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 A0D3EC02190 for ; Tue, 28 Jan 2025 18:09:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2BB06280243; Tue, 28 Jan 2025 13:09:46 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2695D280222; Tue, 28 Jan 2025 13:09:46 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0BCD0280243; Tue, 28 Jan 2025 13:09:46 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id D8C25280222 for ; Tue, 28 Jan 2025 13:09:45 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 866461C6CC1 for ; Tue, 28 Jan 2025 18:09:45 +0000 (UTC) X-FDA: 83057648730.05.9C82466 Received: from mail-qv1-f54.google.com (mail-qv1-f54.google.com [209.85.219.54]) by imf01.hostedemail.com (Postfix) with ESMTP id 99B2540014 for ; Tue, 28 Jan 2025 18:09:43 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="e/MMGj4M"; spf=pass (imf01.hostedemail.com: domain of nphamcs@gmail.com designates 209.85.219.54 as permitted sender) smtp.mailfrom=nphamcs@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738087783; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=yEwFCY/pJT4/bZXkcRLInfXta1s4/pTUOYsv/SpFEOk=; b=5H461QX025vv/haJJuCqi9ouQY/rm7Z1NwQTSJ6wzG9OneLNceYaiT4Jo9VIo+dHzqFzb5 7kkUhZu+iOlSmFgKCQ034Dpm+kEwkRBtuhA+snKTSjV9awmEi+NJHFv08pfEZZ8GsRdGlu mENoL8l1KMHn3Dem1bW9mCtqFwPeBt8= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="e/MMGj4M"; spf=pass (imf01.hostedemail.com: domain of nphamcs@gmail.com designates 209.85.219.54 as permitted sender) smtp.mailfrom=nphamcs@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1738087783; a=rsa-sha256; cv=none; b=GoPxj1IhliOmqxqfqv9sTfZEKCGRs338r8q4YwvPzYPogzTcdue4ruIETZkcIZnYbMpw2N 6VwVjRwjQ3IYtZj4mb7Ah/4SsRGd1QnCPJ8H3SzgBiKYAjPlnKMwMox/20cP9kSkFr9/At ABaVk6S7vgJbOuo6mzqvSrlAy33NTxQ= Received: by mail-qv1-f54.google.com with SMTP id 6a1803df08f44-6d8f65ef5abso47399956d6.3 for ; Tue, 28 Jan 2025 10:09:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1738087783; x=1738692583; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=yEwFCY/pJT4/bZXkcRLInfXta1s4/pTUOYsv/SpFEOk=; b=e/MMGj4MorCSYiiK3/4N82+R6mLVXnYaGNOZJSD/+sIx4I0VLzvlWFTqi5ViiMk+b9 0ER0AsjaluXe1o3IaJcLSETG7BNd3KczMv5mmvB/LvJcBiNMXX3kPwg+4vWOEFxi7S8/ GY2DhosgTm5/pGwyt3Gt8bJfJBCywMw8S6kGdDS2gYKcX2NArtCoO5y57fajhtaet70G lMqu0/eHqGhqI9TTH0XgqFP9gKstBOdu/6707GE2IyyWcRyr5Eh1DmTZ7WXpx2vnS/xr q3vRBjss3O6dWaAy3wsjUfl/oYmGdQWgV0g/c65o7vgmTquxCx7+FM7hYj21N1oM1UKi QfoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738087783; x=1738692583; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=yEwFCY/pJT4/bZXkcRLInfXta1s4/pTUOYsv/SpFEOk=; b=IUXi0tMR3Fmmv9r3prRoS2VaCNJ8ch0D2Mzjkv1y9myXAghg6pWInWPUEZZ98t+3zY gTUJYsIYwBft8ZCkABca5+znJCd7hBVB1O4Yujg8OAo89+dANzgdSzzHPv4QwJUqrfcE SGzYgigm/8QjjLSxr6MciZSsqa7O/RzWtH4vPOVqo2ck9DZzA4TmIEPqXNhj4Q9sVfOd pVnOeS4qYmfF/Vbdj2bMHy1gv0VYV89iWKUsOLOzeT8B+AiHmzBkEUtcBPAb4T9bGlpw nxURTs9XdEwgqCPbrTk8tDFvtdyPTQhdvA6wAK9Y9uATAwT7ZXLJextmp7L7sNV1jfqY F2/g== X-Forwarded-Encrypted: i=1; AJvYcCVb8RIZG34cORPrgaL8OGwSWkoOe5BviIqhSSy4T8lyV5nmgrgyGi0VEeCv+XzStXV+GlcGC20kRQ==@kvack.org X-Gm-Message-State: AOJu0YzrBPxcveQ3DcbkR2MbYJEB6fdkNfvhQKywTHb7EIe9BswDYCF1 K5lg152qYIDf7BQE0z6lCfS1IhHpGHQUDDkH5ggWOGffnkL6fh5iGaoJ0vqCS6ebclOheyv02Se B3n7pIizWpoVyNP9q+vf2zGM3k0g= X-Gm-Gg: ASbGnctkJJY7vr4iHySCANtVo1JckZXRLLdyuYIDss7R5BIc5CT3X/qQxEcOLjDvtbV dj0SFsUSudOGc0WT1JiJe/vMf5PcPU6PYbN6TVPkL+P3DgSHJMSE9ItdKlqYxTZVS4SoIDXONK4 8x1dNkIaAh4VIk6kL/md5Bw5PzHTPw X-Google-Smtp-Source: AGHT+IG7UfqpPGCJCmbndDDQ4XMO5xXhq8xrLicUYVN5lp6xx2c3RvaA80mPe3ws+o/VEYVO6Zh8T8zjcPihfeLh8T8= X-Received: by 2002:a05:6214:2a4e:b0:6cb:d4e6:2507 with SMTP id 6a1803df08f44-6e243bf84d9mr2433856d6.22.1738087782659; Tue, 28 Jan 2025 10:09:42 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Nhat Pham Date: Tue, 28 Jan 2025 10:09:31 -0800 X-Gm-Features: AWEUYZnq0DAriMkDKIu3OIjdc4uUYsYkcWLq1_qBF1N2DfOtP7hO90g3QQlIXnA Message-ID: Subject: Re: [PATCH 1/2] mm: zbud: deprecate CONFIG_ZBUD To: Yosry Ahmed Cc: Andrew Morton , Vitaly Wool , Miaohe Lin , Johannes Weiner , Chengming Zhou , Huacai Chen , WANG Xuerui , linux-mm@kvack.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 99B2540014 X-Stat-Signature: c1of6e6ueh9578u7zpobjsp48yk8uqma X-Rspam-User: X-HE-Tag: 1738087783-114456 X-HE-Meta: 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 dg41Zyya EtjQ64jd3WqTtxh1e8UExX7vlA0ljsLnbiGjvbwL09Ce6G4+nesUNnB44HgGSwBNVoziuArfViBlemYwmfs58TPZyGDijf04rQnTGTNwZeaIBa8eRlnOJlZJdf35xBdvl65RnB3+B4a1FZjxhGLvtqk/W6WZ5lOB72SoDcUOZl5xV1kQPCH+O/0IS4puWF3OtjPyGJ9u9mmN7r0u5YpCxwzi6Mknakje8UdKA3gFCD6z4Ybzpqti9cdV4yUkpxURvS1zZw0Lzie9zR6FpZqOjMhBOy4j+rG2KFaYJ277UaSrRP58QoTeYn1Se4kC/XHQiX67Kr+p7XZTbmuR4JewSNamqFq4ylJYI1++vCiZEFcZ02nYIu7RCVsT/d0ajoqYS8Cj76M+HKM9Tf4nqNbLabShwxw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.032287, 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 Mon, Jan 27, 2025 at 3:58=E2=80=AFPM 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=3Dy > 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=3D2Ww13sCj4S3i4= bNndqF+3+_Vg@mail.gmail.com/ > [2]https://lore.kernel.org/lkml/20240904233343.933462-1-yosryahmed@google= .com/ > > Signed-off-by: Yosry Ahmed Acked-by: Nhat Pham