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Thu, 17 Nov 2022 21:52:01 -0800 (PST) Date: Fri, 18 Nov 2022 00:52:25 -0500 From: Johannes Weiner To: Minchan Kim Cc: Nhat Pham , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ngupta@vflare.org, senozhatsky@chromium.org, sjenning@redhat.com, ddstreet@ieee.org, vitaly.wool@konsulko.com Subject: Re: [PATCH v4 4/5] zsmalloc: Add ops fields to zs_pool to store evict handlers Message-ID: References: <20221117163839.230900-1-nphamcs@gmail.com> <20221117163839.230900-5-nphamcs@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1668750723; a=rsa-sha256; cv=none; b=k6+6lEUKGrRI6TWm+X08ewNnjwaCizrZn3o6N80LDe7LwgcW5YDZfX+4YTmfLLb8oCdz6m CfTD7k2oDIGx1l/oXJSHcJNOcT6RYUF9B+cHYVM0BmB2MM8x9IcSiUdjt3F2ibibA58UIF OgAwc0ZqsBovX0ueI/cqXQHTXl84iUU= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=cmpxchg-org.20210112.gappssmtp.com header.s=20210112 header.b=JKH1eR15; 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dmarc=pass (policy=none) header.from=cmpxchg.org X-Rspamd-Server: rspam04 X-Rspam-User: X-HE-Tag: 1668750722-971668 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Nov 18, 2022 at 12:15:15AM -0500, Johannes Weiner wrote: > @@ -22,8 +22,6 @@ struct zpool { > struct zpool_driver *driver; > void *pool; > const struct zpool_ops *ops; > - bool evictable; > - bool can_sleep_mapped; > }; Oops, forgot to remove ops, which is unused too. --- >From 408c8b9caafa960da703762d9aaec09a6575b207 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 17 Nov 2022 23:49:30 -0500 Subject: [PATCH] zpool: clean out dead code There is a lot of provision for flexibility that isn't actually needed or used. Zswap (the only zpool user) always passes zpool_ops with an .evict method set. The backends who reclaim only do so for zswap, so they can also directly call zpool_ops without indirection or checks. Finally, there is no need to check the retries parameters and bail with -EINVAL in the reclaim function, when that's called just a few lines below with a hard-coded 8. There is no need to duplicate the evictable and sleep_mapped attrs from the driver in zpool_ops. Signed-off-by: Johannes Weiner --- mm/z3fold.c | 36 +++++------------------------------- mm/zbud.c | 32 +++++--------------------------- mm/zpool.c | 10 ++-------- 3 files changed, 12 insertions(+), 66 deletions(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index cf71da10d04e..a4de0c317ac7 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -68,9 +68,6 @@ * Structures *****************/ struct z3fold_pool; -struct z3fold_ops { - int (*evict)(struct z3fold_pool *pool, unsigned long handle); -}; enum buddy { HEADLESS = 0, @@ -138,8 +135,6 @@ struct z3fold_header { * @stale: list of pages marked for freeing * @pages_nr: number of z3fold pages in the pool. * @c_handle: cache for z3fold_buddy_slots allocation - * @ops: pointer to a structure of user defined operations specified at - * pool creation time. * @zpool: zpool driver * @zpool_ops: zpool operations structure with an evict callback * @compact_wq: workqueue for page layout background optimization @@ -158,7 +153,6 @@ struct z3fold_pool { struct list_head stale; atomic64_t pages_nr; struct kmem_cache *c_handle; - const struct z3fold_ops *ops; struct zpool *zpool; const struct zpool_ops *zpool_ops; struct workqueue_struct *compact_wq; @@ -907,13 +901,11 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, * z3fold_create_pool() - create a new z3fold pool * @name: pool name * @gfp: gfp flags when allocating the z3fold pool structure - * @ops: user-defined operations for the z3fold pool * * Return: pointer to the new z3fold pool or NULL if the metadata allocation * failed. */ -static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, - const struct z3fold_ops *ops) +static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp) { struct z3fold_pool *pool = NULL; int i, cpu; @@ -949,7 +941,6 @@ static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, if (!pool->release_wq) goto out_wq; INIT_WORK(&pool->work, free_pages_work); - pool->ops = ops; return pool; out_wq: @@ -1230,10 +1221,6 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) slots.pool = (unsigned long)pool | (1 << HANDLES_NOFREE); spin_lock(&pool->lock); - if (!pool->ops || !pool->ops->evict || retries == 0) { - spin_unlock(&pool->lock); - return -EINVAL; - } for (i = 0; i < retries; i++) { if (list_empty(&pool->lru)) { spin_unlock(&pool->lock); @@ -1319,17 +1306,17 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) } /* Issue the eviction callback(s) */ if (middle_handle) { - ret = pool->ops->evict(pool, middle_handle); + ret = pool->zpool_ops->evict(pool->zpool, middle_handle); if (ret) goto next; } if (first_handle) { - ret = pool->ops->evict(pool, first_handle); + ret = pool->zpool_ops->evict(pool->zpool, first_handle); if (ret) goto next; } if (last_handle) { - ret = pool->ops->evict(pool, last_handle); + ret = pool->zpool_ops->evict(pool->zpool, last_handle); if (ret) goto next; } @@ -1593,26 +1580,13 @@ static const struct movable_operations z3fold_mops = { * zpool ****************/ -static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) -{ - if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) - return pool->zpool_ops->evict(pool->zpool, handle); - else - return -ENOENT; -} - -static const struct z3fold_ops z3fold_zpool_ops = { - .evict = z3fold_zpool_evict -}; - static void *z3fold_zpool_create(const char *name, gfp_t gfp, const struct zpool_ops *zpool_ops, struct zpool *zpool) { struct z3fold_pool *pool; - pool = z3fold_create_pool(name, gfp, - zpool_ops ? &z3fold_zpool_ops : NULL); + pool = z3fold_create_pool(name, gfp); if (pool) { pool->zpool = zpool; pool->zpool_ops = zpool_ops; diff --git a/mm/zbud.c b/mm/zbud.c index 6348932430b8..3acd26193920 100644 --- a/mm/zbud.c +++ b/mm/zbud.c @@ -74,10 +74,6 @@ struct zbud_pool; -struct zbud_ops { - int (*evict)(struct zbud_pool *pool, unsigned long handle); -}; - /** * struct zbud_pool - stores metadata for each zbud pool * @lock: protects all pool fields and first|last_chunk fields of any @@ -90,8 +86,6 @@ struct zbud_ops { * @lru: list tracking the zbud pages in LRU order by most recently * added buddy. * @pages_nr: number of zbud pages in the pool. - * @ops: pointer to a structure of user defined operations specified at - * pool creation time. * @zpool: zpool driver * @zpool_ops: zpool operations structure with an evict callback * @@ -110,7 +104,6 @@ struct zbud_pool { }; struct list_head lru; u64 pages_nr; - const struct zbud_ops *ops; struct zpool *zpool; const struct zpool_ops *zpool_ops; }; @@ -212,12 +205,11 @@ static int num_free_chunks(struct zbud_header *zhdr) /** * zbud_create_pool() - create a new zbud pool * @gfp: gfp flags when allocating the zbud pool structure - * @ops: user-defined operations for the zbud pool * * Return: pointer to the new zbud pool or NULL if the metadata allocation * failed. */ -static struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops) +static struct zbud_pool *zbud_create_pool(gfp_t gfp) { struct zbud_pool *pool; int i; @@ -231,7 +223,6 @@ static struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops) INIT_LIST_HEAD(&pool->buddied); INIT_LIST_HEAD(&pool->lru); pool->pages_nr = 0; - pool->ops = ops; return pool; } @@ -419,8 +410,7 @@ static int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries) unsigned long first_handle = 0, last_handle = 0; spin_lock(&pool->lock); - if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) || - retries == 0) { + if (list_empty(&pool->lru)) { spin_unlock(&pool->lock); return -EINVAL; } @@ -444,12 +434,12 @@ static int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries) /* Issue the eviction callback(s) */ if (first_handle) { - ret = pool->ops->evict(pool, first_handle); + ret = pool->zpool_ops->evict(pool->zpool, first_handle); if (ret) goto next; } if (last_handle) { - ret = pool->ops->evict(pool, last_handle); + ret = pool->zpool_ops->evict(pool->zpool, last_handle); if (ret) goto next; } @@ -524,25 +514,13 @@ static u64 zbud_get_pool_size(struct zbud_pool *pool) * zpool ****************/ -static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle) -{ - if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) - return pool->zpool_ops->evict(pool->zpool, handle); - else - return -ENOENT; -} - -static const struct zbud_ops zbud_zpool_ops = { - .evict = zbud_zpool_evict -}; - static void *zbud_zpool_create(const char *name, gfp_t gfp, const struct zpool_ops *zpool_ops, struct zpool *zpool) { struct zbud_pool *pool; - pool = zbud_create_pool(gfp, zpool_ops ? &zbud_zpool_ops : NULL); + pool = zbud_create_pool(gfp); if (pool) { pool->zpool = zpool; pool->zpool_ops = zpool_ops; diff --git a/mm/zpool.c b/mm/zpool.c index 68facc193496..fc3a9893e107 100644 --- a/mm/zpool.c +++ b/mm/zpool.c @@ -21,9 +21,6 @@ struct zpool { struct zpool_driver *driver; void *pool; - const struct zpool_ops *ops; - bool evictable; - bool can_sleep_mapped; }; static LIST_HEAD(drivers_head); @@ -177,9 +174,6 @@ struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp, zpool->driver = driver; zpool->pool = driver->create(name, gfp, ops, zpool); - zpool->ops = ops; - zpool->evictable = driver->shrink && ops && ops->evict; - zpool->can_sleep_mapped = driver->sleep_mapped; if (!zpool->pool) { pr_err("couldn't create %s pool\n", type); @@ -380,7 +374,7 @@ u64 zpool_get_total_size(struct zpool *zpool) */ bool zpool_evictable(struct zpool *zpool) { - return zpool->evictable; + return zpool->driver->shrink; } /** @@ -391,7 +385,7 @@ bool zpool_evictable(struct zpool *zpool) */ bool zpool_can_sleep_mapped(struct zpool *zpool) { - return zpool->can_sleep_mapped; + return zpool->driver->sleep_mapped; } MODULE_LICENSE("GPL"); -- 2.38.1