From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Tejun Heo <tj@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>, Jens Axboe <axboe@kernel.dk>,
tomaz.solc@tablix.org, aaron.lu@intel.com,
linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: Writeback threads and freezable
Date: Wed, 18 Dec 2013 23:14:24 +0100 [thread overview]
Message-ID: <1639602.dY4DbMiF4F@vostro.rjw.lan> (raw)
In-Reply-To: <20131218114343.GA4324@htj.dyndns.org>
On Wednesday, December 18, 2013 06:43:43 AM Tejun Heo wrote:
[...]
> If filesystems need an indication that the underlying device is no
> longer functional, please go ahead and add it, but please keep in mind
> all these are completely asynchronous. Nothing guarantees you that
> such events would happen in any specific order. IOW, you can be at
> *ANY* point in your warm unplug path and the device is hot unplugged,
> which essentially forces all the code paths to be ready for the worst,
> and that's exactly why there isn't much effort in trying to separate
> out warm and hot unplug paths.
Yes. Devices can go away at any point without notice. Even PCI devices
that have never been assumed to be hot-removable. Any piece of code in the
kernel needs to be prepared to deal with such situations.
Thanks,
Rafael
next prev parent reply other threads:[~2013-12-18 22:01 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-13 17:49 Writeback threads and freezable Tejun Heo
2013-12-13 18:52 ` Tejun Heo
2013-12-13 20:40 ` [PATCH] libata, freezer: avoid block device removal while system is frozen Tejun Heo
2013-12-13 22:45 ` Nigel Cunningham
2013-12-13 23:07 ` Tejun Heo
2013-12-13 23:15 ` Nigel Cunningham
2013-12-14 1:55 ` Dave Chinner
2013-12-14 20:31 ` Tejun Heo
2013-12-14 20:36 ` Tejun Heo
2013-12-14 21:21 ` Nigel Cunningham
2013-12-17 2:35 ` Rafael J. Wysocki
2013-12-17 2:34 ` Rafael J. Wysocki
2013-12-17 12:34 ` Tejun Heo
2013-12-18 0:35 ` Rafael J. Wysocki
2013-12-18 11:17 ` Tejun Heo
2013-12-18 21:48 ` Rafael J. Wysocki
2013-12-18 21:39 ` Tejun Heo
2013-12-18 21:41 ` Tejun Heo
2013-12-18 22:04 ` Rafael J. Wysocki
2013-12-19 23:35 ` [PATCH wq/for-3.14 1/2] workqueue: update max_active clamping rules Tejun Heo
2013-12-20 1:26 ` Rafael J. Wysocki
2013-12-19 23:37 ` [PATCH wq/for-3.14 2/2] workqueue: implement @drain for workqueue_set_max_active() Tejun Heo
2013-12-20 1:31 ` Rafael J. Wysocki
2013-12-20 13:32 ` Tejun Heo
2013-12-20 13:56 ` Rafael J. Wysocki
2013-12-20 14:23 ` Tejun Heo
2013-12-16 12:12 ` [PATCH] libata, freezer: avoid block device removal while system is frozen Ming Lei
2013-12-16 12:45 ` Tejun Heo
2013-12-16 13:24 ` Ming Lei
2013-12-16 16:05 ` Tejun Heo
2013-12-17 2:38 ` Rafael J. Wysocki
2013-12-17 12:36 ` Tejun Heo
2013-12-18 0:23 ` Rafael J. Wysocki
2013-12-17 12:50 ` [PATCH v2] " Tejun Heo
2013-12-18 1:04 ` Rafael J. Wysocki
2013-12-18 11:08 ` Tejun Heo
2013-12-18 12:07 ` [PATCH v3] " Tejun Heo
2013-12-18 22:08 ` Rafael J. Wysocki
2013-12-19 17:24 ` Tejun Heo
2013-12-19 18:54 ` [PATCH v4] " Tejun Heo
2013-12-14 1:53 ` Writeback threads and freezable Dave Chinner
2013-12-14 17:30 ` Greg Kroah-Hartman
2013-12-14 20:23 ` Tejun Heo
2013-12-16 3:56 ` Dave Chinner
2013-12-16 12:51 ` Tejun Heo
2013-12-16 12:56 ` Tejun Heo
2013-12-18 0:35 ` Dave Chinner
2013-12-18 11:43 ` Tejun Heo
2013-12-18 22:14 ` Rafael J. Wysocki [this message]
2013-12-19 4:08 ` Dave Chinner
2013-12-19 16:24 ` Tejun Heo
2013-12-20 0:51 ` Dave Chinner
2013-12-20 14:51 ` Tejun Heo
2013-12-20 14:00 ` Rafael J. Wysocki
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