On Sunday, May 15, 2011, Rafael J. Wysocki wrote: > On Sunday, May 15, 2011, Martin Steigerwald wrote: > > Am Sonntag, 15. Mai 2011 schrieb Rafael J. Wysocki: > > > Hi, > > > > Hi Rafael, > > Hi, > > > > On Tuesday, May 10, 2011, Rafael J. Wysocki wrote: > > > > 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. > > > > Extensively > > > > Tested-by: Martin Steigerwald <Martin@xxxxxxxxxxxx> > > > > This patch makes a complete difference for me. Instead of not knowing > > whether my ThinkPad T42 will hibernate with lots of applications open and > > thus closing applications prior to hibernation preventively now it simply > > will. *Always*. > > > > I even tested it with two KDE 4 sessions with running desktop search > > indexing on one. It took ages, cause KDE 4.6 desktop search / nepomuk stuff > > seems to I/O load the machine beyond anything (bugs reported there), but > > it worked. > > > > 16 MiB reserved_size has been enough for one KDE session. With 128 MiB the > > linux kernel hibernated two KDE sessions. > > > > Drivers allocating their memory via suspend/hibernate notifiers according > > to Rafael should fix the root cause, but until that is done, this will do. > > Adjusting imagesize instead never gave me such a reliable result. > > In fact, if drivers allocated their memory from suspend/hibernate notifiers, > that would be practically equivalent to setting reserved_size to the total > amount of memory reserved by the drivers. However, it may be difficult > for drivers to predict how much memory they will need at the time the > notifiers are called (they are called before freezing user space). > > Thus I'm considering a change that will cause device drivers' ->prepare() > callbacks to be executed before the preallocation of memory takes place. > In that case the drivers may allocate memory from their ->prepare() > callbacks _after_ user space has been frozen and that will make more > sense overall. > > For now, however, I think that exposing reserved_size is the right choice. BTW, I'm going to add the appended patch on top of it. Thanks, Rafael --- Author: Rafael J. Wysocki <rjw@xxxxxxx> Date: Sun May 15 11:39:48 2011 +0200 Revert "PM / Hibernate: Reduce autotuned default image size" This reverts commit bea3864fb627d110933cfb8babe048b63c4fc76e (PM / Hibernate: Reduce autotuned default image size), because users are now able to resolve the issue this commit was supposed to address in a different way (i.e. by using the new /sys/power/reserved_size interface). Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index d69e332..ace5588 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -54,15 +54,15 @@ void __init hibernate_reserved_size_init(void) /* * Preferred image size in bytes (tunable via /sys/power/image_size). - * When it is set to N, the image creating code will do its best to - * ensure the image size will not exceed N bytes, but if that is - * impossible, it will try to create the smallest image possible. + * When it is set to N, swsusp will do its best to ensure the image + * size will not exceed N bytes, but if that is impossible, it will + * try to create the smallest image possible. */ unsigned long image_size; void __init hibernate_image_size_init(void) { - image_size = (totalram_pages / 3) * PAGE_SIZE; + image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE; } /* List of PBEs needed for restoring the pages that were allocated before _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
