Re: [linux-pm] [PATCH 1/4] freezer: make fake_signal_wake_up wakeTASK_KILLABLE tasks too

[Steve French]

FYI - I included the cifs one "cifs, freezer: add
wait_event_freezekillable and have cifs use it" (and the corequisite
fix for the build break when freezer not enabled) in my recent cifs
merge request.

On Thu, Oct 27, 2011 at 3:22 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> On Thursday, October 27, 2011, Rafael J. Wysocki wrote:
>> On Wednesday, October 26, 2011, Jeff Layton wrote:
>> > On Tue, 11 Oct 2011 21:14:28 +0200
>> > "Rafael J. Wysocki" <rjw@xxxxxxx> wrote:
>> >
>> > > On Tuesday, October 11, 2011, Jeff Layton wrote:
>> > > > On Tue, 11 Oct 2011 08:18:48 +0200
>> > > > Pavel Machek <pavel@xxxxxx> wrote:
>> > > >
>> > > > >
>> > > > > Hi!
>> > > > >
>> > > > > > TASK_KILLABLE is often used to put tasks to sleep for quite some time.
>> > > > > > One of the most common uses is to put tasks to sleep while waiting for
>> > > > > > replies from a server on a networked filesystem (such as CIFS or NFS).
>> > > > > >
>> > > > > > Unfortunately, fake_signal_wake_up does not currently wake up tasks
>> > > > > > that are sleeping in TASK_KILLABLE state. This means that even if the
>> > > > > > code were in place to allow them to freeze while in this sleep, it
>> > > > > > wouldn't work anyway.
>> > > > > >
>> > > > > > This patch changes this function to wake tasks in this state as well.
>> > > > > > This should be harmless -- if the code doing the sleeping doesn't have
>> > > > > > handling to deal with freezer events, it should just go back to sleep.
>> > > > >
>> > > > > I'm pretty sure this will break something; but that does not mean it
>> > > > > is bad idea, just that it should be merged early and tested a lot.
>> > > > >
>> > > >
>> > > > FWIW, I looked at most of the places in the kernel that do
>> > > > TASK_KILLABLE sleeps and they look like they'll handle this correctly.
>> > > > The main one I wasn't sure about was mem_cgroup_handle_oom(), but I
>> > > > think it'll do the right thing too. I certainly could have missed
>> > > > something though...
>> > > >
>> > > > In any case, would you mind merging this via the linux-pm tree for 3.2?
>> > >
>> > > I will push it for 3.2.
>> > >
>> >
>> > Hi Rafael,
>> >
>> > Trond asked if you would also be willing to push patches 3 and 4 in
>> > this series for 3.2 as well [1]? Note that patch #4 got another revision so
>> > we'll want to make sure that you get that one. I can resend the
>> > nfs/sunrpc patches if that will help...
>> >
>> > [1]: I think Steve F is going to push patch #2, so that one shouldn't
>> > be an issue.
>>
>> Well, I've already sent my pull request.  I can keep these patches in my
>> tree for the next pull request, though (I'm sure there will be fixes against
>> 3.2, so they will go along with those).
>
> BTW, do you have current versions handy?  Or hasn't they changed?
>
> Rafael
>



-- 
Thanks,

Steve
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