From e941894eae31b52f0fd9bdb3ce20620afa152f45 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 19 Feb 2021 12:33:30 -0700 Subject: io-wq: make buffered file write hashed work map per-ctx Before the io-wq thread change, we maintained a hash work map and lock per-node per-ring. That wasn't ideal, as we really wanted it to be per ring. But now that we have per-task workers, the hash map ends up being just per-task. That'll work just fine for the normal case of having one task use a ring, but if you share the ring between tasks, then it's considerably worse than it was before. Make the hash map per ctx instead, which provides full per-ctx buffered write serialization on hashed writes. Signed-off-by: Jens Axboe --- fs/io_uring.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index 0a435a6f265a..fbc85afa9a87 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -360,6 +360,9 @@ struct io_ring_ctx { unsigned cached_cq_overflow; unsigned long sq_check_overflow; + /* hashed buffered write serialization */ + struct io_wq_hash *hash_map; + struct list_head defer_list; struct list_head timeout_list; struct list_head cq_overflow_list; @@ -454,6 +457,8 @@ struct io_ring_ctx { /* exit task_work */ struct callback_head *exit_task_work; + struct wait_queue_head hash_wait; + /* Keep this last, we don't need it for the fast path */ struct work_struct exit_work; }; @@ -7763,9 +7768,21 @@ static struct io_wq_work *io_free_work(struct io_wq_work *work) static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx) { + struct io_wq_hash *hash; struct io_wq_data data; unsigned int concurrency; + hash = ctx->hash_map; + if (!hash) { + hash = kzalloc(sizeof(*hash), GFP_KERNEL); + if (!hash) + return ERR_PTR(-ENOMEM); + refcount_set(&hash->refs, 1); + init_waitqueue_head(&hash->wait); + ctx->hash_map = hash; + } + + data.hash = hash; data.free_work = io_free_work; data.do_work = io_wq_submit_work; @@ -8405,6 +8422,8 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) percpu_ref_exit(&ctx->refs); free_uid(ctx->user); io_req_caches_free(ctx, NULL); + if (ctx->hash_map) + io_wq_put_hash(ctx->hash_map); kfree(ctx->cancel_hash); kfree(ctx); } -- cgit v1.2.3