From: Jonas Meurer <jonas@freesources.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>, Pavel Machek <pavel@ucw.cz>,
Len Brown <len.brown@intel.com>,
Tim Dittler <tim.dittler@systemli.org>,
Yannik Sembritzki <yannik@sembritzki.me>
Subject: Re: [PATCH v3] PM: suspend: Add sysfs attribute to control the "sync on suspend" behavior
Date: Sun, 19 Jan 2020 13:55:58 +0100 [thread overview]
Message-ID: <a75f2426-21e3-06b0-9aa1-a4bc9d8368f3@freesources.org> (raw)
In-Reply-To: <CAJZ5v0gXMkL8Z_=jUvNGoVjDr4s5osO8RNekJ1yg-b+=zi7GSw@mail.gmail.com>
Hey Rafael,
Rafael J. Wysocki:
> On Thu, Jan 16, 2020 at 12:53 PM Jonas Meurer <jonas@freesources.org> wrote:
>>
>> The sysfs attribute `/sys/power/sync_on_suspend` controls, whether or not
>> filesystems are synced by the kernel before system suspend.
>>
>> Congruously, the behaviour of build-time switch CONFIG_SUSPEND_SKIP_SYNC
>> is slightly changed: It now defines the run-tim default for the new sysfs
>> attribute `/sys/power/sync_on_suspend`.
>>
>> The run-time attribute is added because the existing corresponding
>> build-time Kconfig flag for (`CONFIG_SUSPEND_SKIP_SYNC`) is not flexible
>> enough. E.g. Linux distributions that provide pre-compiled kernels
>> usually want to stick with the default (sync filesystems before suspend)
>> but under special conditions this needs to be changed.
>>
>> One example for such a special condition is user-space handling of
>> suspending block devices (e.g. using `cryptsetup luksSuspend` or `dmsetup
>> suspend`) before system suspend. The Kernel trying to sync filesystems
>> after the underlying block device already got suspended obviously leads
>> to dead-locks. Be aware that you have to take care of the filesystem sync
>> yourself before suspending the system in those scenarios.
>>
>> Signed-off-by: Jonas Meurer <jonas@freesources.org>
>
> Applied as 5.6 material with minor changes in the ABI document, thanks!
Wow, that's great news. I'm excited to read that the patch finally will
enter the Linux kernel \o/
Thanks a lot for guiding me through my first Linux kernel patch
contribution.
Cheers
jonas
next prev parent reply other threads:[~2020-01-19 12:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 11:53 [PATCH v3] PM: suspend: Add sysfs attribute to control the "sync on suspend" behavior Jonas Meurer
2020-01-16 20:49 ` Rafael J. Wysocki
2020-01-19 12:55 ` Jonas Meurer [this message]
2020-01-30 12:19 ` Pavel Machek
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