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PM: hibernate: add sysfs interface for hibernate_compression_threads

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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: Xueqin Luo <luoxueqin@kylinos.cn>
Link: https://patch.msgid.link/c68c62f97fabf32507b8794ad8c16cd22ee656ac.1761046167.git.luoxueqin@kylinos.cn
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Xueqin Luo
2025-10-21 19:37:28 +08:00
committed by Rafael J. Wysocki
parent 090bf5a0f4
commit ea358066de
2 changed files with 54 additions and 0 deletions
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16
Documentation/ABI/testing/sysfs-power
View File

@@ -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

38
kernel/power/swap.c
View File

@@ -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");