From 141fdeececb3d7b782ea7361a22659775d53bc2a Mon Sep 17 00:00:00 2001 From: Liu Shixin Date: Mon, 3 Apr 2023 20:13:18 +0800 Subject: [PATCH] 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.com Signed-off-by: Liu Shixin Reviewed-by: Christoph Hellwig Cc: Dan Streetman Cc: Nathan Chancellor Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton --- mm/zswap.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 54 insertions(+), 17 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index 9169c2b..af97e8f 100644 --- a/mm/zswap.c +++ b/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; @@ -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 @@ 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 "); -- 2.7.4