From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2ADFC2EF for ; Sat, 30 Aug 2025 03:28:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756524530; cv=none; b=KKX8C3mIqDvZTUT+Zc0t1EcbwPpIazIqFx/IXk1bWip5NGGVulNEMgzyXZ5q+nyaZbdHONyjOTrEmscaX7IBBtmifN+EhC2y1CoC/GFmXP9RldAkQTOUnygrODjTf7IShOVVqmEkH3p9wR8cnYS19J8MyEmj8SZ5WyFdKtlNzPU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756524530; c=relaxed/simple; bh=5iChPSnlDMr1tsgagRu/6KQuB5+nRqlQQyMNnfqmDNU=; h=Date:To:From:Subject:Message-Id; b=fXN7A42AnSkjhLyRRHgooC0s1/6rH4l0K3TgyAgVdF6BDeqbbENxljf+WnJb4negP73ECHnibuSrcjGbZzYmCIF7YWptzW28WIkpoFgN7CRdsprGKVXOSmXVRcEr/2Znf91Ef6VIyXfc4de7/7SJghh14gqGd9mEC59ITUW/WLE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=HiVLnsLb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="HiVLnsLb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C37FC4CEF0; Sat, 30 Aug 2025 03:28:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1756524529; bh=5iChPSnlDMr1tsgagRu/6KQuB5+nRqlQQyMNnfqmDNU=; h=Date:To:From:Subject:From; b=HiVLnsLb9R6yjrSzYCxU4RL0av8EAUQtkMldSRBCMPI2ay9TZoK9/s6jQqMMR53yP tMLL8f7YWsHoEbHa6xrlwkt4kjXLT2pTxy7Z8Lg+sGT/ZJ34jRBKApI4UMTAUoK8Uf 3GZ+O1bEFWqilRdTE0bbq9ocbLU4aizY4sGtnFj4= Date: Fri, 29 Aug 2025 20:28:48 -0700 To: mm-commits@vger.kernel.org,zhouchengming@bytedance.com,yosryahmed@google.com,sj@kernel.org,nphamcs@gmail.com,hannes@cmpxchg.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-zswap-interact-directly-with-zsmalloc.patch added to mm-new branch Message-Id: <20250830032849.3C37FC4CEF0@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: zswap: interact directly with zsmalloc has been added to the -mm mm-new branch. Its filename is mm-zswap-interact-directly-with-zsmalloc.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-interact-directly-with-zsmalloc.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Johannes Weiner Subject: mm: zswap: interact directly with zsmalloc Date: Fri, 29 Aug 2025 17:15:26 +0100 Patch series "mm: remove zpool". zpool is an indirection layer for zswap to switch between multiple allocator backends at runtime. Since 6.15, zsmalloc is the only allocator left in-tree, so there is no point in keeping zpool around. This patch (of 3): zswap goes through the zpool layer to enable runtime-switching of allocator backends for compressed data. However, since zbud and z3fold were removed in 6.15, zsmalloc has been the only option available. As such, the zpool indirection is unnecessary. Make zswap deal with zsmalloc directly. This is comparable to zram, which also directly interacts with zsmalloc and has never supported a different backend. Note that this does not preclude future improvements and experiments with different allocation strategies. Should it become necessary, it's possible to provide an alternate implementation for the zsmalloc API, selectable at compile time. However, zsmalloc is also rather mature and feature rich, with years of widespread production exposure; it's encouraged to make incremental improvements rather than fork it. In any case, the complexity of runtime pluggability seems excessive and unjustified at this time. Switch zswap to zsmalloc to remove the last user of the zpool API. Link: https://lkml.kernel.org/r/20250829162212.208258-1-hannes@cmpxchg.org Link: https://lkml.kernel.org/r/20250829162212.208258-2-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Cc: Chengming Zhou Cc: Nhat Pham Cc: Yosry Ahmed Cc: SeongJae Park Signed-off-by: Andrew Morton --- mm/zswap.c | 202 +++++++++++++-------------------------------------- 1 file changed, 54 insertions(+), 148 deletions(-) --- a/mm/zswap.c~mm-zswap-interact-directly-with-zsmalloc +++ a/mm/zswap.c @@ -25,7 +25,6 @@ #include #include #include -#include #include #include #include @@ -35,6 +34,7 @@ #include #include #include +#include #include "swap.h" #include "internal.h" @@ -107,16 +107,6 @@ static const struct kernel_param_ops zsw module_param_cb(compressor, &zswap_compressor_param_ops, &zswap_compressor, 0644); -/* Compressed storage zpool to use */ -static char *zswap_zpool_type = CONFIG_ZSWAP_ZPOOL_DEFAULT; -static int zswap_zpool_param_set(const char *, const struct kernel_param *); -static const struct kernel_param_ops zswap_zpool_param_ops = { - .set = zswap_zpool_param_set, - .get = param_get_charp, - .free = param_free_charp, -}; -module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644); - /* The maximum percentage of memory that the compressed pool can occupy */ static unsigned int zswap_max_pool_percent = 20; module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644); @@ -161,7 +151,7 @@ struct crypto_acomp_ctx { * needs to be verified that it's still valid in the tree. */ struct zswap_pool { - struct zpool *zpool; + struct zs_pool *zs_pool; struct crypto_acomp_ctx __percpu *acomp_ctx; struct percpu_ref ref; struct list_head list; @@ -193,7 +183,7 @@ static struct shrinker *zswap_shrinker; * logic if referenced is unset. See comments in the shrinker * section for context. * pool - the zswap_pool the entry's data is in - * handle - zpool allocation handle that stores the compressed page data + * handle - zsmalloc allocation handle that stores the compressed page data * objcg - the obj_cgroup that the compressed memory is charged to * lru - handle to the pool's lru used to evict pages. */ @@ -214,7 +204,7 @@ static unsigned int nr_zswap_trees[MAX_S static LIST_HEAD(zswap_pools); /* protects zswap_pools list modification */ static DEFINE_SPINLOCK(zswap_pools_lock); -/* pool counter to provide unique names to zpool */ +/* pool counter to provide unique names to zsmalloc */ static atomic_t zswap_pools_count = ATOMIC_INIT(0); enum zswap_init_type { @@ -241,32 +231,22 @@ static inline struct xarray *swap_zswap_ >> SWAP_ADDRESS_SPACE_SHIFT]; } -#define zswap_pool_debug(msg, p) \ - pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \ - zpool_get_type((p)->zpool)) +#define zswap_pool_debug(msg, p) \ + pr_debug("%s pool %s\n", msg, (p)->tfm_name) /********************************* * pool functions **********************************/ static void __zswap_pool_empty(struct percpu_ref *ref); -static struct zswap_pool *zswap_pool_create(char *type, char *compressor) +static struct zswap_pool *zswap_pool_create(char *compressor) { struct zswap_pool *pool; char name[38]; /* 'zswap' + 32 char (max) num + \0 */ - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; int ret, cpu; - if (!zswap_has_pool) { - /* if either are unset, pool initialization failed, and we - * need both params to be set correctly before trying to - * create a pool. - */ - if (!strcmp(type, ZSWAP_PARAM_UNSET)) - return NULL; - if (!strcmp(compressor, ZSWAP_PARAM_UNSET)) - return NULL; - } + if (!zswap_has_pool && !strcmp(compressor, ZSWAP_PARAM_UNSET)) + return NULL; pool = kzalloc(sizeof(*pool), GFP_KERNEL); if (!pool) @@ -274,12 +254,9 @@ static struct zswap_pool *zswap_pool_cre /* unique name for each pool specifically required by zsmalloc */ snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count)); - pool->zpool = zpool_create_pool(type, name, gfp); - if (!pool->zpool) { - pr_err("%s zpool not available\n", type); + pool->zs_pool = zs_create_pool(name); + if (!pool->zs_pool) goto error; - } - pr_debug("using %s zpool\n", zpool_get_type(pool->zpool)); strscpy(pool->tfm_name, compressor, sizeof(pool->tfm_name)); @@ -315,52 +292,29 @@ ref_fail: error: if (pool->acomp_ctx) free_percpu(pool->acomp_ctx); - if (pool->zpool) - zpool_destroy_pool(pool->zpool); + if (pool->zs_pool) + zs_destroy_pool(pool->zs_pool); kfree(pool); return NULL; } static struct zswap_pool *__zswap_pool_create_fallback(void) { - bool has_comp, has_zpool; - - has_comp = crypto_has_acomp(zswap_compressor, 0, 0); - if (!has_comp && strcmp(zswap_compressor, - CONFIG_ZSWAP_COMPRESSOR_DEFAULT)) { + if (!crypto_has_acomp(zswap_compressor, 0, 0) && + strcmp(zswap_compressor, CONFIG_ZSWAP_COMPRESSOR_DEFAULT)) { pr_err("compressor %s not available, using default %s\n", zswap_compressor, CONFIG_ZSWAP_COMPRESSOR_DEFAULT); param_free_charp(&zswap_compressor); zswap_compressor = CONFIG_ZSWAP_COMPRESSOR_DEFAULT; - has_comp = crypto_has_acomp(zswap_compressor, 0, 0); - } - if (!has_comp) { - pr_err("default compressor %s not available\n", - zswap_compressor); - param_free_charp(&zswap_compressor); - zswap_compressor = ZSWAP_PARAM_UNSET; - } - - has_zpool = zpool_has_pool(zswap_zpool_type); - if (!has_zpool && strcmp(zswap_zpool_type, - CONFIG_ZSWAP_ZPOOL_DEFAULT)) { - pr_err("zpool %s not available, using default %s\n", - zswap_zpool_type, CONFIG_ZSWAP_ZPOOL_DEFAULT); - param_free_charp(&zswap_zpool_type); - zswap_zpool_type = CONFIG_ZSWAP_ZPOOL_DEFAULT; - has_zpool = zpool_has_pool(zswap_zpool_type); - } - if (!has_zpool) { - pr_err("default zpool %s not available\n", - zswap_zpool_type); - param_free_charp(&zswap_zpool_type); - zswap_zpool_type = ZSWAP_PARAM_UNSET; + if (!crypto_has_acomp(zswap_compressor, 0, 0)) { + pr_err("default compressor %s not available\n", + zswap_compressor); + zswap_compressor = ZSWAP_PARAM_UNSET; + return NULL; + } } - if (!has_comp || !has_zpool) - return NULL; - - return zswap_pool_create(zswap_zpool_type, zswap_compressor); + return zswap_pool_create(zswap_compressor); } static void zswap_pool_destroy(struct zswap_pool *pool) @@ -370,7 +324,7 @@ static void zswap_pool_destroy(struct zs cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node); free_percpu(pool->acomp_ctx); - zpool_destroy_pool(pool->zpool); + zs_destroy_pool(pool->zs_pool); kfree(pool); } @@ -462,7 +416,7 @@ static struct zswap_pool *zswap_pool_cur } /* type and compressor must be null-terminated */ -static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor) +static struct zswap_pool *zswap_pool_find_get(char *compressor) { struct zswap_pool *pool; @@ -471,8 +425,6 @@ static struct zswap_pool *zswap_pool_fin list_for_each_entry_rcu(pool, &zswap_pools, list) { if (strcmp(pool->tfm_name, compressor)) continue; - if (strcmp(zpool_get_type(pool->zpool), type)) - continue; /* if we can't get it, it's about to be destroyed */ if (!zswap_pool_tryget(pool)) continue; @@ -499,7 +451,7 @@ unsigned long zswap_total_pages(void) rcu_read_lock(); list_for_each_entry_rcu(pool, &zswap_pools, list) - total += zpool_get_total_pages(pool->zpool); + total += zs_get_total_pages(pool->zs_pool); rcu_read_unlock(); return total; @@ -524,33 +476,22 @@ static bool zswap_check_limits(void) * 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) +static int zswap_compressor_param_set(const char *val, const struct kernel_param *kp) { struct zswap_pool *pool, *put_pool = NULL; char *s = strstrip((char *)val); + bool create_pool = false; 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. - */ + /* Handled in zswap_setup() */ ret = param_set_charp(s, kp); break; case ZSWAP_INIT_SUCCEED: - new_pool = zswap_pool_changed(s, kp); + if (!zswap_has_pool || strcmp(s, *(char **)kp->arg)) + create_pool = true; break; case ZSWAP_INIT_FAILED: pr_err("can't set param, initialization failed\n"); @@ -558,30 +499,17 @@ static int __zswap_param_set(const char } mutex_unlock(&zswap_init_lock); - /* no need to create a new pool, return directly */ - if (!new_pool) + if (!create_pool) return ret; - if (!type) { - if (!zpool_has_pool(s)) { - pr_err("zpool %s not available\n", s); - return -ENOENT; - } - type = s; - } else if (!compressor) { - if (!crypto_has_acomp(s, 0, 0)) { - pr_err("compressor %s not available\n", s); - return -ENOENT; - } - compressor = s; - } else { - WARN_ON(1); - return -EINVAL; + if (!crypto_has_acomp(s, 0, 0)) { + pr_err("compressor %s not available\n", s); + return -ENOENT; } spin_lock_bh(&zswap_pools_lock); - pool = zswap_pool_find_get(type, compressor); + pool = zswap_pool_find_get(s); if (pool) { zswap_pool_debug("using existing", pool); WARN_ON(pool == zswap_pool_current()); @@ -591,7 +519,7 @@ static int __zswap_param_set(const char spin_unlock_bh(&zswap_pools_lock); if (!pool) - pool = zswap_pool_create(type, compressor); + pool = zswap_pool_create(s); else { /* * Restore the initial ref dropped by percpu_ref_kill() @@ -616,7 +544,8 @@ static int __zswap_param_set(const char list_add_rcu(&pool->list, &zswap_pools); zswap_has_pool = true; } else if (pool) { - /* add the possibly pre-existing pool to the end of the pools + /* + * Add the possibly pre-existing pool to the end of the pools * list; if it's new (and empty) then it'll be removed and * destroyed by the put after we drop the lock */ @@ -626,18 +555,8 @@ static int __zswap_param_set(const char spin_unlock_bh(&zswap_pools_lock); - if (!zswap_has_pool && !pool) { - /* if initial pool creation failed, and this pool creation also - * failed, maybe both compressor and zpool params were bad. - * Allow changing this param, so pool creation will succeed - * when the other param is changed. We already verified this - * param is ok in the zpool_has_pool() or crypto_has_acomp() - * checks above. - */ - ret = param_set_charp(s, kp); - } - - /* drop the ref from either the old current pool, + /* + * Drop the ref from either the old current pool, * or the new pool we failed to add */ if (put_pool) @@ -646,18 +565,6 @@ static int __zswap_param_set(const char return ret; } -static int zswap_compressor_param_set(const char *val, - const struct kernel_param *kp) -{ - return __zswap_param_set(val, kp, zswap_zpool_type, NULL); -} - -static int zswap_zpool_param_set(const char *val, - const struct kernel_param *kp) -{ - return __zswap_param_set(val, kp, NULL, zswap_compressor); -} - static int zswap_enabled_param_set(const char *val, const struct kernel_param *kp) { @@ -801,13 +708,13 @@ static void zswap_entry_cache_free(struc } /* - * Carries out the common pattern of freeing and entry's zpool allocation, + * Carries out the common pattern of freeing an entry's zsmalloc allocation, * freeing the entry itself, and decrementing the number of stored pages. */ static void zswap_entry_free(struct zswap_entry *entry) { zswap_lru_del(&zswap_list_lru, entry); - zpool_free(entry->pool->zpool, entry->handle); + zs_free(entry->pool->zs_pool, entry->handle); zswap_pool_put(entry->pool); if (entry->objcg) { obj_cgroup_uncharge_zswap(entry->objcg, entry->length); @@ -949,7 +856,6 @@ static bool zswap_compress(struct page * int comp_ret = 0, alloc_ret = 0; unsigned int dlen = PAGE_SIZE; unsigned long handle; - struct zpool *zpool; gfp_t gfp; u8 *dst; bool mapped = false; @@ -997,13 +903,14 @@ static bool zswap_compress(struct page * mapped = true; } - zpool = pool->zpool; gfp = GFP_NOWAIT | __GFP_NORETRY | __GFP_HIGHMEM | __GFP_MOVABLE; - alloc_ret = zpool_malloc(zpool, dlen, gfp, &handle, page_to_nid(page)); - if (alloc_ret) + handle = zs_malloc(pool->zs_pool, dlen, gfp, page_to_nid(page)); + if (IS_ERR_VALUE(handle)) { + alloc_ret = PTR_ERR((void *)handle); goto unlock; + } - zpool_obj_write(zpool, handle, dst, dlen); + zs_obj_write(pool->zs_pool, handle, dst, dlen); entry->handle = handle; entry->length = dlen; @@ -1023,14 +930,14 @@ unlock: static bool zswap_decompress(struct zswap_entry *entry, struct folio *folio) { - struct zpool *zpool = entry->pool->zpool; + struct zswap_pool *pool = entry->pool; struct scatterlist input, output; struct crypto_acomp_ctx *acomp_ctx; int decomp_ret = 0, dlen = PAGE_SIZE; u8 *src, *obj; - acomp_ctx = acomp_ctx_get_cpu_lock(entry->pool); - obj = zpool_obj_read_begin(zpool, entry->handle, acomp_ctx->buffer); + acomp_ctx = acomp_ctx_get_cpu_lock(pool); + obj = zs_obj_read_begin(pool->zs_pool, entry->handle, acomp_ctx->buffer); /* zswap entries of length PAGE_SIZE are not compressed. */ if (entry->length == PAGE_SIZE) { @@ -1039,7 +946,7 @@ static bool zswap_decompress(struct zswa } /* - * zpool_obj_read_begin() might return a kmap address of highmem when + * zs_obj_read_begin() might return a kmap address of highmem when * acomp_ctx->buffer is not used. However, sg_init_one() does not * handle highmem addresses, so copy the object to acomp_ctx->buffer. */ @@ -1059,7 +966,7 @@ static bool zswap_decompress(struct zswa dlen = acomp_ctx->req->dlen; read_done: - zpool_obj_read_end(zpool, entry->handle, obj); + zs_obj_read_end(pool->zs_pool, entry->handle, obj); acomp_ctx_put_unlock(acomp_ctx); if (!decomp_ret && dlen == PAGE_SIZE) @@ -1576,7 +1483,7 @@ static bool zswap_store_page(struct page return true; store_failed: - zpool_free(pool->zpool, entry->handle); + zs_free(pool->zs_pool, entry->handle); compress_failed: zswap_entry_cache_free(entry); return false; @@ -1906,8 +1813,7 @@ static int zswap_setup(void) pool = __zswap_pool_create_fallback(); if (pool) { - pr_info("loaded using pool %s/%s\n", pool->tfm_name, - zpool_get_type(pool->zpool)); + pr_info("loaded using pool %s\n", pool->tfm_name); list_add(&pool->list, &zswap_pools); zswap_has_pool = true; static_branch_enable(&zswap_ever_enabled); _ Patches currently in -mm which might be from hannes@cmpxchg.org are mm-zswap-interact-directly-with-zsmalloc.patch mm-remove-unused-zpool-layer.patch mm-zpdesc-minor-naming-and-comment-corrections.patch