getting woken to just decrement a counter. The same deferral time can also achieved by simply doing the HPAGE_FRAG_CHECK_INTERVAL_MSEC << COMPACT_MAX_DEFER_SHIFT thus unnecessary wakeup of kcompact thread is avoided thus also removes the need of 'proactive_defer' thread counter. Link: https://lore.kernel.org/linux-fsdevel/88abfdb6-2c13-b5a6-5b46-742d12d1c910@suse.cz/ Signed-off-by: Charan Teja Reddy Acked-by: Vlastimil Babka Reviewed-by: Khalid Aziz Acked-by: David Rientjes --- Changes in V1: o Removed the 'proactive_defer' thread counter by optimizing proactive o This is a resend as earlier it was clubbed with other changes posted at https://lore.kernel.org/patchwork/patch/1448789/ mm/compaction.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 621508e..db00dbf 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -2885,7 +2885,8 @@ static int kcompactd(void *p) { pg_data_t *pgdat = (pg_data_t *)p; struct task_struct *tsk = current; - unsigned int proactive_defer = 0; + long default_timeout = msecs_to_jiffies(HPAGE_FRAG_CHECK_INTERVAL_MSEC); + long timeout = default_timeout; const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); @@ -2902,23 +2903,30 @@ static int kcompactd(void *p) trace_mm_compaction_kcompactd_sleep(pgdat->node_id); if (wait_event_freezable_timeout(pgdat->kcompactd_wait, - kcompactd_work_requested(pgdat), - msecs_to_jiffies(HPAGE_FRAG_CHECK_INTERVAL_MSEC))) { + kcompactd_work_requested(pgdat), timeout)) { psi_memstall_enter(&pflags); kcompactd_do_work(pgdat); psi_memstall_leave(&pflags); + /* + * Reset the timeout value. The defer timeout by + * proactive compaction can effectively lost + * here but that is fine as the condition of the + * zone changed substantionally and carrying on + * with the previous defer is not useful. + */ + timeout = default_timeout; continue; } - /* kcompactd wait timeout */ + /* + * Start the proactive work with default timeout. Based + * on the fragmentation score, this timeout is updated. + */ + timeout = default_timeout; if (should_proactive_compact_node(pgdat)) { unsigned int prev_score, score; - if (proactive_defer) { - proactive_defer--; - continue; - } prev_score = fragmentation_score_node(pgdat); proactive_compact_node(pgdat); score = fragmentation_score_node(pgdat); @@ -2926,8 +2934,9 @@ static int kcompactd(void *p) * Defer proactive compaction if the fragmentation * score did not go down i.e. no progress made. */ - proactive_defer = score < prev_score ? - 0 : 1 << COMPACT_MAX_DEFER_SHIFT; + if (unlikely(score >= prev_score)) + timeout = + default_timeout << COMPACT_MAX_DEFER_SHIFT; } }