Commit ea358066 authored by Xueqin Luo's avatar Xueqin Luo Committed by Rafael J. Wysocki
Browse files

PM: hibernate: add sysfs interface for hibernate_compression_threads 



Add a sysfs attribute `/sys/power/hibernate_compression_threads` to
allow runtime configuration of the number of threads used for
compressing and decompressing hibernation images.

The new sysfs interface enables dynamic adjustment at runtime:

    # cat /sys/power/hibernate_compression_threads
    3
    # echo 4 > /sys/power/hibernate_compression_threads

This change provides greater flexibility for debugging and performance
tuning of hibernation without requiring a reboot.

Signed-off-by: default avatarXueqin Luo <luoxueqin@kylinos.cn>
Link: https://patch.msgid.link/c68c62f97fabf32507b8794ad8c16cd22ee656ac.1761046167.git.luoxueqin@kylinos.cn


Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 090bf5a0

Documentation/ABI/testing/sysfs-power

+16 −0
Original line number Diff line number Diff line
@@ -454,3 +454,19 @@ Description: 
		disables it.  Reads from the file return the current value.

		The default is "1" if the build-time "SUSPEND_SKIP_SYNC" config

		flag is unset, or "0" otherwise.



What:           /sys/power/hibernate_compression_threads

Date:           October 2025

Contact:        <luoxueqin@kylinos.cn>

Description:

                Controls the number of threads used for compression

                and decompression of hibernation images.



                The value can be adjusted at runtime to balance

                performance and CPU utilization.



                The change takes effect on the next hibernation or

                resume operation.



                Minimum value: 1

                Default value: 3

kernel/power/swap.c

+38 −0
Original line number Diff line number Diff line
@@ -1689,8 +1689,46 @@ int swsusp_unmark(void) 
}

#endif



static ssize_t hibernate_compression_threads_show(struct kobject *kobj,

				struct kobj_attribute *attr, char *buf)

{

	return sysfs_emit(buf, "%d\n", hibernate_compression_threads);

}



static ssize_t hibernate_compression_threads_store(struct kobject *kobj,

				struct kobj_attribute *attr,

				const char *buf, size_t n)

{

	unsigned long val;



	if (kstrtoul(buf, 0, &val))

		return -EINVAL;



	if (val < 1)

		return -EINVAL;



	hibernate_compression_threads = val;

	return n;

}

power_attr(hibernate_compression_threads);



static struct attribute *g[] = {

	&hibernate_compression_threads_attr.attr,

	NULL,

};



static const struct attribute_group attr_group = {

	.attrs = g,

};



static int __init swsusp_header_init(void)

{

	int error;



	error = sysfs_create_group(power_kobj, &attr_group);

	if (error)

		return -ENOMEM;



	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);

	if (!swsusp_header)

		panic("Could not allocate memory for swsusp_header\n");