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 83660C43334 for ; Sun, 3 Jul 2022 05:41:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 04CE46B0073; Sun, 3 Jul 2022 01:41:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F3D756B0074; Sun, 3 Jul 2022 01:41:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E2CD66B0075; Sun, 3 Jul 2022 01:41:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id D46A16B0073 for ; Sun, 3 Jul 2022 01:41:28 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id AC32360FE3 for ; Sun, 3 Jul 2022 05:41:28 +0000 (UTC) X-FDA: 79644691056.07.C647C69 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) by imf11.hostedemail.com (Postfix) with ESMTP id 08FB24004F for ; Sun, 3 Jul 2022 05:41:27 +0000 (UTC) Received: by mail-yb1-f201.google.com with SMTP id w2-20020a25ef42000000b0066d68be3fbcso5247300ybm.13 for ; Sat, 02 Jul 2022 22:41:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=RCIHRsS3IZB8kUt7OF5p/9vX3y/w4XrPgB8Wt7R3ATo=; b=FluW4nHF5ePW57L+eIaWCPyz8I6gxRAS9RR4BzJQ2NXbWqpkD1fG0t2J+KOvMK/e27 T/q2CRqVRnagqLlvFmXIl46tZOQVnsZZt4gdPLxFUpj0uhrddkv6CufqoGMwxSd1Tfqv ASewp9ZWGq5MeYhuQJq74vw5Gv5v1dbCAP9QE0iWdvZm0AMdqJVgkh4ycJLjXGlbUmZ9 Hmormwnce55YBDX25VyWPP+RCqEj74QL6yTEg0X1Ad0E+OOBzWw5IJFJ08Gz4wXRiWwI 9EgxVSe2/QrzicBMubqbRjZM8+fA3vG+NffjJIFmEa713tQSIUnizwqakFnL2A/pIoY6 p1xg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=RCIHRsS3IZB8kUt7OF5p/9vX3y/w4XrPgB8Wt7R3ATo=; b=R/aYBvUeZxx9tBwkZ0B0sVq91YnEqC1B3rDMJbUhgAzSMgHy6oHcW0m1Lw2Zq58f1e Cz66YIP+sKCAjMsOsNQInOju40RwgOB6hGvLrOk7zdW0zqvvJV9HxRUmMdC6wX/Bjl3w 9ykvPmvK/E2wtJgQz/RVibxIKVHkdNLqGUxQF8WlA3WQJSwFhuuafvJZvk+J7i5jzz8x RO0qKLXd9ehFAqyWOwkZP8tqJ5NuBb4qraJ8bZrlqGjSt19+8VAxOWwISuFR+HPglzVM P8XQtlWvknaX5Oe+Fv62Qo4w/ePBeiTcigotmfyfU8lE497hCcCp5GEW0/vp+OgpgndQ CWXw== X-Gm-Message-State: AJIora+anfC3odE/LNtztVLEIAJVqjeB+TpGYsitun3ZdGuzNwIP9ar/ IoXtK2prIxAK6GIeOl8bOWlIDzK9IfyFWQ== X-Google-Smtp-Source: AGRyM1sg2G9UjPp4SBtqfXXQvPHtLDEJFpYYKi73xE+/sBeUyg/Z6zaE+cTAZGhd7AhxEPsCx+IU/l7aw/W5zQ== X-Received: from shakeelb.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:28b]) (user=shakeelb job=sendgmr) by 2002:a81:6f02:0:b0:31b:dd95:1ccf with SMTP id k2-20020a816f02000000b0031bdd951ccfmr25344701ywc.520.1656826887214; Sat, 02 Jul 2022 22:41:27 -0700 (PDT) Date: Sun, 3 Jul 2022 05:41:24 +0000 In-Reply-To: Message-Id: <20220703054124.f6goy5irvghc4knq@google.com> Mime-Version: 1.0 References: Subject: Re: [PATCH v2] mm: honor FGP_NOWAIT for page cache page allocation From: Shakeel Butt To: Jens Axboe Cc: Matthew Wilcox , linux-mm@kvack.org, Stefan Roesch Content-Type: text/plain; charset="us-ascii" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656826888; a=rsa-sha256; cv=none; b=lI3qPpE12l0WiqI9GbrPST0wQs+TEKE/J42oSKVt9AJWEqemkoTC3eGwod/KsUivNow7LD sciPgfZPjMj3+AlRSNdvNE5Fz8bcLjbK+tZK1qIqM4HRditsYlVqMgD+23hKVxg/KUGpmr fSLxdZVOp6DrasL9wFRajKVVt7TPrQ8= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=FluW4nHF; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf11.hostedemail.com: domain of 3ByzBYggKCIAwleoiipfksskpi.gsqpmry1-qqozego.svk@flex--shakeelb.bounces.google.com designates 209.85.219.201 as permitted sender) smtp.mailfrom=3ByzBYggKCIAwleoiipfksskpi.gsqpmry1-qqozego.svk@flex--shakeelb.bounces.google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656826888; 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=RCIHRsS3IZB8kUt7OF5p/9vX3y/w4XrPgB8Wt7R3ATo=; b=RDLhtrE6SNmVvkPbUnvlXcblAe10oRpe2E/ct38/ZeAQDgcaBOx3FXt3RYl2CqBe+bZfPl 9n1NzBw5xDL9oDkQ9NJGZCPwnyt8RFsFSGb5bRxEp5K3YXQ4ejAuJ12OEi61VsO1WcTwVF Bwzz6/EWOnmvrw8szpKIF7Dqty35dd0= X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 08FB24004F Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=FluW4nHF; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf11.hostedemail.com: domain of 3ByzBYggKCIAwleoiipfksskpi.gsqpmry1-qqozego.svk@flex--shakeelb.bounces.google.com designates 209.85.219.201 as permitted sender) smtp.mailfrom=3ByzBYggKCIAwleoiipfksskpi.gsqpmry1-qqozego.svk@flex--shakeelb.bounces.google.com X-Rspam-User: X-Stat-Signature: beihrhxz5rferotghqhufjep34sjm5em X-HE-Tag: 1656826887-121430 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000037, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Jul 02, 2022 at 09:43:32AM -0600, Jens Axboe wrote: > If we're creating a page cache page with FGP_CREAT but FGP_NOWAIT is > set, we should dial back the gfp flags to avoid frivolous blocking > which is trivial to hit in low memory conditions: > > [ 10.117661] __schedule+0x8c/0x550 > [ 10.118305] schedule+0x58/0xa0 > [ 10.118897] schedule_timeout+0x30/0xdc > [ 10.119610] __wait_for_common+0x88/0x114 > [ 10.120348] wait_for_completion+0x1c/0x24 > [ 10.121103] __flush_work.isra.0+0x16c/0x19c > [ 10.121896] flush_work+0xc/0x14 > [ 10.122496] __drain_all_pages+0x144/0x218 > [ 10.123267] drain_all_pages+0x10/0x18 > [ 10.123941] __alloc_pages+0x464/0x9e4 > [ 10.124633] __folio_alloc+0x18/0x3c > [ 10.125294] __filemap_get_folio+0x17c/0x204 > [ 10.126084] iomap_write_begin+0xf8/0x428 > [ 10.126829] iomap_file_buffered_write+0x144/0x24c > [ 10.127710] xfs_file_buffered_write+0xe8/0x248 > [ 10.128553] xfs_file_write_iter+0xa8/0x120 > [ 10.129324] io_write+0x16c/0x38c > [ 10.129940] io_issue_sqe+0x70/0x1cc > [ 10.130617] io_queue_sqe+0x18/0xfc > [ 10.131277] io_submit_sqes+0x5d4/0x600 > [ 10.131946] __arm64_sys_io_uring_enter+0x224/0x600 > [ 10.132752] invoke_syscall.constprop.0+0x70/0xc0 > [ 10.133616] do_el0_svc+0xd0/0x118 > [ 10.134238] el0_svc+0x78/0xa0 > > Clear IO, FS, and reclaim flags and mark the allocation as GFP_NOWAIT and > add __GFP_NOWARN to avoid polluting dmesg with pointless allocations > failures. A caller with FGP_NOWAIT must be expected to handle the > resulting -EAGAIN return and retry from a suitable context without NOWAIT > set. > > Signed-off-by: Jens Axboe Reviewed-by: Shakeel Butt