From ddeb648708108091a641adad0a438ec4fd8bf190 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 15 May 2011 11:38:48 +0200 Subject: PM / Hibernate: Add sysfs knob to control size of memory for drivers 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 hibernate 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-and-tested-by: Martin Steigerwald Signed-off-by: Rafael J. Wysocki --- kernel/power/power.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/power/power.h') diff --git a/kernel/power/power.h b/kernel/power/power.h index 03634be55f6..9a00a0a2628 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -15,6 +15,7 @@ struct swsusp_info { #ifdef CONFIG_HIBERNATION /* kernel/power/snapshot.c */ +extern void __init hibernate_reserved_size_init(void); extern void __init hibernate_image_size_init(void); #ifdef CONFIG_ARCH_HIBERNATION_HEADER @@ -55,6 +56,7 @@ extern int hibernation_platform_enter(void); #else /* !CONFIG_HIBERNATION */ +static inline void hibernate_reserved_size_init(void) {} static inline void hibernate_image_size_init(void) {} #endif /* !CONFIG_HIBERNATION */ @@ -72,6 +74,8 @@ static struct kobj_attribute _name##_attr = { \ /* Preferred image size in bytes (default 500 MB) */ extern unsigned long image_size; +/* Size of memory reserved for drivers (default SPARE_PAGES x PAGE_SIZE) */ +extern unsigned long reserved_size; extern int in_suspend; extern dev_t swsusp_resume_device; extern sector_t swsusp_resume_block; -- cgit v1.2.3-70-g09d2