The patch titled
Subject: mm/zswap: delay the initialization of zswap
has been added to the -mm mm-unstable branch. Its filename is
mm-zswap-delay-the-initialization-of-zswap.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-delay-the-initialization-of-zswap.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Liu Shixin <liushixin2@xxxxxxxxxx>
Subject: mm/zswap: delay the initialization of zswap
Date: Mon, 3 Apr 2023 20:13:18 +0800
Since some users may not use zswap, the zswap_pool is wasted. Save memory
by delaying the initialization of zswap until enabled.
Link: https://lkml.kernel.org/r/20230403121318.1876082-4-liushixin2@xxxxxxxxxx
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zswap.c | 56 +++++++++++++++++++++++++++++++++++++++------------
1 file changed, 43 insertions(+), 13 deletions(-)
--- a/mm/zswap.c~mm-zswap-delay-the-initialization-of-zswap
+++ a/mm/zswap.c
@@ -81,6 +81,8 @@ static bool zswap_pool_reached_full;
#define ZSWAP_PARAM_UNSET ""
+static int zswap_setup(void);
+
/* Enable/disable zswap */
static bool zswap_enabled = IS_ENABLED(CONFIG_ZSWAP_DEFAULT_ON);
static int zswap_enabled_param_set(const char *,
@@ -222,6 +224,9 @@ enum zswap_init_type {
static enum zswap_init_type zswap_init_state;
+/* used to ensure the integrity of initialization */
+static DEFINE_MUTEX(zswap_init_lock);
+
/* init completed, but couldn't create the initial pool */
static bool zswap_has_pool;
@@ -654,7 +659,7 @@ error:
return NULL;
}
-static __init struct zswap_pool *__zswap_pool_create_fallback(void)
+static struct zswap_pool *__zswap_pool_create_fallback(void)
{
bool has_comp, has_zpool;
@@ -763,21 +768,28 @@ static int __zswap_param_set(const char
char *s = strstrip((char *)val);
int ret;
+ mutex_lock(&zswap_init_lock);
switch (zswap_init_state) {
case ZSWAP_UNINIT:
/* if this is load-time (pre-init) param setting,
* don't create a pool; that's done during init.
*/
- return param_set_charp(s, kp);
+ ret = param_set_charp(s, kp);
+ mutex_unlock(&zswap_init_lock);
+ return ret;
case ZSWAP_INIT_SUCCEED:
/* no change required */
- if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool)
+ if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool) {
+ mutex_unlock(&zswap_init_lock);
return 0;
+ }
break;
case ZSWAP_INIT_FAILED:
pr_err("can't set param, initialization failed\n");
+ mutex_unlock(&zswap_init_lock);
return -ENODEV;
}
+ mutex_unlock(&zswap_init_lock);
if (!type) {
if (!zpool_has_pool(s)) {
@@ -867,19 +879,30 @@ static int zswap_zpool_param_set(const c
static int zswap_enabled_param_set(const char *val,
const struct kernel_param *kp)
{
+ int ret = -ENODEV;
+
+ /*if this is load-time (pre-init) param setting, only set param.*/
+ if (system_state != SYSTEM_RUNNING)
+ return param_set_bool(val, kp);
+
+ mutex_lock(&zswap_init_lock);
switch (zswap_init_state) {
case ZSWAP_UNINIT:
- return param_set_bool(val, kp);
+ if (zswap_setup())
+ break;
+ fallthrough;
case ZSWAP_INIT_SUCCEED:
- if (!zswap_has_pool) {
+ if (!zswap_has_pool)
pr_err("can't enable, no pool configured\n");
- return -ENODEV;
- } else
- return param_set_bool(val, kp);
+ else
+ ret = param_set_bool(val, kp);
+ break;
case ZSWAP_INIT_FAILED:
pr_err("can't enable, initialization failed\n");
- return -ENODEV;
}
+ mutex_unlock(&zswap_init_lock);
+
+ return ret;
}
/*********************************
@@ -1437,7 +1460,7 @@ static const struct frontswap_ops zswap_
static struct dentry *zswap_debugfs_root;
-static int __init zswap_debugfs_init(void)
+static int zswap_debugfs_init(void)
{
if (!debugfs_initialized())
return -ENODEV;
@@ -1468,7 +1491,7 @@ static int __init zswap_debugfs_init(voi
return 0;
}
#else
-static int __init zswap_debugfs_init(void)
+static int zswap_debugfs_init(void)
{
return 0;
}
@@ -1477,7 +1500,7 @@ static int __init zswap_debugfs_init(voi
/*********************************
* module init and exit
**********************************/
-static int __init init_zswap(void)
+static int zswap_setup(void)
{
struct zswap_pool *pool;
int ret;
@@ -1540,8 +1563,15 @@ cache_fail:
zswap_enabled = false;
return -ENOMEM;
}
+
+static int __init zswap_init(void)
+{
+ if (!zswap_enabled)
+ return 0;
+ return zswap_setup();
+}
/* must be late so crypto has time to come up */
-late_initcall(init_zswap);
+late_initcall(zswap_init);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Seth Jennings <sjennings@xxxxxxxxxxxxxx>");
_
Patches currently in -mm which might be from liushixin2@xxxxxxxxxx are
mm-zswap-remove-zswap_entry_cache_createdestroy-helper-function.patch
mm-zswap-replace-zswap_init_started-failed-with-zswap_init_state.patch
mm-zswap-delay-the-initialization-of-zswap.patch
