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 X-Spam-Level: X-Spam-Status: No, score=-15.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90EB0C433E0 for ; Tue, 9 Feb 2021 14:28:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41F1164E4F for ; Tue, 9 Feb 2021 14:28:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231446AbhBIO2F (ORCPT ); Tue, 9 Feb 2021 09:28:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229908AbhBIO2B (ORCPT ); Tue, 9 Feb 2021 09:28:01 -0500 Received: from mail-il1-x134.google.com (mail-il1-x134.google.com [IPv6:2607:f8b0:4864:20::134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26459C061793 for ; Tue, 9 Feb 2021 06:27:13 -0800 (PST) Received: by mail-il1-x134.google.com with SMTP id g9so16256239ilc.3 for ; Tue, 09 Feb 2021 06:27:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=aq3qgdzINRFL23Dn3U54dtZVmlL/iGXyyjOyYitYchg=; b=Q8eJFyBOVIbD4ogb828BynFVMXVFH7Zvbd1xm5sf2+LB5zd+WDT3l59CLRjKS2ML6h bD+zrDDwbw7CtIv2yG6nq7s4FSgZf7uLmJ8hV98Em86K+9g7H3rVt2dm+PE3ZzCji0Kr 3yeM4T5g2cYIDBmZj3/qMSh63aBvf39S7Ol4r3LP2D0+mjuD9z1CkkPyNo4ClpiOudyp jgeS8SpP4Na0FIxSZYkD/Ejqp98EaPpoyKE+EeA+e89Zstf86PXP9FTjTahysL/Pqa/x HvETpChb95LlayAISbhSCOYU8MYV6RMqlC+t47qzG1seCouo/7zwqEcgSWjwkuVbYt3J djXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=aq3qgdzINRFL23Dn3U54dtZVmlL/iGXyyjOyYitYchg=; b=BoDynahl6ZLUBazWbzh2gJTDFPciv2ju5ItzeRyDHS3tAOQ3f60TBOawQm99SydjO7 SiIWXEjBdUqjGnjL2+Q6eMeVpi27rODia1sbM//Ytw39a6q2cwA1w1zTLRU11mktu64a HFjrsrTbBhylELELYxiHTERK0RmtwV5sBRF7vbpWXtQTTsgY0IliJ6p2fZ1ZpJM2ZJZs pX51rHUt6Kr8ONI0BREVFQNZmHTt3nSQh5hUYMkeuW+L4r4sJeLpRgXsOMnOqdao/oNA zFTHnsyIm+vuSBmkmY6SPVUe1Z6uN1HPqS2wjzFBEXy1H7eTBCigQnJGVJXh/8+YQxcF PqrA== X-Gm-Message-State: AOAM530DNGAkk0X3X/jMfy0NOIxmZUsi59zAAr8kuHxUgo8RcDqPPAuJ 9bkluzrPvX62Wf8xVxPWElkHlkpqKoEsuHU/ X-Google-Smtp-Source: ABdhPJwfwCe2fYUCEX2oziQhxEYkTu1eHBrgoBCkz+EjImveMu91Rq6576Dbv4B/2c+J4VmCai8m0w== X-Received: by 2002:a92:2e05:: with SMTP id v5mr21507028ile.241.1612880832503; Tue, 09 Feb 2021 06:27:12 -0800 (PST) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id b1sm3984200iob.42.2021.02.09.06.27.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Feb 2021 06:27:12 -0800 (PST) Subject: Re: [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org References: <20210209023008.76263-1-axboe@kernel.dk> <20210209023008.76263-3-axboe@kernel.dk> <20210209074814.GB1696555@infradead.org> From: Jens Axboe Message-ID: <07f67e83-ddfa-19f9-e4d5-f06a939b8840@kernel.dk> Date: Tue, 9 Feb 2021 07:27:11 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210209074814.GB1696555@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 2/9/21 12:48 AM, Christoph Hellwig wrote: > On Mon, Feb 08, 2021 at 07:30:07PM -0700, Jens Axboe wrote: >> For the generic page cache read helper, use the better variant of checking >> for the need to call filemap_write_and_wait_range() when doing O_DIRECT >> reads. This avoids falling back to the slow path for IOCB_NOWAIT, if there >> are no pages to wait for (or write out). >> >> Signed-off-by: Jens Axboe >> --- >> mm/filemap.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/mm/filemap.c b/mm/filemap.c >> index 6a58d50fbd31..c80acb80e8f7 100644 >> --- a/mm/filemap.c >> +++ b/mm/filemap.c >> @@ -2643,8 +2643,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) >> >> size = i_size_read(inode); >> if (iocb->ki_flags & IOCB_NOWAIT) { >> - if (filemap_range_has_page(mapping, iocb->ki_pos, >> - iocb->ki_pos + count - 1)) >> + if (filemap_range_needs_writeback(mapping, iocb->ki_pos, >> + iocb->ki_pos + count - 1)) > > Please avoid the overy long line, which is trivial to do by using the > normal two tab indent for the continuation. Sure, fixed. -- Jens Axboe