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=-8.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 49AE6C432BE for ; Mon, 30 Aug 2021 10:11:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DCFA660C40 for ; Mon, 30 Aug 2021 10:11:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DCFA660C40 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 8001D6B0071; Mon, 30 Aug 2021 06:11:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B08D6B0072; Mon, 30 Aug 2021 06:11:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69F8E8D0001; Mon, 30 Aug 2021 06:11:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0218.hostedemail.com [216.40.44.218]) by kanga.kvack.org (Postfix) with ESMTP id 5D5366B0071 for ; Mon, 30 Aug 2021 06:11:31 -0400 (EDT) Received: from smtpin34.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id F1E09181AF5D8 for ; Mon, 30 Aug 2021 10:11:30 +0000 (UTC) X-FDA: 78531329940.34.5D55509 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf16.hostedemail.com (Postfix) with ESMTP id 711E3F00008E for ; Mon, 30 Aug 2021 10:11:30 +0000 (UTC) Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 18FE122113; Mon, 30 Aug 2021 10:11:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1630318289; h=from:from:reply-to: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=AJ1hz0iq6S45sTbD6okU7tBzH0QgE93nbBtJ8pDyR4U=; b=m+yizlBkxYFIBtEZmki4vWFvhuKLTglJPAZNV4Z5e9y5Rw/kDsPSMhqjCrwgZpzePo81rQ 2lu9BbAIElOjHhf550UkPSNIIdw4vPgmVBzLXTtGdAO7RdxBytgmaERfVE1HL5lXgOcx8q qPP7RtPulx7k3SGiNimxaCTCY+/3XQk= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1630318289; h=from:from:reply-to: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=AJ1hz0iq6S45sTbD6okU7tBzH0QgE93nbBtJ8pDyR4U=; b=7V1sCrVl5hoCrIRMc6CwEaBt9wbAwalLV2AGcIiKGzl/s0rgZNYOoMIbCdOt6U6x6yGw7v HspC6Pe9JbRLLgBQ== Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id D303513670; Mon, 30 Aug 2021 10:11:28 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id EIAzMtCuLGHpQQAAGKfGzw (envelope-from ); Mon, 30 Aug 2021 10:11:28 +0000 Message-ID: Date: Mon, 30 Aug 2021 12:11:28 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.0.2 Content-Language: en-US To: Mike Kravetz , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Michal Hocko , Oscar Salvador , Zi Yan , Muchun Song , Naoya Horiguchi , David Rientjes , Hillf Danton References: <20210816224953.157796-1-mike.kravetz@oracle.com> <20210816162749.22b921a61156a091f3e1d14d@linux-foundation.org> <20210816184611.07b97f4c26b83090f5d48fab@linux-foundation.org> <10d86c18-f0cf-395f-4209-17ac71b9fc03@oracle.com> <2d826470-d345-0196-1359-b79ed08dfc66@oracle.com> From: Vlastimil Babka Subject: Re: [PATCH RESEND 0/8] hugetlb: add demote/split page functionality In-Reply-To: <2d826470-d345-0196-1359-b79ed08dfc66@oracle.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=m+yizlBk; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=7V1sCrVl; spf=pass (imf16.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.28 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-Stat-Signature: 4ym45fbwbj3wisws8aoh8euaud8i8rqt X-Rspamd-Queue-Id: 711E3F00008E X-Rspamd-Server: rspam04 X-HE-Tag: 1630318290-785764 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 8/28/21 01:04, Mike Kravetz wrote: > On 8/27/21 10:22 AM, Vlastimil Babka wrote: > I 'may' have been over stressing the system with all CPUs doing file > reads to fill the page cache with clean pages. I certainly need to > spend some more debug/analysis time on this. Hm that *could* play a role, as these will allow reclaim to make progress, but also the reclaimed pages might be stolen immediately and compaction will return COMPACT_SKIPPED and in should_compact_retry() we might go through this code path: /* * compaction was skipped because there are not enough order-0 pages * to work with, so we retry only if it looks like reclaim can help. */ if (compaction_needs_reclaim(compact_result)) { ret = compaction_zonelist_suitable(ac, order, alloc_flags); goto out; } where compaction_zonelist_suitable() will return true because it appears reclaim can free pages to allow progress. And there are no max retries applied for this case. With the reclaim and compaction tracepoints it should be possible to confirm this scenario.