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 E7D99C433EF for ; Fri, 7 Jan 2022 09:00:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7A6F66B0071; Fri, 7 Jan 2022 04:00:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 755FE6B0073; Fri, 7 Jan 2022 04:00:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 644BC6B0074; Fri, 7 Jan 2022 04:00:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0251.hostedemail.com [216.40.44.251]) by kanga.kvack.org (Postfix) with ESMTP id 55A1C6B0071 for ; Fri, 7 Jan 2022 04:00:34 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 015DB181E4CB8 for ; Fri, 7 Jan 2022 09:00:34 +0000 (UTC) X-FDA: 79002895146.11.5C8A9B0 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf07.hostedemail.com (Postfix) with ESMTP id 86F934000F for ; Fri, 7 Jan 2022 09:00:33 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 24CFD1F3A2; Fri, 7 Jan 2022 09:00:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1641546032; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=9ig5IiEWOoBShbVVLKjnlcWWj+KTg7Y8hxv8YDisw5s=; b=azeK60Hwa4gjEk7/3/CK0/YkNfN3ozmGMgfJ8kvjeqVWwwOZAOQ/Lutrrl+keH9pchj3QG qQk413bZp9arhr9FtD5jljEVLkXa7HqxhbWYhGx//HeTw09NwojUSB3vg2FgBnIf8g67nG aE4/RnBndC/Rw4J8e8NJOdGwoXD2rOw= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 8304BA3B83; Fri, 7 Jan 2022 09:00:31 +0000 (UTC) Date: Fri, 7 Jan 2022 10:00:31 +0100 From: Michal Hocko To: Yu Zhao Cc: Andrew Morton , Linus Torvalds , Andi Kleen , Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Jesse Barnes , Johannes Weiner , Jonathan Corbet , Matthew Wilcox , Mel Gorman , Michael Larabel , Rik van Riel , Vlastimil Babka , Will Deacon , Ying Huang , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, page-reclaim@google.com, x86@kernel.org, Konstantin Kharlamov Subject: Re: [PATCH v6 6/9] mm: multigenerational lru: aging Message-ID: References: <20220104202227.2903605-1-yuzhao@google.com> <20220104202227.2903605-7-yuzhao@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=azeK60Hw; spf=pass (imf07.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 86F934000F X-Stat-Signature: j4hgi3psnf98a1yektwjja89o778moeu X-HE-Tag: 1641546033-428309 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 Fri 07-01-22 09:55:09, Michal Hocko wrote: [...] > > In this case, lru_gen_mm_walk is small (160 bytes); it's per direct > > reclaimer; and direct reclaimers rarely come here, i.e., only when > > kswapd can't keep up in terms of the aging, which is similar to the > > condition where the inactive list is empty for the active/inactive > > lru. > > Well, this is not a strong argument to be honest. Kswapd being stuck > and the majority of the reclaim being done in the direct reclaim > context is a situation I have seen many many times. Also do not forget that memcg reclaim is effectivelly only direct reclaim. Not that the memcg reclaim indicates a global memory shortage but it can add up and race with the global reclaim as well. -- Michal Hocko SUSE Labs