From: NeilBrown <neilb@suse.de>
To: Ming Lei <tom.leiming@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
Linux PM list <linux-pm@vger.kernel.org>,
mark gross <markgross@thegnar.org>,
LKML <linux-kernel@vger.kernel.org>,
John Stultz <john.stultz@linaro.org>,
Alan Stern <stern@rowland.harvard.edu>
Subject: Re: [RFC][PATCH 0/2] PM / Sleep: Extended control of suspend/hibernate interfaces
Date: Tue, 1 Nov 2011 08:15:54 +1100 [thread overview]
Message-ID: <20111101081554.52ee5b38@notabene.brown> (raw)
In-Reply-To: <CACVXFVO_qNoy=AMs4RQOPsNq5dnTsc-=-f70Njf9Hv8eRkx=+Q@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1737 bytes --]
On Tue, 1 Nov 2011 03:55:50 +0800 Ming Lei <tom.leiming@gmail.com> wrote:
> Hi,
>
> On Fri, Oct 14, 2011 at 3:45 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
>
> > Second, to address the backup problem, we need to allow user space
> > processes other than the suspend/hibernate process itself to prevent the
> > system from being put into sleep states. A mechanism for that is introduced
> > by the second patch in the form of the /dev/sleepctl special device working
> > kind of like user space wakelocks on Android (although in a simplified
> > fashion).
>
> I also have another similar example: write(fd, buffer, 100*4096).
>
> Suppose only 80*4096 are copied into pages of the file, then someone
> run ' echo mem > /sys/power/state ' to trigger system sleep, so only
> partial writing is completed before system sleep and data inconsistence
> may be caused for the file on filesystem.
>
> But I am not sure if it is possible to happen in reality.
>
> thank,
I'm not sure if it is possible either, but even if it is it isn't a new
problem. A suspend is expected to leave all sorts of external things in
inconsistent states. The contents of memory implicitly records all these
inconsistencies and allows them to be resolved in the normal course of things
after resume.
If you lose power to memory during suspend then you can certainly expect
filesystems to be corrupted in exactly the same sort of way that they can be
corrupted by a crash. This has always been the case and I assume always will
(until we get main-memory that preserves state without power)
We want to block suspend during backups not to avoid corruption but simply to
allow the backups to complete promptly.
NeilBrown
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 828 bytes --]
next prev parent reply other threads:[~2011-10-31 21:15 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-13 19:45 [RFC][PATCH 0/2] PM / Sleep: Extended control of suspend/hibernate interfaces Rafael J. Wysocki
2011-10-13 19:49 ` [RFC][PATCH 1/2] PM / Sleep: Add mechanism to disable suspend and hibernation Rafael J. Wysocki
2011-10-13 19:50 ` [RFC][PATCH 2/2] PM / Sleep: Introduce cooperative suspend/hibernate mode Rafael J. Wysocki
2011-10-13 22:58 ` John Stultz
2011-10-14 22:49 ` Rafael J. Wysocki
2011-10-15 0:04 ` John Stultz
2011-10-15 21:29 ` Rafael J. Wysocki
2011-10-17 16:48 ` John Stultz
2011-10-17 18:19 ` Alan Stern
2011-10-17 19:08 ` John Stultz
2011-10-17 20:07 ` Alan Stern
2011-10-17 20:34 ` John Stultz
2011-10-17 20:38 ` Rafael J. Wysocki
2011-10-17 21:20 ` John Stultz
2011-10-17 21:19 ` NeilBrown
2011-10-17 21:43 ` John Stultz
2011-10-17 23:06 ` NeilBrown
2011-10-17 23:14 ` NeilBrown
2011-10-17 21:13 ` Rafael J. Wysocki
2011-10-14 5:52 ` [RFC][PATCH 0/2] PM / Sleep: Extended control of suspend/hibernate interfaces NeilBrown
2011-10-14 16:00 ` Alan Stern
2011-10-14 21:07 ` NeilBrown
2011-10-15 18:34 ` Alan Stern
2011-10-15 21:43 ` NeilBrown
2011-10-15 22:10 ` Rafael J. Wysocki
2011-10-16 2:49 ` Alan Stern
2011-10-16 14:51 ` Alan Stern
2011-10-16 20:32 ` Rafael J. Wysocki
2011-10-17 15:33 ` Alan Stern
2011-10-17 21:10 ` Rafael J. Wysocki
2011-10-17 21:27 ` Rafael J. Wysocki
2011-10-18 17:30 ` Alan Stern
2011-10-16 22:34 ` NeilBrown
2011-10-17 14:45 ` Alan Stern
2011-10-17 22:49 ` NeilBrown
2011-10-17 23:47 ` John Stultz
2011-10-18 2:13 ` NeilBrown
2011-10-18 17:11 ` Alan Stern
2011-10-18 22:55 ` NeilBrown
2011-10-19 16:19 ` Alan Stern
2011-10-20 0:17 ` NeilBrown
2011-10-20 14:29 ` Alan Stern
2011-10-21 5:05 ` NeilBrown
2011-10-21 5:23 ` lsusd - The Linux SUSpend Daemon NeilBrown
2011-10-21 16:07 ` Alan Stern
2011-10-21 22:34 ` NeilBrown
2011-10-22 2:00 ` Alan Stern
2011-10-22 16:31 ` Alan Stern
2011-10-23 3:31 ` NeilBrown
2011-10-23 8:21 ` NeilBrown
2011-10-23 12:48 ` Rafael J. Wysocki
2011-10-23 23:04 ` NeilBrown
2011-10-23 16:17 ` Alan Stern
2011-10-21 20:10 ` david
2011-10-21 22:09 ` NeilBrown
2011-10-26 14:31 ` Jan Engelhardt
2011-10-27 4:34 ` NeilBrown
2011-10-31 15:11 ` [RFC][PATCH 0/2] PM / Sleep: Extended control of suspend/hibernate interfaces Richard Hughes
2011-10-16 20:26 ` Rafael J. Wysocki
2011-10-16 23:48 ` NeilBrown
2011-10-17 15:43 ` Alan Stern
2011-10-17 22:02 ` Rafael J. Wysocki
2011-10-17 23:36 ` NeilBrown
2011-10-22 22:07 ` Rafael J. Wysocki
2011-10-23 2:57 ` NeilBrown
2011-10-23 13:16 ` Rafael J. Wysocki
2011-10-23 23:44 ` NeilBrown
2011-10-24 10:23 ` Rafael J. Wysocki
2011-10-25 2:52 ` NeilBrown
2011-10-25 7:47 ` Valdis.Kletnieks
2011-10-25 8:35 ` Rafael J. Wysocki
2011-10-23 15:50 ` Alan Stern
2011-10-27 21:06 ` Rafael J. Wysocki
2011-10-28 0:02 ` NeilBrown
2011-10-28 8:27 ` Rafael J. Wysocki
2011-10-28 15:08 ` Alan Stern
2011-10-28 17:26 ` Rafael J. Wysocki
2011-10-31 19:55 ` Ming Lei
2011-10-31 21:15 ` NeilBrown [this message]
2011-10-31 21:23 ` Ming Lei
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20111101081554.52ee5b38@notabene.brown \
--to=neilb@suse.de \
--cc=john.stultz@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=markgross@thegnar.org \
--cc=rjw@sisk.pl \
--cc=stern@rowland.harvard.edu \
--cc=tom.leiming@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.