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 EC5F3C04A68 for ; Thu, 28 Jul 2022 11:10:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DFCE48E0001; Thu, 28 Jul 2022 07:10:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DAC5A6B0072; Thu, 28 Jul 2022 07:10:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C75278E0001; Thu, 28 Jul 2022 07:10:20 -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 B76076B0071 for ; Thu, 28 Jul 2022 07:10:20 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 72E8041494 for ; Thu, 28 Jul 2022 11:10:20 +0000 (UTC) X-FDA: 79736239800.06.7F96C2B Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf14.hostedemail.com (Postfix) with ESMTP id D931F1000D2 for ; Thu, 28 Jul 2022 11:10:19 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 4205F20767; Thu, 28 Jul 2022 11:10:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1659006618; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Ch7OpJ9togQrcIvktUHsyLTlf/K2VFQcctastF2/ugA=; b=FCWtvrX0enwGt/24CACMuJlboGjfqQhB9CUh53r1V4R7Q+P2f8G/Rz2cOKMtCEqqMhF4ac cVrAELjWf+1zwF57+XpH1ipr3AaAAOzR1+WOfzMSgaY0O0ZcLK3avwiSxXAwmXK490k04D ulOVOEKQ8Td6kbdIiLNEKwHL5adoNy8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1659006618; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Ch7OpJ9togQrcIvktUHsyLTlf/K2VFQcctastF2/ugA=; b=FUh7NyixVBdFFcjpzMMwj8qKd7dO71QTdNpxiDnX9HMHCJw+QKu+crfxmuo1KD6WUwxksP MjXSLHlpxT0XUMAA== Received: from quack3.suse.cz (unknown [10.163.43.118]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 97F522C141; Thu, 28 Jul 2022 11:10:17 +0000 (UTC) Received: by quack3.suse.cz (Postfix, from userid 1000) id 4F4C9A0668; Thu, 28 Jul 2022 13:10:16 +0200 (CEST) Date: Thu, 28 Jul 2022 13:10:16 +0200 From: Jan Kara To: Christoph Hellwig Cc: Bob Peterson , Andreas Gruenbacher , "Darrick J. Wong" , Damien Le Moal , Naohiro Aota , Johannes Thumshirn , cluster-devel@redhat.com, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman Subject: Re: remove iomap_writepage v2 Message-ID: <20220728111016.uwbaywprzkzne7ib@quack3> References: <20220719041311.709250-1-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220719041311.709250-1-hch@lst.de> ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=FCWtvrX0; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=FUh7Nyix; spf=pass (imf14.hostedemail.com: domain of jack@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=jack@suse.cz; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659006620; a=rsa-sha256; cv=none; b=NcnroRLxNDkkY893s9yHD0gTQzQzrguJ5gGzMTVE4dovXkdIX5OhfzhAl7bvyxzlGn1uJ8 +UwqIqMZQ/UkuH2FMRwT4cyzGoKMgnT89gOhwQbTrYYivSs6+veGCMAYyMGuYhljL/3bT5 +rBmppbXYzpbpiV7Kx0NJsNCzjuiSLI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659006620; 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=Ch7OpJ9togQrcIvktUHsyLTlf/K2VFQcctastF2/ugA=; b=hYJkmq1oTl6tVGZRNJMJoTQA+IVEb1HCefvBkU4R9JpElG8ji7+s3yCYk1FeI/MGrG+WC5 mbSTlYYCLm3cOtvXntqX23aBf73gTH0K1egDwV40OGQbUeIs5JKFBJevcWkG3+AQfA/Mk7 gUv8SW3AzZ4tzEbIxj09A2wUwv42zJw= Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=FCWtvrX0; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=FUh7Nyix; spf=pass (imf14.hostedemail.com: domain of jack@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=jack@suse.cz; dmarc=none X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D931F1000D2 X-Stat-Signature: o6et4b15fmbne7e1jts36kno7zej4ijk X-HE-Tag: 1659006619-813938 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: Hi Christoph! On Tue 19-07-22 06:13:07, Christoph Hellwig wrote: > this series removes iomap_writepage and it's callers, following what xfs > has been doing for a long time. So this effectively means "no writeback from page reclaim for these filesystems" AFAICT (page migration of dirty pages seems to be handled by iomap_migrate_page()) which is going to make life somewhat harder for memory reclaim when memory pressure is high enough that dirty pages are reaching end of the LRU list. I don't expect this to be a problem on big machines but it could have some undesirable effects for small ones (embedded, small VMs). I agree per-page writeback has been a bad idea for efficiency reasons for at least last 10-15 years and most filesystems stopped dealing with more complex situations (like block allocation) from ->writepage() already quite a few years ago without any bug reports AFAIK. So it all seems like a sensible idea from FS POV but are MM people on board or at least aware of this movement in the fs land? Added a few CC's for that. Honza > Changes since v1: > - clean up a printk in gfs2 > > Diffstat: > fs/gfs2/aops.c | 26 -------------------------- > fs/gfs2/log.c | 5 ++--- > fs/iomap/buffered-io.c | 15 --------------- > fs/zonefs/super.c | 8 -------- > include/linux/iomap.h | 3 --- > 5 files changed, 2 insertions(+), 55 deletions(-) -- Jan Kara SUSE Labs, CR