From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67287C4321E for ; Wed, 2 Nov 2022 21:28:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230296AbiKBV2f (ORCPT ); Wed, 2 Nov 2022 17:28:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230499AbiKBV2P (ORCPT ); Wed, 2 Nov 2022 17:28:15 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AEEBAE0E1 for ; Wed, 2 Nov 2022 14:28:13 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 36C9CB8250C for ; Wed, 2 Nov 2022 21:28:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6CA7C433B5; Wed, 2 Nov 2022 21:28:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1667424490; bh=Gsd7aO+UBIZnIWlJKf3YfQcVH+EUDwVNvmep3V7MOQE=; h=Date:To:From:Subject:From; b=b+/zH/sXBnrCmqAU/SNfiZqWqkOlIMbcI3gAcQzQcUvOsM9OIjNX/OwzVw3f2VRVx /jWDsOyJkUDhcbCVi8a6IAbc3pdIdd+KeP0MZgx14wrVIyQPvOWvsDA2bKLkOViyxF 417gm1Jbxqt5cgzST1sw2+jotiQ84B96/sMeDgVg= Date: Wed, 02 Nov 2022 14:28:10 -0700 To: mm-commits@vger.kernel.org, vitaly.wool@konsulko.com, sjenning@redhat.com, senozhatsky@chromium.org, ngupta@vflare.org, minchan@kernel.org, hannes@cmpxchg.org, ddstreet@ieee.org, nphamcs@gmail.com, akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] zsmalloc-implement-writeback-mechanism-for-zsmalloc.patch removed from -mm tree Message-Id: <20221102212810.C6CA7C433B5@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: zsmalloc: implement writeback mechanism for zsmalloc has been removed from the -mm tree. Its filename was zsmalloc-implement-writeback-mechanism-for-zsmalloc.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Nhat Pham Subject: zsmalloc: implement writeback mechanism for zsmalloc Date: Thu, 27 Oct 2022 11:27:36 -0700 This commit adds the writeback mechanism for zsmalloc, analogous to the zbud allocator. Zsmalloc will attempt to determine the coldest zspage (i.e least recently used) in the pool, and attempt to write back all the stored compressed objects via the pool's evict handler. Link: https://lkml.kernel.org/r/20221027182736.513530-1-nphamcs@gmail.com Signed-off-by: Nhat Pham Acked-by: Johannes Weiner Cc: Dan Streetman Cc: Minchan Kim Cc: Nitin Gupta Cc: Sergey Senozhatsky Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton --- mm/zsmalloc.c | 198 ++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 183 insertions(+), 15 deletions(-) --- a/mm/zsmalloc.c~zsmalloc-implement-writeback-mechanism-for-zsmalloc +++ a/mm/zsmalloc.c @@ -279,10 +279,13 @@ struct zspage { /* links the zspage to the lru list in the pool */ struct list_head lru; + bool under_reclaim; + + /* list of unfreed handles whose objects have been reclaimed */ + unsigned long *deferred_handles; + struct zs_pool *pool; -#ifdef CONFIG_COMPACTION rwlock_t lock; -#endif }; struct mapping_area { @@ -303,10 +306,11 @@ static bool ZsHugePage(struct zspage *zs return zspage->huge; } -#ifdef CONFIG_COMPACTION static void migrate_lock_init(struct zspage *zspage); static void migrate_read_lock(struct zspage *zspage); static void migrate_read_unlock(struct zspage *zspage); + +#ifdef CONFIG_COMPACTION static void migrate_write_lock(struct zspage *zspage); static void migrate_write_lock_nested(struct zspage *zspage); static void migrate_write_unlock(struct zspage *zspage); @@ -314,9 +318,6 @@ static void kick_deferred_free(struct zs static void init_deferred_free(struct zs_pool *pool); static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage); #else -static void migrate_lock_init(struct zspage *zspage) {} -static void migrate_read_lock(struct zspage *zspage) {} -static void migrate_read_unlock(struct zspage *zspage) {} static void migrate_write_lock(struct zspage *zspage) {} static void migrate_write_lock_nested(struct zspage *zspage) {} static void migrate_write_unlock(struct zspage *zspage) {} @@ -445,6 +446,27 @@ static void zs_zpool_free(void *pool, un zs_free(pool, handle); } +static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries); + +static int zs_zpool_shrink(void *pool, unsigned int pages, + unsigned int *reclaimed) +{ + unsigned int total = 0; + int ret = -EINVAL; + + while (total < pages) { + ret = zs_reclaim_page(pool, 8); + if (ret < 0) + break; + total++; + } + + if (reclaimed) + *reclaimed = total; + + return ret; +} + static void *zs_zpool_map(void *pool, unsigned long handle, enum zpool_mapmode mm) { @@ -483,6 +505,7 @@ static struct zpool_driver zs_zpool_driv .malloc_support_movable = true, .malloc = zs_zpool_malloc, .free = zs_zpool_free, + .shrink = zs_zpool_shrink, .map = zs_zpool_map, .unmap = zs_zpool_unmap, .total_size = zs_zpool_total_size, @@ -956,6 +979,21 @@ unlock: return 0; } +/* + * Free all the deferred handles whose objects are freed in zs_free. + */ +static void free_handles(struct zs_pool *pool, struct zspage *zspage) +{ + unsigned long handle = (unsigned long) zspage->deferred_handles; + + while (handle) { + unsigned long nxt_handle = handle_to_obj(handle); + + cache_free_handle(pool, handle); + handle = nxt_handle; + } +} + static void __free_zspage(struct zs_pool *pool, struct size_class *class, struct zspage *zspage) { @@ -970,6 +1008,9 @@ static void __free_zspage(struct zs_pool VM_BUG_ON(get_zspage_inuse(zspage)); VM_BUG_ON(fg != ZS_EMPTY); + /* Free all deferred handles from zs_free */ + free_handles(pool, zspage); + next = page = get_first_page(zspage); do { VM_BUG_ON_PAGE(!PageLocked(page), page); @@ -1052,6 +1093,8 @@ static void init_zspage(struct size_clas } INIT_LIST_HEAD(&zspage->lru); + zspage->under_reclaim = false; + zspage->deferred_handles = NULL; set_freeobj(zspage, 0); } @@ -1473,11 +1516,8 @@ unsigned long zs_malloc(struct zs_pool * fix_fullness_group(class, zspage); record_obj(handle, obj); class_stat_inc(class, OBJ_USED, 1); - /* Move the zspage to front of pool's LRU */ - move_to_front(pool, zspage); - spin_unlock(&pool->lock); - return handle; + goto out; } spin_unlock(&pool->lock); @@ -1501,6 +1541,8 @@ unsigned long zs_malloc(struct zs_pool * /* We completely set up zspage so mark them as movable */ SetZsPageMovable(pool, zspage); + +out: /* Move the zspage to front of pool's LRU */ move_to_front(pool, zspage); spin_unlock(&pool->lock); @@ -1558,12 +1600,24 @@ void zs_free(struct zs_pool *pool, unsig obj_free(class->size, obj); class_stat_dec(class, OBJ_USED, 1); + + if (zspage->under_reclaim) { + /* + * Reclaim needs the handles during writeback. It'll free + * them along with the zspage when it's done with them. + * + * Record current deferred handle at the memory location + * whose address is given by handle. + */ + record_obj(handle, (unsigned long) zspage->deferred_handles); + zspage->deferred_handles = (unsigned long *) handle; + spin_unlock(&pool->lock); + return; + } fullness = fix_fullness_group(class, zspage); - if (fullness != ZS_EMPTY) - goto out; + if (fullness == ZS_EMPTY) + free_zspage(pool, class, zspage); - free_zspage(pool, class, zspage); -out: spin_unlock(&pool->lock); cache_free_handle(pool, handle); } @@ -1763,7 +1817,7 @@ static enum fullness_group putback_zspag return fullness; } -#ifdef CONFIG_COMPACTION +#if defined(CONFIG_ZPOOL) || defined(CONFIG_COMPACTION) /* * To prevent zspage destroy during migration, zspage freeing should * hold locks of all pages in the zspage. @@ -1805,6 +1859,24 @@ static void lock_zspage(struct zspage *z } migrate_read_unlock(zspage); } +#endif /* defined(CONFIG_ZPOOL) || defined(CONFIG_COMPACTION) */ + +#ifdef CONFIG_ZPOOL +/* + * Unlocks all the pages of the zspage. + * + * pool->lock must be held before this function is called + * to prevent the underlying pages from migrating. + */ +static void unlock_zspage(struct zspage *zspage) +{ + struct page *page = get_first_page(zspage); + + do { + unlock_page(page); + } while ((page = get_next_page(page)) != NULL); +} +#endif /* CONFIG_ZPOOL */ static void migrate_lock_init(struct zspage *zspage) { @@ -1821,6 +1893,7 @@ static void migrate_read_unlock(struct z read_unlock(&zspage->lock); } +#ifdef CONFIG_COMPACTION static void migrate_write_lock(struct zspage *zspage) { write_lock(&zspage->lock); @@ -2381,6 +2454,101 @@ void zs_destroy_pool(struct zs_pool *poo } EXPORT_SYMBOL_GPL(zs_destroy_pool); +#ifdef CONFIG_ZPOOL +static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries) +{ + int i, obj_idx, ret = 0; + unsigned long handle; + struct zspage *zspage; + struct page *page; + enum fullness_group fullness; + + /* Lock LRU and fullness list */ + spin_lock(&pool->lock); + if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) || + retries == 0) { + spin_unlock(&pool->lock); + return -EINVAL; + } + + for (i = 0; i < retries; i++) { + struct size_class *class; + + zspage = list_last_entry(&pool->lru, struct zspage, lru); + list_del(&zspage->lru); + + /* zs_free may free objects, but not the zspage and handles */ + zspage->under_reclaim = true; + + /* Lock backing pages into place */ + lock_zspage(zspage); + + class = zspage_class(pool, zspage); + fullness = get_fullness_group(class, zspage); + + /* Lock out object allocations and object compaction */ + remove_zspage(class, zspage, fullness); + + spin_unlock(&pool->lock); + + obj_idx = 0; + page = zspage->first_page; + while (1) { + handle = find_alloced_obj(class, page, &obj_idx); + if (!handle) { + page = get_next_page(page); + if (!page) + break; + obj_idx = 0; + continue; + } + + /* + * This will write the object and call + * zs_free. + * + * zs_free will free the object, but the + * under_reclaim flag prevents it from freeing + * the zspage altogether. This is necessary so + * that we can continue working with the + * zspage potentially after the last object + * has been freed. + */ + ret = pool->ops->evict(pool, handle); + if (ret) + goto next; + + obj_idx++; + } + +next: + /* For freeing the zspage, or putting it back in the pool and LRU list. */ + spin_lock(&pool->lock); + zspage->under_reclaim = false; + + if (!get_zspage_inuse(zspage)) { + /* + * Fullness went stale as zs_free() won't touch it + * while the page is removed from the pool. Fix it + * up for the check in __free_zspage(). + */ + zspage->fullness = ZS_EMPTY; + + __free_zspage(pool, class, zspage); + spin_unlock(&pool->lock); + return 0; + } + + putback_zspage(class, zspage); + list_add(&zspage->lru, &pool->lru); + unlock_zspage(zspage); + } + + spin_unlock(&pool->lock); + return -EAGAIN; +} +#endif /* CONFIG_ZPOOL */ + static int __init zs_init(void) { int ret; _ Patches currently in -mm which might be from nphamcs@gmail.com are