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 5DC33C02192 for ; Tue, 28 Jan 2025 15:30:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C56C3280216; Tue, 28 Jan 2025 10:30:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C07E0280200; Tue, 28 Jan 2025 10:30:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AA63F280216; Tue, 28 Jan 2025 10:30:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 859DA280200 for ; Tue, 28 Jan 2025 10:30:49 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 98ECBC1140 for ; Tue, 28 Jan 2025 15:30:48 +0000 (UTC) X-FDA: 83057248176.23.4FF5BAC Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) by imf18.hostedemail.com (Postfix) with ESMTP id 117AB1C0026 for ; Tue, 28 Jan 2025 15:30:45 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ivdYqZiY; spf=pass (imf18.hostedemail.com: domain of yosry.ahmed@linux.dev designates 91.218.175.181 as permitted sender) smtp.mailfrom=yosry.ahmed@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738078246; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=MpQv8Hh0xINXsVuX3lZlqa25GjQTW93nhOM7BZmZ9s0=; b=WAMeS8Xkl4YxfA3lF310WwxBljuGSC5X7GuQjpuxg7lfu8Ez3F297vlKxdcbi4V2uISYPm la0HKFWlAg4nq9ECkNuWamgZRtH/awiBgKj86A0OEZzp0cHlrVNppbcVqSuOAjbx3vw0c3 dMjROGFj0WFTCm/48SVwecYVLU9Iank= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ivdYqZiY; spf=pass (imf18.hostedemail.com: domain of yosry.ahmed@linux.dev designates 91.218.175.181 as permitted sender) smtp.mailfrom=yosry.ahmed@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1738078246; a=rsa-sha256; cv=none; b=z6HxU/k2Ae1ASw8m4ZuXizr01ZvPS6hY7nvsCUkPJBpCWOBl2dqpeqW5bt+ug1z0weae47 QgYtBQIz2PR+pxAhn2LkocqI+xHa5uWuNoIBIBnJUQShm9Q04h4skCUUNMDKaeiKQ+xGPz /mPnx3R12p/g393kMvpzmywwXnDf0pw= Date: Tue, 28 Jan 2025 15:30:38 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1738078243; h=from:from:reply-to:subject:subject: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=MpQv8Hh0xINXsVuX3lZlqa25GjQTW93nhOM7BZmZ9s0=; b=ivdYqZiY5EgeWAuXkLXRy8MtRDyIJ79frDYwuNdm9/VXZwFzq/49VMduUCcL3QzJC/rTIf ez0I2MKAQCbzh3ZFiebLpUNpwDnOzYHl0CQlFY6vP8d8ZhUIkyv1tigrh+tii+nfrk956g DClZGfQs/DfeQtemfy/ooU73tywvMj4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yosry Ahmed To: Vlastimil Babka Cc: Andrew Morton , Vitaly Wool , Miaohe Lin , Johannes Weiner , Nhat Pham , Chengming Zhou , Huacai Chen , Seth Jennings , Dan Streetman , WANG Xuerui , linux-mm@kvack.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev Subject: Re: [PATCH 1/2] mm: zbud: deprecate CONFIG_ZBUD Message-ID: References: <42b24914-719a-4ff1-9d77-f6517717344f@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42b24914-719a-4ff1-9d77-f6517717344f@suse.cz> X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 117AB1C0026 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: jwsfcykr5rukrxax4zuc6u75k9z19c6i X-HE-Tag: 1738078245-756348 X-HE-Meta: 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 HD40Cb27 f4B767GTvJRTN7r4V4QbgVDbS0btcrKUtNhtysmhTECPu1l0e0KsbpmjU6eTkW4+MEjfDpLa1pysUhayWvLXXsLasSby0X1Ri1AzhHzLBCj/7ZE+KQbUT+wClIs7538xVDxrqVzfzyqmwvQT2SsnRJPoSPe2bC+s3K/37gJIIzulKTJ70tpiltHodded4OmGQ2oiCY6yNtRXj32pxHJjtI8jPnyeYnu1+ozwurQGa4qqNmpqmWxGpeA1G4e5zESlfDkzrqglQYoonmZ9H9xUPuVhKdtciT/oo9xbAzlR0tHmlmmk= 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: List-Subscribe: List-Unsubscribe: On Tue, Jan 28, 2025 at 11:21:10AM +0100, Vlastimil Babka wrote: > On 1/28/25 00:58, Yosry Ahmed wrote: > > The zbud compressed pages allocator is rarely used, most users use > > zsmalloc. zbud consumes much more memory (only stores 1 or 2 compressed > > pages per physical page). The only advantage of zbud is a marginal > > performance improvement that by no means justify the memory overhead. > > > > Historically, zsmalloc had significantly worse latency than zbud and > > z3fold but offered better memory savings. This is no longer the case as > > shown by a simple recent analysis [1]. In a kernel build test on tmpfs > > in a limited cgroup, zbud 2-3% less time than zsmalloc, but at the cost > > of using ~32% more memory (1.5G vs 1.13G). The tradeoff does not make > > sense for zbud in any practical scenario. > > > > The only alleged advantage of zbud is not having the dependency on > > CONFIG_MMU, but CONFIG_SWAP already depends on CONFIG_MMU anyway, and > > zbud is only used by zswap. > > > > Following in the footsteps of [2], which deprecated z3fold, deprecated > > zbud as planned and remove it in a few cycles if no objections are > > raised from active users. > > > > Rename the user-visible config options so that users with CONFIG_ZBUD=y > > get a new prompt with explanation during make oldconfig. Also, remove > > CONFIG_ZBUD from defconfig. > > > > [1]https://lore.kernel.org/lkml/CAJD7tkbRF6od-2x_L8-A1QL3=2Ww13sCj4S3i4bNndqF+3+_Vg@mail.gmail.com/ > > [2]https://lore.kernel.org/lkml/20240904233343.933462-1-yosryahmed@google.com/ > > > > Signed-off-by: Yosry Ahmed > > Seems weird not to Cc the folks listed in MAINTAINERS for ZBUD? Unless their > addresses are known to bounce? Ugh I had them in the CC list, but I played around with it and probably lost them :/ Seth, Dan, apologies. > And ZRAM maintainers should also be Ccd? ZRAM does not use zbud, I can definitely CC them but I don't want to be a source of noise :)