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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B21B3C433FE for ; Fri, 7 Jan 2022 09:06:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346359AbiAGJGT (ORCPT ); Fri, 7 Jan 2022 04:06:19 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:55142 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236746AbiAGJGR (ORCPT ); Fri, 7 Jan 2022 04:06:17 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 7DF231F39C; Fri, 7 Jan 2022 09:06:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1641546376; 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=/+rkleY2pIdK7PXNX7lUi9qQ2IGYdAkkl5TG1LGhbIQ=; b=sBVGhGr6l4U+RSvPC9eGfELzbL4s1aqGpH+E88SrDgSd/jnjr3QQB2+xND6183ZRKWEMeP Zj4IiU4WZKdPGQc224yRvWu9/WIRCgHUCwF8nMPSEhluQyxZyZx4Gf01omL4jcmSiuyOIZ nvJq0a2R8LkwcGxxmHToeJFaVmCY4aE= 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 BD8D9A3B8C; Fri, 7 Jan 2022 09:06:15 +0000 (UTC) Date: Fri, 7 Jan 2022 10:06:15 +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 5/9] mm: multigenerational lru: mm_struct list Message-ID: References: <20220104202227.2903605-1-yuzhao@google.com> <20220104202227.2903605-6-yuzhao@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220104202227.2903605-6-yuzhao@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 04-01-22 13:22:24, Yu Zhao wrote: > To exploit spatial locality, the aging prefers to walk page tables to > search for young PTEs. And this patch paves the way for that. > > An mm_struct list is maintained for each memcg, and an mm_struct > follows its owner task to the new memcg when this task is migrated. How does this work actually for the memcg reclaim? I can see you lru_gen_migrate_mm on the task migration. My concern is, though, that such a task leaves all the memory behind in the previous memcg (in cgroup v2, in v1 you can opt in for charge migration). If you move the mm to a new memcg then you age it somewhere where the memory is not really consumed. -- Michal Hocko SUSE Labs 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B3730C433F5 for ; Fri, 7 Jan 2022 09:07:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=MMu/VV5crVrB5Xv6Clr1n2vL9jl4PphSBzjlNnlwEBw=; b=OdVEZ0PFBulhjh Kesu6jlDw6mBUYt9FKsUkOO+JKL0zgmEo3PPKA0hpV3TeCmMX+pELBSoow7pMmXof8QWz+oRl4AcU VuJn0qTKZ8Ignsp5LBDm+eORjVzuC5x8FkfjbOAjUfW4A54cSXuO58Fah1aj1orKbJLypxLk9zU4X ZfWqqUjctogfm9M/ht7rQOZypATJQYgUGFbV0DBc+n0OYYldOEBEegEOe7lVEft+mu1a0l/KEjw8L 1dr0wooKS9JU4MndjYf8tgqlg/dWdbQ/NU2Gf4bbHZyxA4NG1Y1NHI07y//oj+LUOl0OU1x6rHDts 37AKsJ4CqDUde7OPFrwQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n5lCY-00302B-A4; Fri, 07 Jan 2022 09:06:22 +0000 Received: from smtp-out2.suse.de ([195.135.220.29]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1n5lCU-002zzd-1R for linux-arm-kernel@lists.infradead.org; Fri, 07 Jan 2022 09:06:19 +0000 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 7DF231F39C; Fri, 7 Jan 2022 09:06:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1641546376; 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=/+rkleY2pIdK7PXNX7lUi9qQ2IGYdAkkl5TG1LGhbIQ=; b=sBVGhGr6l4U+RSvPC9eGfELzbL4s1aqGpH+E88SrDgSd/jnjr3QQB2+xND6183ZRKWEMeP Zj4IiU4WZKdPGQc224yRvWu9/WIRCgHUCwF8nMPSEhluQyxZyZx4Gf01omL4jcmSiuyOIZ nvJq0a2R8LkwcGxxmHToeJFaVmCY4aE= 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 BD8D9A3B8C; Fri, 7 Jan 2022 09:06:15 +0000 (UTC) Date: Fri, 7 Jan 2022 10:06:15 +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 5/9] mm: multigenerational lru: mm_struct list Message-ID: References: <20220104202227.2903605-1-yuzhao@google.com> <20220104202227.2903605-6-yuzhao@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220104202227.2903605-6-yuzhao@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220107_010618_254268_29A75104 X-CRM114-Status: GOOD ( 12.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue 04-01-22 13:22:24, Yu Zhao wrote: > To exploit spatial locality, the aging prefers to walk page tables to > search for young PTEs. And this patch paves the way for that. > > An mm_struct list is maintained for each memcg, and an mm_struct > follows its owner task to the new memcg when this task is migrated. How does this work actually for the memcg reclaim? I can see you lru_gen_migrate_mm on the task migration. My concern is, though, that such a task leaves all the memory behind in the previous memcg (in cgroup v2, in v1 you can opt in for charge migration). If you move the mm to a new memcg then you age it somewhere where the memory is not really consumed. -- Michal Hocko SUSE Labs _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel