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Wed, 19 Feb 2020 14:57:21 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1j4GUC-0005gh-AV; Wed, 19 Feb 2020 14:57:20 +1100 Date: Wed, 19 Feb 2020 14:57:20 +1100 From: Dave Chinner To: Matthew Wilcox Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org Subject: Re: [PATCH v6 00/19] Change readahead API Message-ID: <20200219035720.GI10776@dread.disaster.area> References: <20200217184613.19668-1-willy@infradead.org> <20200218045633.GH10776@dread.disaster.area> <20200218134230.GN7778@bombadil.infradead.org> <20200218212652.GR10776@dread.disaster.area> <20200219034525.GH10776@dread.disaster.area> <20200219034832.GL24185@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200219034832.GL24185@bombadil.infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=W5xGqiek c=1 sm=1 tr=0 a=zAxSp4fFY/GQY8/esVNjqw==:117 a=zAxSp4fFY/GQY8/esVNjqw==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=IkcTkHD0fZMA:10 a=l697ptgUJYAA:10 a=7-415B0cAAAA:8 a=4gE3ddVfANxGN4fhDGwA:9 a=QEXdDO2ut3YA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Content-Transfer-Encoding: quoted-printable 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, Feb 18, 2020 at 07:48:32PM -0800, Matthew Wilcox wrote: > On Wed, Feb 19, 2020 at 02:45:25PM +1100, Dave Chinner wrote: > > On Wed, Feb 19, 2020 at 08:26:52AM +1100, Dave Chinner wrote: > > > On Tue, Feb 18, 2020 at 05:42:30AM -0800, Matthew Wilcox wrote: > > > > On Tue, Feb 18, 2020 at 03:56:33PM +1100, Dave Chinner wrote: > > > > > Latest version in your git tree: > > > > >=20 > > > > > $ =E2=96=B6 glo -n 5 willy/readahead > > > > > 4be497096c04 mm: Use memalloc_nofs_save in readahead path > > > > > ff63497fcb98 iomap: Convert from readpages to readahead > > > > > 26aee60e89b5 iomap: Restructure iomap_readpages_actor > > > > > 8115bcca7312 fuse: Convert from readpages to readahead > > > > > 3db3d10d9ea1 f2fs: Convert from readpages to readahead > > > > > $ > > > > >=20 > > > > > merged into a 5.6-rc2 tree fails at boot on my test vm: > > > > >=20 > > > > > [ 2.423116] ------------[ cut here ]------------ > > > > > [ 2.424957] list_add double add: new=3Dffffea000efff4c8, pre= v=3Dffff8883bfffee60, next=3Dffffea000efff4c8. > > > > > [ 2.428259] WARNING: CPU: 4 PID: 1 at lib/list_debug.c:29 __= list_add_valid+0x67/0x70 > > > > > [ 2.457484] Call Trace: > > > > > [ 2.458171] __pagevec_lru_add_fn+0x15f/0x2c0 > > > > > [ 2.459376] pagevec_lru_move_fn+0x87/0xd0 > > > > > [ 2.460500] ? pagevec_move_tail_fn+0x2d0/0x2d0 > > > > > [ 2.461712] lru_add_drain_cpu+0x8d/0x160 > > > > > [ 2.462787] lru_add_drain+0x18/0x20 > > > >=20 > > > > Are you sure that was 4be497096c04 ? I ask because there was a > > >=20 > > > Yes, because it's the only version I've actually merged into my > > > working tree, compiled and tried to run. :P > > >=20 > > > > version pushed to that git tree that did contain a list double-ad= d > > > > (due to a mismerge when shuffling patches). I noticed it and fix= ed > > > > it, and 4be497096c04 doesn't have that problem. I also test with > > > > CONFIG_DEBUG_LIST turned on, but this problem you hit is going to= be > > > > probabilistic because it'll depend on the timing between whatever= other > > > > list is being used and the page actually being added to the LRU. > > >=20 > > > I'll see if I can reproduce it. > >=20 > > Just updated to a current TOT Linus kernel and your latest branch, > > and so far this is 100% reproducable. > >=20 > > Not sure how I'm going to debug it yet, because it's init that is > > triggering it.... >=20 > Eric found it ... Yeah, just saw that and am applying his patch to test it... > still not sure why I don't see it. No readahead configured on your device? Cheers, Dave. --=20 Dave Chinner david@fromorbit.com