diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0750-zswap-Defer-zswap-initialisation.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0750-zswap-Defer-zswap-initialisation.patch | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0750-zswap-Defer-zswap-initialisation.patch b/target/linux/bcm27xx/patches-5.4/950-0750-zswap-Defer-zswap-initialisation.patch new file mode 100644 index 0000000000..124a1d95cd --- /dev/null +++ b/target/linux/bcm27xx/patches-5.4/950-0750-zswap-Defer-zswap-initialisation.patch @@ -0,0 +1,115 @@ +From 66e0ea531f4975fed5899a2cbbfa3986fca40680 Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.com> +Date: Tue, 5 May 2020 15:23:32 +0100 +Subject: [PATCH] zswap: Defer zswap initialisation + +Enabling zswap support in the kernel configuration costs about 1.5MB +of RAM, even when zswap is not enabled at runtime. This cost can be +reduced significantly by deferring initialisation (including pool +creation) until the "enabled" parameter is set to true. There is a +small cost to this in that some initialisation code has to remain in +memory after the init phase, just in case they are needed later, +but the total size increase is negligible. + +See: https://github.com/raspberrypi/linux/pull/3432 + +Signed-off-by: Phil Elwell <phil@raspberrypi.com> +--- + mm/zswap.c | 48 ++++++++++++++++++++++++++++-------------------- + 1 file changed, 28 insertions(+), 20 deletions(-) + +--- a/mm/zswap.c ++++ b/mm/zswap.c +@@ -564,8 +564,9 @@ error: + return NULL; + } + +-static __init struct zswap_pool *__zswap_pool_create_fallback(void) ++static bool zswap_try_pool_create(void) + { ++ struct zswap_pool *pool; + bool has_comp, has_zpool; + + has_comp = crypto_has_comp(zswap_compressor, 0, 0); +@@ -599,9 +600,21 @@ static __init struct zswap_pool *__zswap + } + + if (!has_comp || !has_zpool) +- return NULL; ++ return false; ++ ++ pool = zswap_pool_create(zswap_zpool_type, zswap_compressor); ++ ++ if (pool) { ++ pr_info("loaded using pool %s/%s\n", pool->tfm_name, ++ zpool_get_type(pool->zpool)); ++ list_add(&pool->list, &zswap_pools); ++ zswap_has_pool = true; ++ } else { ++ pr_err("pool creation failed\n"); ++ zswap_enabled = false; ++ } + +- return zswap_pool_create(zswap_zpool_type, zswap_compressor); ++ return zswap_enabled; + } + + static void zswap_pool_destroy(struct zswap_pool *pool) +@@ -773,16 +786,19 @@ static int zswap_zpool_param_set(const c + static int zswap_enabled_param_set(const char *val, + const struct kernel_param *kp) + { ++ int ret; ++ + if (zswap_init_failed) { + pr_err("can't enable, initialization failed\n"); + return -ENODEV; + } +- if (!zswap_has_pool && zswap_init_started) { +- pr_err("can't enable, no pool configured\n"); +- return -ENODEV; +- } + +- return param_set_bool(val, kp); ++ ret = param_set_bool(val, kp); ++ if (!ret && zswap_enabled && zswap_init_started && !zswap_has_pool) ++ if (!zswap_try_pool_create()) ++ ret = -ENODEV; ++ ++ return ret; + } + + /********************************* +@@ -1297,7 +1313,6 @@ static void __exit zswap_debugfs_exit(vo + **********************************/ + static int __init init_zswap(void) + { +- struct zswap_pool *pool; + int ret; + + zswap_init_started = true; +@@ -1321,20 +1336,13 @@ static int __init init_zswap(void) + if (ret) + goto hp_fail; + +- pool = __zswap_pool_create_fallback(); +- if (pool) { +- pr_info("loaded using pool %s/%s\n", pool->tfm_name, +- zpool_get_type(pool->zpool)); +- list_add(&pool->list, &zswap_pools); +- zswap_has_pool = true; +- } else { +- pr_err("pool creation failed\n"); +- zswap_enabled = false; +- } +- + frontswap_register_ops(&zswap_frontswap_ops); + if (zswap_debugfs_init()) + pr_warn("debugfs initialization failed\n"); ++ ++ if (zswap_enabled) ++ zswap_try_pool_create(); ++ + return 0; + + hp_fail: |