From b4c2b231c3ba155623591fb6301ed97b95e1c039 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Fri, 17 Aug 2018 15:47:29 -0700 Subject: mm: assign id to every memcg-aware shrinker Introduce shrinker::id number, which is used to enumerate memcg-aware shrinkers. The number start from 0, and the code tries to maintain it as small as possible. This will be used to represent a memcg-aware shrinkers in memcg shrinkers map. Since all memcg-aware shrinkers are based on list_lru, which is per-memcg in case of !CONFIG_MEMCG_KMEM only, the new functionality will be under this config option. [ktkhai@virtuozzo.com: v9] Link: http://lkml.kernel.org/r/153112546435.4097.10607140323811756557.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/153063054586.1818.6041047871606697364.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai Acked-by: Vladimir Davydov Tested-by: Shakeel Butt Cc: Al Viro Cc: Andrey Ryabinin Cc: Chris Wilson Cc: Greg Kroah-Hartman Cc: Guenter Roeck Cc: "Huang, Ying" Cc: Johannes Weiner Cc: Josef Bacik Cc: Li RongQing Cc: Matthew Wilcox Cc: Matthias Kaehlcke Cc: Mel Gorman Cc: Michal Hocko Cc: Minchan Kim Cc: Philippe Ombredanne Cc: Roman Gushchin Cc: Sahitya Tummala Cc: Stephen Rothwell Cc: Tetsuo Handa Cc: Thomas Gleixner Cc: Waiman Long Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index a00d94530e57..5cb4f779ea4a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -169,6 +169,50 @@ unsigned long vm_total_pages; static LIST_HEAD(shrinker_list); static DECLARE_RWSEM(shrinker_rwsem); +#ifdef CONFIG_MEMCG_KMEM +static DEFINE_IDR(shrinker_idr); +static int shrinker_nr_max; + +static int prealloc_memcg_shrinker(struct shrinker *shrinker) +{ + int id, ret = -ENOMEM; + + down_write(&shrinker_rwsem); + /* This may call shrinker, so it must use down_read_trylock() */ + id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL); + if (id < 0) + goto unlock; + + if (id >= shrinker_nr_max) + shrinker_nr_max = id + 1; + shrinker->id = id; + ret = 0; +unlock: + up_write(&shrinker_rwsem); + return ret; +} + +static void unregister_memcg_shrinker(struct shrinker *shrinker) +{ + int id = shrinker->id; + + BUG_ON(id < 0); + + down_write(&shrinker_rwsem); + idr_remove(&shrinker_idr, id); + up_write(&shrinker_rwsem); +} +#else /* CONFIG_MEMCG_KMEM */ +static int prealloc_memcg_shrinker(struct shrinker *shrinker) +{ + return 0; +} + +static void unregister_memcg_shrinker(struct shrinker *shrinker) +{ +} +#endif /* CONFIG_MEMCG_KMEM */ + #ifdef CONFIG_MEMCG static bool global_reclaim(struct scan_control *sc) { @@ -313,11 +357,28 @@ int prealloc_shrinker(struct shrinker *shrinker) shrinker->nr_deferred = kzalloc(size, GFP_KERNEL); if (!shrinker->nr_deferred) return -ENOMEM; + + if (shrinker->flags & SHRINKER_MEMCG_AWARE) { + if (prealloc_memcg_shrinker(shrinker)) + goto free_deferred; + } + return 0; + +free_deferred: + kfree(shrinker->nr_deferred); + shrinker->nr_deferred = NULL; + return -ENOMEM; } void free_prealloced_shrinker(struct shrinker *shrinker) { + if (!shrinker->nr_deferred) + return; + + if (shrinker->flags & SHRINKER_MEMCG_AWARE) + unregister_memcg_shrinker(shrinker); + kfree(shrinker->nr_deferred); shrinker->nr_deferred = NULL; } @@ -347,6 +408,8 @@ void unregister_shrinker(struct shrinker *shrinker) { if (!shrinker->nr_deferred) return; + if (shrinker->flags & SHRINKER_MEMCG_AWARE) + unregister_memcg_shrinker(shrinker); down_write(&shrinker_rwsem); list_del(&shrinker->list); up_write(&shrinker_rwsem); -- cgit v1.2.3-55-g7522