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 B19D4C433F5 for ; Wed, 18 May 2022 13:00:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 11C676B0072; Wed, 18 May 2022 09:00:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0CBC46B0073; Wed, 18 May 2022 09:00:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EFD5F6B0074; Wed, 18 May 2022 09:00:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id DD5236B0072 for ; Wed, 18 May 2022 09:00:46 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id B140B6069F for ; Wed, 18 May 2022 13:00:46 +0000 (UTC) X-FDA: 79478873292.10.E51353D Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf23.hostedemail.com (Postfix) with ESMTP id 830251400F8 for ; Wed, 18 May 2022 13:00:25 +0000 (UTC) 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 X-Stat-Signature: skxzf9ku6498ppr47subnb8sgedz4oas X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 830251400F8 Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b="ThnAz/oF"; spf=none (imf23.hostedemail.com: domain of BATV+240e8cd436ded551dd5d+6842+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+240e8cd436ded551dd5d+6842+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none X-Rspam-User: X-HE-Tag: 1652878825-593592 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 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.