From 0b2f5ea1aa39c0ed34bdadb53faf519e3d84ac4a Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:25:17 +0800 Subject: drm/ttm: introduce pool_shrink_rwsem MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, synchronize_shrinkers() is only used by TTM pool. It only requires that no shrinkers run in parallel. After we use RCU+refcount method to implement the lockless slab shrink, we can not use shrinker_rwsem or synchronize_rcu() to guarantee that all shrinker invocations have seen an update before freeing memory. So we introduce a new pool_shrink_rwsem to implement a private ttm_pool_synchronize_shrinkers(), so as to achieve the same purpose. Link: https://lkml.kernel.org/r/20230911092517.64141-5-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Reviewed-by: Christian König Acked-by: Daniel Vetter Cc: Christian Brauner Cc: Chuck Lever Cc: Daniel Vetter Cc: Darrick J. Wong Cc: Dave Chinner Cc: Greg Kroah-Hartman Cc: Joel Fernandes Cc: Kirill Tkhai Cc: Paul E. McKenney Cc: Roman Gushchin Cc: Sergey Senozhatsky Cc: Steven Price Cc: Theodore Ts'o Cc: Vlastimil Babka Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Coly Li Cc: Dai Ngo Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Sean Paul Cc: Song Liu Cc: Stefano Stabellini Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- drivers/gpu/drm/ttm/ttm_pool.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/ttm/ttm_pool.c') diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index cddb9151d20f..648ca70403a7 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -74,6 +74,7 @@ static struct ttm_pool_type global_dma32_uncached[MAX_ORDER + 1]; static spinlock_t shrinker_lock; static struct list_head shrinker_list; static struct shrinker mm_shrinker; +static DECLARE_RWSEM(pool_shrink_rwsem); /* Allocate pages of size 1 << order with the given gfp_flags */ static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags, @@ -317,6 +318,7 @@ static unsigned int ttm_pool_shrink(void) unsigned int num_pages; struct page *p; + down_read(&pool_shrink_rwsem); spin_lock(&shrinker_lock); pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list); list_move_tail(&pt->shrinker_list, &shrinker_list); @@ -329,6 +331,7 @@ static unsigned int ttm_pool_shrink(void) } else { num_pages = 0; } + up_read(&pool_shrink_rwsem); return num_pages; } @@ -572,6 +575,18 @@ void ttm_pool_init(struct ttm_pool *pool, struct device *dev, } EXPORT_SYMBOL(ttm_pool_init); +/** + * ttm_pool_synchronize_shrinkers - Wait for all running shrinkers to complete. + * + * This is useful to guarantee that all shrinker invocations have seen an + * update, before freeing memory, similar to rcu. + */ +static void ttm_pool_synchronize_shrinkers(void) +{ + down_write(&pool_shrink_rwsem); + up_write(&pool_shrink_rwsem); +} + /** * ttm_pool_fini - Cleanup a pool * @@ -593,7 +608,7 @@ void ttm_pool_fini(struct ttm_pool *pool) /* We removed the pool types from the LRU, but we need to also make sure * that no shrinker is concurrently freeing pages from the pool. */ - synchronize_shrinkers(); + ttm_pool_synchronize_shrinkers(); } EXPORT_SYMBOL(ttm_pool_fini); -- cgit v1.2.3 From d35b5c98c1f1ea44d4652a78163ce6d0e6ec2b78 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:03 +0800 Subject: drm/ttm: dynamically allocate the drm-ttm_pool shrinker Use new APIs to dynamically allocate the drm-ttm_pool shrinker. Link: https://lkml.kernel.org/r/20230911094444.68966-5-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Acked-by: Daniel Vetter Cc: Christian Koenig Cc: Huang Rui Cc: David Airlie Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Christian Brauner Cc: Chuck Lever Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Dave Hansen Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Greg Kroah-Hartman Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Kirill Tkhai Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Paul E. McKenney Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Roman Gushchin Cc: Sean Paul Cc: Sergey Senozhatsky Cc: Song Liu Cc: Stefano Stabellini Cc: Steven Price Cc: "Theodore Ts'o" Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- drivers/gpu/drm/ttm/ttm_pool.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) (limited to 'drivers/gpu/drm/ttm/ttm_pool.c') diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index 648ca70403a7..fe610a3cace0 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -73,7 +73,7 @@ static struct ttm_pool_type global_dma32_uncached[MAX_ORDER + 1]; static spinlock_t shrinker_lock; static struct list_head shrinker_list; -static struct shrinker mm_shrinker; +static struct shrinker *mm_shrinker; static DECLARE_RWSEM(pool_shrink_rwsem); /* Allocate pages of size 1 << order with the given gfp_flags */ @@ -749,8 +749,8 @@ static int ttm_pool_debugfs_shrink_show(struct seq_file *m, void *data) struct shrink_control sc = { .gfp_mask = GFP_NOFS }; fs_reclaim_acquire(GFP_KERNEL); - seq_printf(m, "%lu/%lu\n", ttm_pool_shrinker_count(&mm_shrinker, &sc), - ttm_pool_shrinker_scan(&mm_shrinker, &sc)); + seq_printf(m, "%lu/%lu\n", ttm_pool_shrinker_count(mm_shrinker, &sc), + ttm_pool_shrinker_scan(mm_shrinker, &sc)); fs_reclaim_release(GFP_KERNEL); return 0; @@ -794,10 +794,17 @@ int ttm_pool_mgr_init(unsigned long num_pages) &ttm_pool_debugfs_shrink_fops); #endif - mm_shrinker.count_objects = ttm_pool_shrinker_count; - mm_shrinker.scan_objects = ttm_pool_shrinker_scan; - mm_shrinker.seeks = 1; - return register_shrinker(&mm_shrinker, "drm-ttm_pool"); + mm_shrinker = shrinker_alloc(0, "drm-ttm_pool"); + if (!mm_shrinker) + return -ENOMEM; + + mm_shrinker->count_objects = ttm_pool_shrinker_count; + mm_shrinker->scan_objects = ttm_pool_shrinker_scan; + mm_shrinker->seeks = 1; + + shrinker_register(mm_shrinker); + + return 0; } /** @@ -817,6 +824,6 @@ void ttm_pool_mgr_fini(void) ttm_pool_type_fini(&global_dma32_uncached[i]); } - unregister_shrinker(&mm_shrinker); + shrinker_free(mm_shrinker); WARN_ON(!list_empty(&shrinker_list)); } -- cgit v1.2.3