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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B879C433FE for ; Fri, 7 Jan 2022 09:00:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346300AbiAGJAe (ORCPT ); Fri, 7 Jan 2022 04:00:34 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:54206 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236362AbiAGJAd (ORCPT ); Fri, 7 Jan 2022 04:00:33 -0500 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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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