From: Bart Van Assche <bart.vanassche@sandisk.com>
To: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Hugh Dickins <hughd@google.com>,
Oleg Nesterov <oleg@redhat.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH] do_generic_file_read(): Fail immediately if killed
Date: Wed, 17 Aug 2016 09:23:46 -0700 [thread overview]
Message-ID: <55935013-1aae-3fe6-9579-dec34625961e@sandisk.com> (raw)
In-Reply-To: <20160817100156.GA6254@quack2.suse.cz>
On 08/17/2016 03:02 AM, Jan Kara wrote:
> On Tue 16-08-16 17:00:43, Bart Van Assche wrote:
>> If a fatal signal has been received, fail immediately instead of
>> trying to read more data.
>>
>> See also commit ebded02788b5 ("mm: filemap: avoid unnecessary
>> calls to lock_page when waiting for IO to complete during a read")
>
> The patch looks good to me. You can add:
>
> Reviewed-by: Jan Kara <jack@suse.cz>
>
> BTW: Did you see some real world impact of the change? If yes, it would be
> good to describe in the changelog.
Hello Jan,
Thanks for the review.
This patch has an impact on my tests. However, I do not yet have a full
root-cause analysis for what I observed in my tests. That is why I
hadn't mentioned any further details in the patch description.
While running fio on top of a filesystem (ext4 or xfs), dm-mpath and
the ib_srp driver I noticed that removing and restoring paths triggered
several types of hangs. The call trace of one of these hangs, the one
that made me look at do_generic_file_read(), can be found below. I'm
currently testing a block layer patch to see whether it resolves this
hang.
Bart.
kpartx D ffff8800409d3be8 0 16392 16355 0x00000000
Call Trace:
[<ffffffff8161f577>] schedule+0x37/0x90
[<ffffffff81623bcf>] schedule_timeout+0x27f/0x470
[<ffffffff8161e94f>] io_schedule_timeout+0x9f/0x110
[<ffffffff8161fd16>] bit_wait_io+0x16/0x60
[<ffffffff8161f9a6>] __wait_on_bit+0x56/0x80
[<ffffffff81152e2d>] wait_on_page_bit_killable+0xbd/0xc0
[<ffffffff81152f60>] generic_file_read_iter+0x130/0x770
[<ffffffff812134b0>] blkdev_read_iter+0x30/0x40
[<ffffffff811d267b>] __vfs_read+0xbb/0x130
[<ffffffff811d2a61>] vfs_read+0x91/0x130
[<ffffffff811d3de4>] SyS_read+0x44/0xa0
[<ffffffff81624fa5>] entry_SYSCALL_64_fastpath+0x18/0xa8
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next prev parent reply other threads:[~2016-08-17 16:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 0:00 Bart Van Assche
2016-08-17 10:01 ` Jan Kara
2016-08-17 16:23 ` Bart Van Assche [this message]
2016-08-17 13:48 ` Oleg Nesterov
2016-08-17 17:20 ` Michal Hocko
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