Messages in this thread | | | Date | Fri, 2 Dec 2011 20:30:37 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH] PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl error/test paths |
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> On 12/01/2011 09:17 PM, Tejun Heo wrote: > > > On Thu, Dec 01, 2011 at 06:45:37PM +0530, Srivatsa S. Bhat wrote: > >> Commit 2aede851ddf08666f68ffc17be446420e9d2a056 (PM / Hibernate: Freeze > >> kernel threads after preallocating memory) moved the freezing of kernel > >> threads to hibernation_snapshot() function. > >> > >> So now, if the call to hibernation_snapshot() fails or returns early due > >> to a successful hibernation test, the caller has to thaw processes to > >> ensure that the system gets back to its original state. > >> > >> But in SNAPSHOT_CREATE_IMAGE hibernation ioctl, the caller does not thaw > >> processes. Fix this issue. But note that if hibernation_snapshot() returned > >> due to a successful freezer test, we still send the value of 'in_suspend' > >> (which is now 0) to userspace, because we are not in an error path per-se, > >> and moreover, the value of in_suspend correctly depicts the situation here. > >> > >> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> > > > > Is this still applicable on top of pm-freezer branch? > > > > > Well, yes, but not in this form. Thanks for bringing that up! > > If the call to hibernation_snapshot() returns an error, we need not do > anything since your freezer changes handle that case and call thaw_processes() > automatically. > But in case of return due to a successful freezer test, we would need to > explicitly thaw processes since the freezer successfully froze them in the > previous step. > > So the following patch would do that, for the pm-freezer branch: > > --- > From: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> > Subject: [PATCH] PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl test path > > Commit 2aede851ddf08666f68ffc17be446420e9d2a056 (PM / Hibernate: Freeze > kernel threads after preallocating memory) moved the freezing of kernel > threads to hibernation_snapshot() function. > > So now, if the call to hibernation_snapshot() returns early due to a > successful hibernation test, the caller has to thaw processes to ensure > that the system gets back to its original state. > > But in SNAPSHOT_CREATE_IMAGE hibernation ioctl, the caller does not thaw > processes in case hibernation_snapshot() returned due to a successful > freezer test. Fix this issue. But note we still send the value of 'in_suspend' > (which is now 0) to userspace, because we are not in an error path per-se, > and moreover, the value of in_suspend correctly depicts the situation here. > > Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Ack.
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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