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 A9431EB64D9 for ; Tue, 4 Jul 2023 18:03:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4867B2800A9; Tue, 4 Jul 2023 14:03:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 43793280096; Tue, 4 Jul 2023 14:03:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 325182800A9; Tue, 4 Jul 2023 14:03:09 -0400 (EDT) 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 1FB91280096 for ; Tue, 4 Jul 2023 14:03:09 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id EBFBD80378 for ; Tue, 4 Jul 2023 18:03:08 +0000 (UTC) X-FDA: 80974700856.18.FB4BB77 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf01.hostedemail.com (Postfix) with ESMTP id 267A64002B for ; Tue, 4 Jul 2023 18:03:06 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=YHpSDLiT; dmarc=none; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688493787; 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=DnSneZk2dwwUszQpTYSf7MYjJAwskKKHrxvlsvcy1u8=; b=NMOlzHcfpFUZo0LWeqbPnLhsc2XjAQ3y+YtUS37jT5L4NsS4Fq6bi42ctsod7bMn/KrAjm LhBWj2TSZHUoo8/Azy2XNDpAQs9UpWniDQuNl/DVLRRAhgevmqXFCdjFJN7XeGfgywC/QN BfuqeW5hjCzKWk0c3UWeLXfz7+LV5+U= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=YHpSDLiT; dmarc=none; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1688493787; a=rsa-sha256; cv=none; b=LSjCYUNzHweCVwrCD2xFSUv9Yv5aLUO6GesBkelYDkxmWuPclY85S3HHGUUL64by7jBG0Z GaNrdxHL7V55wwzYwxxPAwgK14Gt/jQQ3k3o18llJugvMrNZmUc0ptMeFAamKhB9KbOTro iP2/6UbY7awCmG7glHIQtS0MQMccBEA= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=DnSneZk2dwwUszQpTYSf7MYjJAwskKKHrxvlsvcy1u8=; b=YHpSDLiTOzNYTkPXom6tOnSnks 4KhFWeJZ2Zpl0oThz4UFqyR4LbiVqcZq86EvVWZT1K1oiV1asaN0bfGSa89P+EpnPhytYiqTuXhO6 aYXbM7N5LZ1D9X3LOUoJdGfk25FyBcOHy4jV0VW+bUqqLQgK8a+4F6v9aitNZCCc/XQFt1gfm8Dzy b0yVFhRqYTfMJuWOHtP6yP5xtKM0MW66onj1ecR1YjzVPCUF68y5fbuF+whKKO9EqyZg5lHNv5HyF N7nclX31FGTZNDzRWtJOyecHMI4g2CiijqUae68x76nA3CVggAume1r6bLvbR6qMN1j78HZiS8I30 W3x4463w==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qGkMi-009M8M-ER; Tue, 04 Jul 2023 18:03:04 +0000 Date: Tue, 4 Jul 2023 19:03:04 +0100 From: Matthew Wilcox To: Dave Chinner Cc: Andrew Morton , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jan Kara , Christoph Hellwig Subject: Re: [PATCH] writeback: Account the number of pages written back Message-ID: References: <20230628185548.981888-1-willy@infradead.org> <20230702130615.b72616d7f03b3ab4f6fc8dab@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 267A64002B X-Stat-Signature: h7nh8bdrqucnsp935akz7qwfu3u53b1f X-HE-Tag: 1688493786-503162 X-HE-Meta: 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 B7OCqSdG ICgzYwZZsc15atBGq72xSNhyb6UxIQdVI0MK7b0mFcNkRBxupZvS4V+tse8M3LO8OZqrPVzzONrU/lcfYuogPhne92LGh8B0UuUxKDwt4K7IafMtPKH+I1IJlTJQVPzvNXv8suZnRGxa46KUJj41/mGd0fBi2g64Gfm09zoY8/mzUrWUPnlu77SX/9zMV64UgN5Jg 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: On Tue, Jul 04, 2023 at 07:37:17AM +1000, Dave Chinner wrote: > On Mon, Jul 03, 2023 at 03:13:15AM +0100, Matthew Wilcox wrote: > > On Sun, Jul 02, 2023 at 01:06:15PM -0700, Andrew Morton wrote: > > > On Wed, 28 Jun 2023 19:55:48 +0100 "Matthew Wilcox (Oracle)" wrote: > > > > > > > nr_to_write is a count of pages, so we need to decrease it by the number > > > > of pages in the folio we just wrote, not by 1. Most callers specify > > > > either LONG_MAX or 1, so are unaffected, but writeback_sb_inodes() > > > > might end up writing 512x as many pages as it asked for. > > > > > > 512 is a big number, Should we backport this? > > > > I'm really not sure. Maybe? I'm hoping one of the bots comes up with a > > meaningful performance change as a result of this patch and we find out. > > XFS is the only filesystem this would affect, right? AFAIA, nothing > else enables large folios and uses writeback through > write_cache_pages() at this point... Good point. Still, Intel's 0day has squawked about a loss of performance when large folios have _stopped_ being used, so they are at least testing with XFS.