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 2262AC433F5 for ; Wed, 18 May 2022 13:00:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237405AbiERNAm (ORCPT ); Wed, 18 May 2022 09:00:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237425AbiERNAl (ORCPT ); Wed, 18 May 2022 09:00:41 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 512A01A6AE4; Wed, 18 May 2022 06:00:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=6rvVpjtewErevwtzxVWgKanKatH+lil9XQiGaNTaboY=; b=ThnAz/oFIZap4IArJner1pmcW3 6MJb8LhZ5nlzG/AhKU5YUmwufgHp2bWyyb94yxcxXrUBTN7Cl0dmA2z8CKpyzIK8v7TkyezC8WKNP p4BAlJjvwr25/AOq/K3pzMeuO66nCKb7HsqmmbeQtweeDVpo+my1JeYHtcVeuNXIzNV1wVA5LVb5o 6IoZcDm+xiE6JtFyotUMSu++E2VWulFO3SodIndd8ca0TPhnop8eZO2XeBJR+m96h41AWDR0iv+y0 ELyJaeXYcmM7NBeIeWyQVoyNbNex/DPS2tNs3gXLZ9tQfqQMbbiHixzQycBM9ELWJsqZeII6s0y3p CacIyhmg==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nrJHs-002CUG-Vm; Wed, 18 May 2022 13:00:25 +0000 Date: Wed, 18 May 2022 06:00:24 -0700 From: Christoph Hellwig To: Vivek Kumar Cc: corbet@lwn.net, catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, maz@kernel.org, axboe@kernel.dk, rafael@kernel.org, akpm@linux-foundation.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-pm@vger.kernel.org, linux-mm@kvack.org, len.brown@intel.com, pavel@ucw.cz, paulmck@kernel.org, bp@suse.de, keescook@chromium.org, songmuchun@bytedance.com, rdunlap@infradead.org, damien.lemoal@opensource.wdc.com, pasha.tatashin@soleen.com, tabba@google.com, ardb@kernel.org, tsoni@quicinc.com, quic_psodagud@quicinc.com, quic_svaddagi@quicinc.com, Prasanna Kumar Subject: Re: [RFC 2/6] PM: Hibernate: Add option to disable disk offset randomization Message-ID: References: <1652860121-24092-1-git-send-email-quic_vivekuma@quicinc.com> <1652860121-24092-3-git-send-email-quic_vivekuma@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1652860121-24092-3-git-send-email-quic_vivekuma@quicinc.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, May 18, 2022 at 01:18:37PM +0530, Vivek Kumar wrote: > Add a kernel parameter to disable the disk offset randomization > for SSD devices in which such feature is available at the > firmware level. This is helpful in improving hibernation > resume time. This patch just adds a global variable which is then entirely igored. But the idea of "randomizing" offsets on SSDs sounds like complete BS to start with. The whole job of the SSD is to remap from a random writable block device to difference physical blocks to deal with erases and wear leveling. In other words it really doesn't matter what offset your write to. That being said I could not actually find any code that does this randomization to start with, but that might just be my lack of grep skills. 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 132CCC433EF for ; Wed, 18 May 2022 13:01:29 +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=dfQ2aLN/SUZQnxgCUfhsUbubC7UEiXsRrNqapOk0vk0=; b=KS6o3CqAqH1zC7 nkcQ0ClPiwVtTF6dg9o0KbPmqwNClg26FcNw0aCX8PwRouz/lWEviifi9U9zfXMhZb5hSvKPweE9J 2IyF+fpfRnDZ1MU1EdEDWmVCwK8upvQTSICludB7HVxQGaVsnIBa7ipFqlBYYa/6LK2ywnkeJB/vv +PsjhqV73z1EMTPyL3Wz6h/xvCMN/BiQ1ewupGS3xnhcewelNZpW7pejCNkI7T2+Jypx/yl5T/xTD flWaMfjJWCXrs9Uy2bUXfqgivFRsiU3IRDxRXwK4Rs0D4EU+YXgstHRAZy/fJJt3HpOx0heXuhYE0 ZRcwnrV2Mn7LGAM0REcA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nrJHw-002CVd-E5; Wed, 18 May 2022 13:00:28 +0000 Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nrJHs-002CUG-Vm; Wed, 18 May 2022 13:00:25 +0000 Date: Wed, 18 May 2022 06:00:24 -0700 From: Christoph Hellwig To: Vivek Kumar Cc: corbet@lwn.net, catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, maz@kernel.org, axboe@kernel.dk, rafael@kernel.org, akpm@linux-foundation.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-pm@vger.kernel.org, linux-mm@kvack.org, len.brown@intel.com, pavel@ucw.cz, paulmck@kernel.org, bp@suse.de, keescook@chromium.org, songmuchun@bytedance.com, rdunlap@infradead.org, damien.lemoal@opensource.wdc.com, pasha.tatashin@soleen.com, tabba@google.com, ardb@kernel.org, tsoni@quicinc.com, quic_psodagud@quicinc.com, quic_svaddagi@quicinc.com, Prasanna Kumar Subject: Re: [RFC 2/6] PM: Hibernate: Add option to disable disk offset randomization Message-ID: References: <1652860121-24092-1-git-send-email-quic_vivekuma@quicinc.com> <1652860121-24092-3-git-send-email-quic_vivekuma@quicinc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1652860121-24092-3-git-send-email-quic_vivekuma@quicinc.com> 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 Wed, May 18, 2022 at 01:18:37PM +0530, Vivek Kumar wrote: > Add a kernel parameter to disable the disk offset randomization > for SSD devices in which such feature is available at the > firmware level. This is helpful in improving hibernation > resume time. This patch just adds a global variable which is then entirely igored. But the idea of "randomizing" offsets on SSDs sounds like complete BS to start with. The whole job of the SSD is to remap from a random writable block device to difference physical blocks to deal with erases and wear leveling. In other words it really doesn't matter what offset your write to. That being said I could not actually find any code that does this randomization to start with, but that might just be my lack of grep skills. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel