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 DF4B0CA0ED3 for ; Mon, 2 Sep 2024 09:01:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5028F8D00AC; Mon, 2 Sep 2024 05:01:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4881D8D0065; Mon, 2 Sep 2024 05:01:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 329628D00AC; Mon, 2 Sep 2024 05:01:55 -0400 (EDT) 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 0FFC38D0065 for ; Mon, 2 Sep 2024 05:01:55 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 7B7B5121B53 for ; Mon, 2 Sep 2024 09:01:54 +0000 (UTC) X-FDA: 82519205748.10.C80FF72 Received: from mail-qv1-f51.google.com (mail-qv1-f51.google.com [209.85.219.51]) by imf11.hostedemail.com (Postfix) with ESMTP id 600DE40035 for ; Mon, 2 Sep 2024 09:01:52 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=fztTU6MX; spf=pass (imf11.hostedemail.com: domain of laoar.shao@gmail.com designates 209.85.219.51 as permitted sender) smtp.mailfrom=laoar.shao@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=1725267665; 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=ynRjrJnf/caknOdrqHKVGwTxMwIA5RzjX7iPoNekIHI=; b=7D0XHRwKz5L1eFyB+U7sDUVqWsU7D+xsncXlxhgqXRi2npVliSGZNKbVU/GE1lovNMfalk XE5Q48xQKILao/19G7Un8zLkpkdHKPzymlcSSSp/ODpdF0hm7UpjcKfbJa/q/ssec3rCKr dRr6Ya6TJP/M03oPnyAdJKJN6WqAB5k= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=fztTU6MX; spf=pass (imf11.hostedemail.com: domain of laoar.shao@gmail.com designates 209.85.219.51 as permitted sender) smtp.mailfrom=laoar.shao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1725267665; a=rsa-sha256; cv=none; b=tmst0kkGP84GmPOQEa27/PA2SbVKxlzeK2c+vi+IaCKWWBP0QGBCQ8YXGYELPucXPXqz6l bADYBXpkMw556OrlxKMTmuEbIJgiKa00SLcPP4H1J51Yarv0oWVFQn7w0HJnC/5lohRPbr WnqlNX3zNQ1LDagYOqucIK9UGflcOVQ= Received: by mail-qv1-f51.google.com with SMTP id 6a1803df08f44-6c3552ce7faso17071066d6.1 for ; Mon, 02 Sep 2024 02:01:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1725267711; x=1725872511; 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=ynRjrJnf/caknOdrqHKVGwTxMwIA5RzjX7iPoNekIHI=; b=fztTU6MXkKJ7sk6kbH40drK5fosfELv+O057io7PqM914hLGqJ0naQjy5vGmVdo6QK Nhekf7t6I45G7M0KNPMuV8HQs6pVx6Do4Vb0kViPuTY2T/1HWybwuBXtv83Y1ZHrSh9q SxA05ldyb5sFTJReeploCXLk2VaE4/tHeAMqrjj7gDCbEkUH/KRx+lgtNHMkHDICg0cL xmavAI9xGasNdxtY9HLCIE2ngvrE92HUp/d2GR8ypavQ2u+N8I6aElUschhqPKwwjAer fX0D9lfITHkGMu4iOxnGM20q0Ww9z+W1CT5Ds0P0oXcLRSrBGYk6FROp9ufoSo/B7xUR OqXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725267711; x=1725872511; 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=ynRjrJnf/caknOdrqHKVGwTxMwIA5RzjX7iPoNekIHI=; b=B8NrHwKwgipvW9nn16o2z/XYv5GrzlCZX++RmSnBTD9GKfEZi9Jg3QV3vgwhfLSdPT 9vlvyi2Q+XcbnypNz7Fm95CWaoL8HOlPSGxbe+gHVHn0WY6x37LTL62ssEN/5dMCgU06 v0wZvgx40Nnw2N0xfXVHwvk/OoUl2g+geNZUAjd08zDCaAyASu9FXJqdM2YZy2wSSv7I 38mxVLHlmHpXfHzum+Rrpd5CHziiDm7k56bAIxZDhHhxDSBnHzHHNIK/yE4COgD6PYOG kdKuggBqm42HJwWwW2Gd34CCdHzHpt8u7jR0wtdUuQp31HyQwBHGw/qKLom6eZaptsvt edeQ== X-Forwarded-Encrypted: i=1; AJvYcCVnChvnRTuCifQqfkAQzZ5szdx4cEcJQjI1MfihAVUHunJpNrbkYCep4k787Ig/9qEqSEAOpCrxPg==@kvack.org X-Gm-Message-State: AOJu0YxLCl8f1YgyZ/62LQZ3T4kC6NJyF4ckxSMV7kQFayn9Dxwec46P yANoIAIHyeu+EIjHgAYxCNjYecatDNDlqro6FpLPlO4XSS/6mLESNDWgVL2ag9/gm5hcoILS1lJ SaSbnYH1Ppn3hDavM+IYztQP4iD0= X-Google-Smtp-Source: AGHT+IELCIzq8aGAuBTY7sWBevW03eMyKRara0e3UrDynu2DH3Tlc7UV5ru2SiwfFawaiuHtoGIA7wlXcThU81HRLSI= X-Received: by 2002:a05:6214:f69:b0:6b5:2062:dd5c with SMTP id 6a1803df08f44-6c33f33be5fmr290491226d6.8.1725267711323; Mon, 02 Sep 2024 02:01:51 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Yafang Shao Date: Mon, 2 Sep 2024 17:01:12 +0800 Message-ID: Subject: Re: [PATCH] bcachefs: Switch to memalloc_flags_do() for vmalloc allocations To: Michal Hocko Cc: Dave Chinner , Kent Overstreet , Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Chinner Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 600DE40035 X-Stat-Signature: 1985z74rqtto5h4af7o7xihowm6yqw3b X-HE-Tag: 1725267712-343427 X-HE-Meta: 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 s5+oL7VV 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.001183, 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, Sep 2, 2024 at 4:11=E2=80=AFPM Michal Hocko wrote= : > > On Mon 02-09-24 11:02:50, Yafang Shao wrote: > > On Sun, Sep 1, 2024 at 11:35=E2=80=AFAM Dave Chinner wrote: > [...] > > > AIUI, the memory allocation looping has back-offs already built in > > > to it when memory reserves are exhausted and/or reclaim is > > > congested. > > > > > > e.g: > > > > > > get_page_from_freelist() > > > (zone below watermark) > > > node_reclaim() > > > __node_reclaim() > > > shrink_node() > > > reclaim_throttle() > > > > It applies to all kinds of allocations. > > > > > > > > And the call to recalim_throttle() will do the equivalent of > > > memalloc_retry_wait() (a 2ms sleep). > > > > I'm wondering if we should take special action for __GFP_NOFAIL, as > > currently, it only results in an endless loop with no intervention. > > If the memory allocator/reclaim is trashing on couple of remaining pages > that are easy to drop and reallocated again then the same endless loop > is de-facto the behavior for _all_ non-costly allocations. All of them > will loop. This is not really great but so far we haven't really > developed a reliable thrashing detection that would suit all potential > workloads. There are some that simply benefit from work not being lost > even if the cost is a severe performance penalty. A general conclusion > has been that workloads which would rather see OOM killer triggering > early should implement that policy in the userspace. We have PSI, > refault counters and other tools that could be used to detect > pathological patterns and trigger workload specific action. Indeed, we're currently working on developing that policy. > > I really do not see why GFP_NOFAIL should be any special in this > specific case. I believe there's no way to stop it from looping, even if you implement a sophisticated user space OOM killer. ;) -- Regards Yafang