Am Mittwoch, 18. Mai 2011 schrieb Pavel Machek: > Hi! > > > > From: Rafael J. Wysocki <rjw@xxxxxxx> > > > > > > Martin reports that on his system hibernation occasionally fails > > > due to the lack of memory, because the radeon driver apparently > > > allocates too much of it during the device freeze stage. It turns > > > out that the amount of memory allocated by radeon during > > > hibernation (and presumably during system suspend too) depends on > > > the utilization of the GPU (e.g. hibernating while there are two > > > KDE 4 sessions with compositing enabled causes radeon to allocate > > > more memory than for one KDE 4 session). > > > > > > In principle it should be possible to use image_size to make the > > > memory preallocation mechanism free enough memory for the radeon > > > driver, but in practice it is not easy to guess the right value > > > because of the way the preallocation code uses image_size. For > > > this reason, it seems reasonable to allow users to control the > > > amount of memory reserved for driver allocations made after the > > > preallocation, which currently is constant and amounts to 1 MB. > > > > > > Introduce a new sysfs file, /sys/power/reserved_size, whose value > > > will be used as the amount of memory to reserve for the > > > post-preallocation reservations made by device drivers, in bytes. > > > For backwards compatibility, set its default (and initial) value to > > > the currently used number (1 MB). > > > > > > References: https://bugzilla.kernel.org/show_bug.cgi?id=34102 > > > Reported-by: Martin Steigerwald <Martin@xxxxxxxxxxxx> > > > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> > > > > OK, there are no comments, so my understanding is that everyone is > > fine with this patch and I can add it to my linux-next branch. > > Actually no, I don't like it. Yes, knob might be useful for debugging, > but having it as part of official kernel interface... Well I and people with similar setups it is actually quite useful. It makes the difference between does hibernate *every time* versus does not hibernate sometimes. And I don't see why it can't go again, when the issue is taken care of elsewise in the future. I think that autotuning / drivers allocating their memory via whatnot is better, but until such a mechanism is agreed, developed and included in official kernel I do think that this knob does help. So or so I will patch this in for the kernels for my ThinkPad T42, whether its part of the official kernel or not. And I build my own kernels anyway. So when described issue really only happens on my setup and nowhere else... I think missing is some documentation so that the advanced user can figure out this knob. -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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