Currently the default compression algorithm is selected based on
compile time options. Introduce a module parameter "hibernate.compressor"
to override this behaviour.
Different compression algorithms have different characteristics and
hibernation may benefit when it uses any of these algorithms, especially
when a secondary algorithm(LZ4) offers better decompression speeds over a
default algorithm(LZO), which in turn reduces hibernation image restore
time.
Users can override the default algorithm in two ways:
1) Passing "hibernate.compressor" as kernel command line parameter.
Usage:
LZO: hibernate.compressor=lzo
LZ4: hibernate.compressor=lz4
2) Specifying the algorithm at runtime.
Usage:
LZO: echo lzo > /sys/module/hibernate/parameters/compressor
LZ4: echo lz4 > /sys/module/hibernate/parameters/compressor
Currently LZO and LZ4 are the supported algorithms. LZO is the default
compression algorithm used with hibernation.
Signed-off-by: Nikhil V <quic_nprakash@xxxxxxxxxxx>
---
This patch is dependent on the patch series, [1] (patches 1/4 to 3/4).
This is picked in linux-next, [2].
[1] https://lore.kernel.org/all/cover.1705927916.git.quic_nprakash@xxxxxxxxxxx/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/kernel/power?h=next-20240212
Changes in v2:
Changes to incorporate suggestions from Randy Dunlap:
- Update documentation to specify the default compression algorithm.
Link to v1:
https://lore.kernel.org/all/3776355f920c1af44490e076072f93bafdf128cc.1707740870.git.quic_nprakash@xxxxxxxxxxx/
.../admin-guide/kernel-parameters.txt | 11 ++++
kernel/power/hibernate.c | 57 ++++++++++++++++++-
2 files changed, 65 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 31b3a25680d0..8f7fb911b2cc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1748,6 +1748,17 @@
(that will set all pages holding image data
during restoration read-only).
+ hibernate.compressor= [HIBERNATION] Compression algorithm to be
+ used with hibernation.
+ Format: { lzo | lz4 }
+ Default: lzo
+
+ lzo: Select LZO compression algorithm to
+ compress/decompress hibernation image.
+
+ lz4: Select LZ4 compression algorithm to
+ compress/decompress hibernation image.
+
highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
size of <nn>. This works even on boxes that have no
highmem otherwise. This also works to reduce highmem
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 219191d6d0e8..43b1a82e800c 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -47,7 +47,7 @@ dev_t swsusp_resume_device;
sector_t swsusp_resume_block;
__visible int in_suspend __nosavedata;
-static const char *default_compressor = CONFIG_HIBERNATION_DEF_COMP;
+static char hibernate_compressor[CRYPTO_MAX_ALG_NAME] = CONFIG_HIBERNATION_DEF_COMP;
/*
* Compression/decompression algorithm to be used while saving/loading
@@ -748,7 +748,7 @@ int hibernate(void)
* Query for the compression algorithm support if compression is enabled.
*/
if (!nocompress) {
- strscpy(hib_comp_algo, default_compressor, sizeof(hib_comp_algo));
+ strscpy(hib_comp_algo, hibernate_compressor, sizeof(hib_comp_algo));
if (crypto_has_comp(hib_comp_algo, 0, 0) != 1) {
pr_err("%s compression is not available\n", hib_comp_algo);
return -EOPNOTSUPP;
@@ -999,7 +999,7 @@ static int software_resume(void)
if (swsusp_header_flags & SF_COMPRESSION_ALG_LZ4)
strscpy(hib_comp_algo, COMPRESSION_ALGO_LZ4, sizeof(hib_comp_algo));
else
- strscpy(hib_comp_algo, default_compressor, sizeof(hib_comp_algo));
+ strscpy(hib_comp_algo, COMPRESSION_ALGO_LZO, sizeof(hib_comp_algo));
if (crypto_has_comp(hib_comp_algo, 0, 0) != 1) {
pr_err("%s compression is not available\n", hib_comp_algo);
error = -EOPNOTSUPP;
@@ -1422,6 +1422,57 @@ static int __init nohibernate_setup(char *str)
return 1;
}
+static const char * const comp_alg_enabled[] = {
+#if IS_ENABLED(CONFIG_CRYPTO_LZO)
+ COMPRESSION_ALGO_LZO,
+#endif
+#if IS_ENABLED(CONFIG_CRYPTO_LZ4)
+ COMPRESSION_ALGO_LZ4,
+#endif
+};
+
+static int hibernate_compressor_param_set(const char *compressor,
+ const struct kernel_param *kp)
+{
+ unsigned int sleep_flags;
+ int index, ret;
+
+ sleep_flags = lock_system_sleep();
+
+ index = sysfs_match_string(comp_alg_enabled, compressor);
+ if (index >= 0) {
+ ret = param_set_copystring(comp_alg_enabled[index], kp);
+ if (!ret)
+ strscpy(hib_comp_algo, comp_alg_enabled[index],
+ sizeof(hib_comp_algo));
+ } else {
+ ret = index;
+ }
+
+ unlock_system_sleep(sleep_flags);
+
+ if (ret)
+ pr_debug("Cannot set specified compressor %s\n",
+ compressor);
+
+ return ret;
+}
+
+static const struct kernel_param_ops hibernate_compressor_param_ops = {
+ .set = hibernate_compressor_param_set,
+ .get = param_get_string,
+};
+
+static struct kparam_string hibernate_compressor_param_string = {
+ .maxlen = sizeof(hibernate_compressor),
+ .string = hibernate_compressor,
+};
+
+module_param_cb(compressor, &hibernate_compressor_param_ops,
+ &hibernate_compressor_param_string, 0644);
+MODULE_PARM_DESC(compressor,
+ "Compression algorithm to be used with hibernation");
+
__setup("noresume", noresume_setup);
__setup("resume_offset=", resume_offset_setup);
__setup("resume=", resume_setup);
--
2.17.1
