The quilt patch titled
Subject: mm/zswap: delay the initializaton of zswap until the first enablement
has been removed from the -mm tree. Its filename was
mm-zswap-delay-the-initializaton-of-zswap-until-the-first-enablement.patch
This patch was dropped because it had testing failures
------------------------------------------------------
From: Liu Shixin <liushixin2@xxxxxxxxxx>
Subject: mm/zswap: delay the initializaton of zswap until the first enablement
Date: Thu, 25 Aug 2022 22:20:36 +0800
In the initialization of zswap, about 18MB memory will be allocated for
zswap_pool in my machine. Since not all users use zswap, the memory may
be wasted. Save the memory for these users by delaying the initialization
of zswap to first enablement.
[akpm@xxxxxxxxxxxxxxxxxxxx: s/init_zswap/zswap_init/]
Link: https://lkml.kernel.org/r/20220825142037.3214152-3-liushixin2@xxxxxxxxxx
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zswap.c | 50 ++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 40 insertions(+), 10 deletions(-)
--- a/mm/zswap.c~mm-zswap-delay-the-initializaton-of-zswap-until-the-first-enablement
+++ 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 *,
@@ -220,6 +222,8 @@ static atomic_t zswap_pools_count = ATOM
/* init state */
static int 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;
@@ -273,13 +277,13 @@ static void zswap_update_total_size(void
**********************************/
static struct kmem_cache *zswap_entry_cache;
-static int __init zswap_entry_cache_create(void)
+static int zswap_entry_cache_create(void)
{
zswap_entry_cache = KMEM_CACHE(zswap_entry, 0);
return zswap_entry_cache == NULL;
}
-static void __init zswap_entry_cache_destroy(void)
+static void zswap_entry_cache_destroy(void)
{
kmem_cache_destroy(zswap_entry_cache);
}
@@ -664,7 +668,7 @@ 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;
@@ -782,11 +786,17 @@ static int __zswap_param_set(const char
if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool)
return 0;
- /* if this is load-time (pre-init) param setting,
+ /*
+ * if zswap has not been initialized,
* don't create a pool; that's done during init.
*/
- if (zswap_init_state == ZSWAP_UNINIT)
- return param_set_charp(s, kp);
+ mutex_lock(&zswap_init_lock);
+ if (zswap_init_state == ZSWAP_UNINIT) {
+ ret = param_set_charp(s, kp);
+ mutex_unlock(&zswap_init_lock);
+ return ret;
+ }
+ mutex_unlock(&zswap_init_lock);
if (!type) {
if (!zpool_has_pool(s)) {
@@ -876,6 +886,14 @@ static int zswap_zpool_param_set(const c
static int zswap_enabled_param_set(const char *val,
const struct kernel_param *kp)
{
+ if (system_state == SYSTEM_RUNNING) {
+ mutex_lock(&zswap_init_lock);
+ if (zswap_setup()) {
+ mutex_unlock(&zswap_init_lock);
+ return -ENODEV;
+ }
+ mutex_unlock(&zswap_init_lock);
+ }
if (zswap_init_state == ZSWAP_INIT_FAILED) {
pr_err("can't enable, initialization failed\n");
return -ENODEV;
@@ -1432,7 +1450,7 @@ 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;
@@ -1463,7 +1481,7 @@ 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;
}
@@ -1472,11 +1490,14 @@ 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;
+ if (zswap_init_state != ZSWAP_UNINIT)
+ return 0;
+
if (zswap_entry_cache_create()) {
pr_err("entry cache creation failed\n");
goto cache_fail;
@@ -1534,8 +1555,17 @@ cache_fail:
zswap_enabled = false;
return -ENOMEM;
}
+
+static int __init zswap_init(void)
+{
+ /* skip init if zswap is disabled when system startup */
+ 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
bootmem-remove-the-vmemmap-pages-from-kmemleak-in-put_page_bootmem.patch
mm-zswap-skip-confusing-print-info.patch
