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 1A742EE14D9 for ; Thu, 7 Sep 2023 09:40:46 +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:Date:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=E5QBRcFpSfyO537IkhXkW+sEcFoBaSf8Spr5Bj0gwuk=; b=1d4eujsi/QVtTh dOvdzOjfp1Dh4q5CNwJZh9pHAM3Fn7zkaTLpTy+n4VK8N6UUG9uSCYH2GzbVzy1DeO2WiGHokq2iy pc5rBef1X+mAntyirHSB1Nj33mEQBVbVf9CDDVEc51iWpqcCnnxtDaY8g3hm+wrukxpdx1xdao2ls bHjlUcxIKfw42SuOlStyCrlgTSYne2lFx7ul9zHsY8SiAsdzUFZ62t6qw7orCMI9kuT/koxAW1Rwb KpMEEcjZD2ONw12JhEXZ1UXmc4K++9eHHSVvXi5g6UO3QrakJBc+x2g2nHAAmtmWtozZjdt46YI3z V/UAZmixdRqA8vtOo8dA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qeBVE-00BhTw-0S; Thu, 07 Sep 2023 09:40:44 +0000 Received: from mail-lf1-x12f.google.com ([2a00:1450:4864:20::12f]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qeBVB-00BhTK-0q for kexec@lists.infradead.org; Thu, 07 Sep 2023 09:40:42 +0000 Received: by mail-lf1-x12f.google.com with SMTP id 2adb3069b0e04-502153ae36cso1128262e87.3 for ; Thu, 07 Sep 2023 02:40:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1694079639; x=1694684439; darn=lists.infradead.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=m2fdKFR8q9uEXLNSeU9tuN4gH8iEvFyeK5eSCmXl3rY=; b=DzOJCkhRVnD5xl53L7CgEZUTPx1kVnwbw1Yy1DJFEJMxLt4T6nfReEDx+vpfGbkt8W TpR041j1E6QQ1oErjlmtymKqsleAsmTKxv6Kmyqmq55+YthreqkugaxLv2/igj94m4Gb tyinwtSRgkGWaTKYCe5f4ZfrVs5L6tQtG7nYM04hkR7BcYeO0fYqgsdhtytK76RmWboZ FYk6qPLbRW6HK4WmxIMY93qBp8Ak4hkk4gIAH39RCH1LVawbPeHmIao3JQcBxSa2BlXg liNceAlrD2Y6Y9K050Cl/2RBDGGLGLsprs4LLmKvLw7G41q/uh/8x9BTH+73FDS+KKL/ Sa7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1694079639; x=1694684439; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=m2fdKFR8q9uEXLNSeU9tuN4gH8iEvFyeK5eSCmXl3rY=; b=TyeUl/IDfHd8D5J7fIcLzjPiHauiOYH77fEBaS1H2rQEBxrLRw4CoJofxf5+Xaxi05 uohw9MYpm7fYxnD5PuGyt8QTyUA8iL/7hqdGY9zvlETTKnBw1w0NS6t706D8DXCXPx3E g8Xpha7INFUZXWp1ykkkhPOqH/9PWy9LiqI2HAqDy4yIs7bGWDQYTU9lrb5jS4zw0bgv mktf1QoedUcNiPJwlKHTi0tyBLGqsxtiN4+GwetAXEBYaQfPg3JO3YUHZaX+DpCKxalj P+v1WZe/0tiHVInB39B1Gk5z5v/GMefoBdoBqX7d5SSjyQvlqZkUAk6PhWD3/e24J6wO Elqg== X-Gm-Message-State: AOJu0YyH8m/salXWXzS1RGLo45y6p5QDYHOKfSMHabHOq8moj0eRf3Ws 3Q3gqR3qnFyCIb6T6UguUFY= X-Google-Smtp-Source: AGHT+IGnVUxgJvZMlPBtKyIiXEz0zQ/L77txjqDYDTh1Sa3UGxaMrwFpLFqcHn1w07E0rmK4dukubA== X-Received: by 2002:ac2:52ab:0:b0:500:5d5c:ecc9 with SMTP id r11-20020ac252ab000000b005005d5cecc9mr4043445lfm.62.1694079639175; Thu, 07 Sep 2023 02:40:39 -0700 (PDT) Received: from pc636 (host-90-235-20-237.mobileonline.telia.com. [90.235.20.237]) by smtp.gmail.com with ESMTPSA id t16-20020a192d50000000b00501c6d78f11sm597800lft.298.2023.09.07.02.40.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Sep 2023 02:40:38 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Thu, 7 Sep 2023 11:40:36 +0200 To: Baoquan He Cc: "Uladzislau Rezki (Sony)" , k-hagio-ab@nec.com, lijiang@redhat.com, linux-mm@kvack.org, Andrew Morton , LKML , Lorenzo Stoakes , Christoph Hellwig , Matthew Wilcox , "Liam R . Howlett" , Dave Chinner , "Paul E . McKenney" , Joel Fernandes , Oleksiy Avramchenko , kexec@lists.infradead.org Subject: Re: [PATCH v2 4/9] mm: vmalloc: Remove global vmap_area_root rb-tree Message-ID: References: <20230829081142.3619-1-urezki@gmail.com> <20230829081142.3619-5-urezki@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230907_024041_338416_9DD34965 X-CRM114-Status: GOOD ( 28.00 ) X-BeenThere: kexec@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: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Thu, Sep 07, 2023 at 05:38:07PM +0800, Baoquan He wrote: > On 09/07/23 at 10:17am, Baoquan He wrote: > > Add Kazu and Lianbo to CC, and kexec mailing list > > > > On 08/29/23 at 10:11am, Uladzislau Rezki (Sony) wrote: > > > Store allocated objects in a separate nodes. A va->va_start > > > address is converted into a correct node where it should > > > be placed and resided. An addr_to_node() function is used > > > to do a proper address conversion to determine a node that > > > contains a VA. > > > > > > Such approach balances VAs across nodes as a result an access > > > becomes scalable. Number of nodes in a system depends on number > > > of CPUs divided by two. The density factor in this case is 1/2. > > > > > > Please note: > > > > > > 1. As of now allocated VAs are bound to a node-0. It means the > > > patch does not give any difference comparing with a current > > > behavior; > > > > > > 2. The global vmap_area_lock, vmap_area_root are removed as there > > > is no need in it anymore. The vmap_area_list is still kept and > > > is _empty_. It is exported for a kexec only; > > > > I haven't taken a test, while accessing all nodes' busy tree to get > > va of the lowest address could severely impact kcore reading efficiency > > on system with many vmap nodes. People doing live debugging via > > /proc/kcore will get a little surprise. > > > > Empty vmap_area_list will break makedumpfile utility, Crash utility > > could be impactd too. I checked makedumpfile code, it relys on > > vmap_area_list to deduce the vmalloc_start value. > > Except of the empty vmap_area_list, this patch looks good to me. > > We may need think of another way to export the vmalloc_start value or > deduce it in makedumpfile/Crash utility. And then remove the useless > vmap_area_list. I am not sure if we should remove vmap_area_list in this > patch because the empty value will cause breakage anyway. Otherwise, > > Reviewed-by: Baoquan He > Thanks for the review! -- Uladzislau Rezki _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec