diff options
| author | Jens Axboe <axboe@kernel.dk> | 2022-07-07 22:20:54 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-07-25 02:39:17 +0200 |
| commit | 9731bc9855dc169f27433fef3c4d0ff3496c512d (patch) | |
| tree | b28facb6c0ee4796e2787a5c736231a73520993f | |
| parent | io_uring: add abstraction around apoll cache (diff) | |
| download | linux-9731bc9855dc169f27433fef3c4d0ff3496c512d.tar.xz linux-9731bc9855dc169f27433fef3c4d0ff3496c512d.zip | |
io_uring: impose max limit on apoll cache
Caches like this tend to grow to the peak size, and then never get any
smaller. Impose a max limit on the size, to prevent it from growing too
big.
A somewhat randomly chosen 512 is the max size we'll allow the cache
to get. If a batch of frees come in and would bring it over that, we
simply start kfree'ing the surplus.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | include/linux/io_uring_types.h | 1 | ||||
| -rw-r--r-- | io_uring/alloc_cache.h | 16 | ||||
| -rw-r--r-- | io_uring/io_uring.c | 3 |
3 files changed, 17 insertions, 3 deletions
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index b548da03b563..bf8f95332eda 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -160,6 +160,7 @@ struct io_ev_fd { struct io_alloc_cache { struct hlist_head list; + unsigned int nr_cached; }; struct io_ring_ctx { diff --git a/io_uring/alloc_cache.h b/io_uring/alloc_cache.h index 98f2374c37c7..729793ae9712 100644 --- a/io_uring/alloc_cache.h +++ b/io_uring/alloc_cache.h @@ -1,14 +1,24 @@ #ifndef IOU_ALLOC_CACHE_H #define IOU_ALLOC_CACHE_H +/* + * Don't allow the cache to grow beyond this size. + */ +#define IO_ALLOC_CACHE_MAX 512 + struct io_cache_entry { struct hlist_node node; }; -static inline void io_alloc_cache_put(struct io_alloc_cache *cache, +static inline bool io_alloc_cache_put(struct io_alloc_cache *cache, struct io_cache_entry *entry) { - hlist_add_head(&entry->node, &cache->list); + if (cache->nr_cached < IO_ALLOC_CACHE_MAX) { + cache->nr_cached++; + hlist_add_head(&entry->node, &cache->list); + return true; + } + return false; } static inline struct io_cache_entry *io_alloc_cache_get(struct io_alloc_cache *cache) @@ -26,6 +36,7 @@ static inline struct io_cache_entry *io_alloc_cache_get(struct io_alloc_cache *c static inline void io_alloc_cache_init(struct io_alloc_cache *cache) { INIT_HLIST_HEAD(&cache->list); + cache->nr_cached = 0; } static inline void io_alloc_cache_free(struct io_alloc_cache *cache, @@ -37,5 +48,6 @@ static inline void io_alloc_cache_free(struct io_alloc_cache *cache, hlist_del(node); free(container_of(node, struct io_cache_entry, node)); } + cache->nr_cached = 0; } #endif diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index a360a3d390c6..c9c23e459766 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1181,7 +1181,8 @@ void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node) if (apoll->double_poll) kfree(apoll->double_poll); - io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache); + if (!io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache)) + kfree(apoll); req->flags &= ~REQ_F_POLLED; } if (req->flags & IO_REQ_LINK_FLAGS) |