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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 EA5DBC48BDF for ; Fri, 18 Jun 2021 15:22:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BCB2260FEE for ; Fri, 18 Jun 2021 15:22:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233961AbhFRPYY (ORCPT ); Fri, 18 Jun 2021 11:24:24 -0400 Received: from so254-9.mailgun.net ([198.61.254.9]:44960 "EHLO so254-9.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235089AbhFRPWZ (ORCPT ); Fri, 18 Jun 2021 11:22:25 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1624029615; h=References: In-Reply-To: References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=GbdhK0pYr+SV7ujRBPEtOv5KYsxMwa7KTk/9Vpru6QA=; b=Pyk/iERTnfbAlUIera/laRMFxVMZZ8v1WsoYOhk1jejNImuku+e1GVzqUiIQNPwL3n2ux1fp jSsLwmax0o4t9PVQx/0A4d1iPUsmYxIrTzTjPOdioE9FKzeIQN//RcIyN0hE7EM5cGpwtple dWmIsljyiZp2Y0bMlBz6IYIyRGc= X-Mailgun-Sending-Ip: 198.61.254.9 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n07.prod.us-west-2.postgun.com with SMTP id 60ccb994b6ccaab7539a15e5 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 18 Jun 2021 15:19:48 GMT Sender: charante=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id E9F05C4360C; Fri, 18 Jun 2021 15:19:47 +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 838EFC43144; Fri, 18 Jun 2021 15:19:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 838EFC43144 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=charante@codeaurora.org From: Charan Teja Reddy To: akpm@linux-foundation.org, vbabka@suse.cz, corbet@lwn.net, mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com, osalvador@suse.de, rientjes@google.com, mchehab+huawei@kernel.org, lokeshgidra@google.com, andrew.a.klychkov@gmail.com, xi.fengfei@h3c.com, nigupta@nvidia.com, dave.hansen@linux.intel.com, famzheng@amazon.com, mateusznosek0@gmail.com, oleksandr@redhat.com, sh_def@163.com Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Charan Teja Reddy Subject: [PATCH V4 1/3] mm: compaction: optimize proactive compaction deferrals Date: Fri, 18 Jun 2021 20:48:53 +0530 Message-Id: X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(=6) 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. Suggested-by: Vlastimil Babka Signed-off-by: Charan Teja Reddy --- Changes in V4: -- Removed the 'proactive_defer' thread counter by optimizing proactive compaction deferrals. -- Changes from V1 through V3 doesn't exist. mm/compaction.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 84fde27..bfbcb97 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -2887,7 +2887,8 @@ 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); @@ -2904,23 +2905,30 @@ 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); @@ -2928,8 +2936,9 @@ 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; } } -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation