Commit 141fdeec authored by Liu Shixin's avatar Liu Shixin Committed by Andrew Morton

mm/zswap: delay the initialization of zswap

Since some users may not use zswap, the zswap_pool is wasted.  Save memory
by delaying the initialization of zswap until enabled.

[liushixin2@huawei.com: fix some pattern problem suggested by Christoph]
  Link: https://lkml.kernel.org/r/20230411093632.822290-4-liushixin2@huawei.com
Link: https://lkml.kernel.org/r/20230403121318.1876082-4-liushixin2@huawei.comSigned-off-by: default avatarLiu Shixin <liushixin2@huawei.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9021ccec
......@@ -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 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
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;
......@@ -755,29 +760,43 @@ static void zswap_pool_put(struct zswap_pool *pool)
* param callbacks
**********************************/
static bool zswap_pool_changed(const char *s, const struct kernel_param *kp)
{
/* no change required */
if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool)
return false;
return true;
}
/* val must be a null-terminated string */
static int __zswap_param_set(const char *val, const struct kernel_param *kp,
char *type, char *compressor)
{
struct zswap_pool *pool, *put_pool = NULL;
char *s = strstrip((char *)val);
int ret;
int ret = 0;
bool new_pool = false;
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);
break;
case ZSWAP_INIT_SUCCEED:
/* no change required */
if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool)
return 0;
new_pool = zswap_pool_changed(s, kp);
break;
case ZSWAP_INIT_FAILED:
pr_err("can't set param, initialization failed\n");
return -ENODEV;
ret = -ENODEV;
}
mutex_unlock(&zswap_init_lock);
/* no need to create a new pool, return directly */
if (!new_pool)
return ret;
if (!type) {
if (!zpool_has_pool(s)) {
......@@ -867,19 +886,30 @@ static int zswap_zpool_param_set(const char *val,
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 +1467,7 @@ static const struct frontswap_ops zswap_frontswap_ops = {
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 +1498,7 @@ static int __init zswap_debugfs_init(void)
return 0;
}
#else
static int __init zswap_debugfs_init(void)
static int zswap_debugfs_init(void)
{
return 0;
}
......@@ -1477,7 +1507,7 @@ static int __init zswap_debugfs_init(void)
/*********************************
* module init and exit
**********************************/
static int __init init_zswap(void)
static int zswap_setup(void)
{
struct zswap_pool *pool;
int ret;
......@@ -1540,8 +1570,15 @@ static int __init init_zswap(void)
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@variantweb.net>");
......
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