[for-next,15/25] io_uring: switch cancel_hash to use per entry spinlock

Message ID	2fedbcc47d82f5c98ccf94b6bdcada14f9ebdd59.1655209709.git.asml.silence@gmail.com (mailing list archive)
State	New
Headers	show Return-Path: <io-uring-owner@kernel.org> From: Pavel Begunkov <asml.silence@gmail.com> To: io-uring@vger.kernel.org Cc: Jens Axboe <axboe@kernel.dk>, asml.silence@gmail.com, Hao Xu <howeyxu@tencent.com> Subject: [PATCH for-next 15/25] io_uring: switch cancel_hash to use per entry spinlock Date: Tue, 14 Jun 2022 13:29:53 +0100 Message-Id: <2fedbcc47d82f5c98ccf94b6bdcada14f9ebdd59.1655209709.git.asml.silence@gmail.com> In-Reply-To: <cover.1655209709.git.asml.silence@gmail.com> References: <cover.1655209709.git.asml.silence@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	5.20 cleanups and poll optimisations \| expand [for-next,00/25] 5.20 cleanups and poll optimisations [for-next,01/25] io_uring: make reg buf init consistent [for-next,02/25] io_uring: move defer_list to slow data [for-next,03/25] io_uring: better caching for ctx timeout fields [for-next,04/25] io_uring: refactor ctx slow data placement [for-next,05/25] io_uring: move cancel_seq out of io-wq [for-next,06/25] io_uring: move small helpers to headers [for-next,07/25] io_uring: inline ->registered_rings [for-next,08/25] io_uring: don't set REQ_F_COMPLETE_INLINE in tw [for-next,09/25] io_uring: never defer-complete multi-apoll [for-next,10/25] io_uring: kill REQ_F_COMPLETE_INLINE [for-next,11/25] io_uring: refactor io_req_task_complete() [for-next,12/25] io_uring: don't inline io_put_kbuf [for-next,13/25] io_uring: remove check_cq checking from hot paths [for-next,14/25] io_uring: poll: remove unnecessary req->ref set [for-next,15/25] io_uring: switch cancel_hash to use per entry spinlock [for-next,16/25] io_uring: pass poll_find lock back [for-next,17/25] io_uring: clean up io_try_cancel [for-next,18/25] io_uring: limit number hash buckets [for-next,19/25] io_uring: clean up io_ring_ctx_alloc [for-next,20/25] io_uring: use state completion infra for poll reqs [for-next,21/25] io_uring: add IORING_SETUP_SINGLE_ISSUER [for-next,22/25] io_uring: pass hash table into poll_find [for-next,23/25] io_uring: introduce a struct for hash table [for-next,24/25] io_uring: propagate locking state to poll cancel [for-next,25/25] io_uring: mutex locked poll hashing

diff --git a/io_uring/cancel.c b/io_uring/cancel.c index 2e72231882b7..54a5e0a86b61 100644 --- a/io_uring/cancel.c +++ b/io_uring/cancel.c @@ -93,14 +93,14 @@ int io_try_cancel(struct io_kiocb *req, struct io_cancel_data *cd) if (!ret) return 0; - spin_lock(&ctx->completion_lock); ret = io_poll_cancel(ctx, cd); if (ret != -ENOENT) goto out; + spin_lock(&ctx->completion_lock); if (!(cd->flags & IORING_ASYNC_CANCEL_FD)) ret = io_timeout_cancel(ctx, cd); -out: spin_unlock(&ctx->completion_lock); +out: return ret; } @@ -192,3 +192,13 @@ int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags) io_req_set_res(req, ret, 0); return IOU_OK; } + +void init_hash_table(struct io_hash_bucket *hash_table, unsigned size) +{ + unsigned int i; + + for (i = 0; i < size; i++) { + spin_lock_init(&hash_table[i].lock); + INIT_HLIST_HEAD(&hash_table[i].list); + } +} diff --git a/io_uring/cancel.h b/io_uring/cancel.h index 4f35d8696325..556a7dcf160e 100644 --- a/io_uring/cancel.h +++ b/io_uring/cancel.h @@ -4,3 +4,9 @@ int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags); int io_try_cancel(struct io_kiocb *req, struct io_cancel_data *cd); +void init_hash_table(struct io_hash_bucket *hash_table, unsigned size); + +struct io_hash_bucket { + spinlock_t lock; + struct hlist_head list; +} ____cacheline_aligned_in_smp; diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c index fcedde4b4b1e..f941c73f5502 100644 --- a/io_uring/fdinfo.c +++ b/io_uring/fdinfo.c @@ -13,6 +13,7 @@ #include "io_uring.h" #include "sqpoll.h" #include "fdinfo.h" +#include "cancel.h" #ifdef CONFIG_PROC_FS static __cold int io_uring_show_cred(struct seq_file *m, unsigned int id, @@ -157,17 +158,19 @@ static __cold void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, mutex_unlock(&ctx->uring_lock); seq_puts(m, "PollList:\n"); - spin_lock(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { - struct hlist_head *list = &ctx->cancel_hash[i]; + struct io_hash_bucket *hb = &ctx->cancel_hash[i]; struct io_kiocb *req; - hlist_for_each_entry(req, list, hash_node) + spin_lock(&hb->lock); + hlist_for_each_entry(req, &hb->list, hash_node) seq_printf(m, " op=%d, task_works=%d\n", req->opcode, task_work_pending(req->task)); + spin_unlock(&hb->lock); } seq_puts(m, "CqOverflowList:\n"); + spin_lock(&ctx->completion_lock); list_for_each_entry(ocqe, &ctx->cq_overflow_list, list) { struct io_uring_cqe *cqe = &ocqe->cqe; diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index bd2aab895e29..4e0f60ffc975 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -717,11 +717,13 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) if (hash_bits <= 0) hash_bits = 1; ctx->cancel_hash_bits = hash_bits; - ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head), - GFP_KERNEL); + ctx->cancel_hash = + kmalloc((1U << hash_bits) * sizeof(struct io_hash_bucket), + GFP_KERNEL); if (!ctx->cancel_hash) goto err; - __hash_init(ctx->cancel_hash, 1U << hash_bits); + + init_hash_table(ctx->cancel_hash, 1U << hash_bits); ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL); if (!ctx->dummy_ubuf) diff --git a/io_uring/io_uring_types.h b/io_uring/io_uring_types.h index 3cf06f4a4d2e..0dd3ab7eec4c 100644 --- a/io_uring/io_uring_types.h +++ b/io_uring/io_uring_types.h @@ -222,7 +222,7 @@ struct io_ring_ctx { * manipulate the list, hence no extra locking is needed there. */ struct io_wq_work_list iopoll_list; - struct hlist_head *cancel_hash; + struct io_hash_bucket *cancel_hash; unsigned cancel_hash_bits; bool poll_multi_queue; diff --git a/io_uring/poll.c b/io_uring/poll.c index be3dd77fa21c..ab4be4173cf3 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -19,6 +19,7 @@ #include "opdef.h" #include "kbuf.h" #include "poll.h" +#include "cancel.h" struct io_poll_update { struct file *file; @@ -73,10 +74,22 @@ static struct io_poll *io_poll_get_single(struct io_kiocb *req) static void io_poll_req_insert(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; - struct hlist_head *list; + u32 index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits); + struct io_hash_bucket *hb = &ctx->cancel_hash[index]; - list = &ctx->cancel_hash[hash_long(req->cqe.user_data, ctx->cancel_hash_bits)]; - hlist_add_head(&req->hash_node, list); + spin_lock(&hb->lock); + hlist_add_head(&req->hash_node, &hb->list); + spin_unlock(&hb->lock); +} + +static void io_poll_req_delete(struct io_kiocb *req, struct io_ring_ctx *ctx) +{ + u32 index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits); + spinlock_t *lock = &ctx->cancel_hash[index].lock; + + spin_lock(lock); + hash_del(&req->hash_node); + spin_unlock(lock); } static void io_init_poll_iocb(struct io_poll *poll, __poll_t events, @@ -220,8 +233,8 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) } io_poll_remove_entries(req); + io_poll_req_delete(req, ctx); spin_lock(&ctx->completion_lock); - hash_del(&req->hash_node); req->cqe.flags = 0; __io_req_complete_post(req); io_commit_cqring(ctx); @@ -231,7 +244,6 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) static void io_apoll_task_func(struct io_kiocb *req, bool *locked) { - struct io_ring_ctx *ctx = req->ctx; int ret; ret = io_poll_check_events(req, locked); @@ -239,9 +251,7 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) return; io_poll_remove_entries(req); - spin_lock(&ctx->completion_lock); - hash_del(&req->hash_node); - spin_unlock(&ctx->completion_lock); + io_poll_req_delete(req, req->ctx); if (!ret) io_req_task_submit(req, locked); @@ -435,9 +445,7 @@ static int __io_arm_poll_handler(struct io_kiocb *req, return 0; } - spin_lock(&ctx->completion_lock); io_poll_req_insert(req); - spin_unlock(&ctx->completion_lock); if (mask && (poll->events & EPOLLET)) { /* can't multishot if failed, just queue the event we've got */ @@ -534,32 +542,31 @@ __cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk, bool found = false; int i; - spin_lock(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { - struct hlist_head *list; + struct io_hash_bucket *hb = &ctx->cancel_hash[i]; - list = &ctx->cancel_hash[i]; - hlist_for_each_entry_safe(req, tmp, list, hash_node) { + spin_lock(&hb->lock); + hlist_for_each_entry_safe(req, tmp, &hb->list, hash_node) { if (io_match_task_safe(req, tsk, cancel_all)) { hlist_del_init(&req->hash_node); io_poll_cancel_req(req); found = true; } } + spin_unlock(&hb->lock); } - spin_unlock(&ctx->completion_lock); return found; } static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, struct io_cancel_data *cd) - __must_hold(&ctx->completion_lock) { - struct hlist_head *list; struct io_kiocb *req; + u32 index = hash_long(cd->data, ctx->cancel_hash_bits); + struct io_hash_bucket *hb = &ctx->cancel_hash[index]; - list = &ctx->cancel_hash[hash_long(cd->data, ctx->cancel_hash_bits)]; - hlist_for_each_entry(req, list, hash_node) { + spin_lock(&hb->lock); + hlist_for_each_entry(req, &hb->list, hash_node) { if (cd->data != req->cqe.user_data) continue; if (poll_only && req->opcode != IORING_OP_POLL_ADD) @@ -571,21 +578,21 @@ static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, } return req; } + spin_unlock(&hb->lock); return NULL; } static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx, struct io_cancel_data *cd) - __must_hold(&ctx->completion_lock) { struct io_kiocb *req; int i; for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { - struct hlist_head *list; + struct io_hash_bucket *hb = &ctx->cancel_hash[i]; - list = &ctx->cancel_hash[i]; - hlist_for_each_entry(req, list, hash_node) { + spin_lock(&hb->lock); + hlist_for_each_entry(req, &hb->list, hash_node) { if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) && req->file != cd->file) continue; @@ -594,12 +601,12 @@ static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx, req->cancel_seq = cd->seq; return req; } + spin_unlock(&hb->lock); } return NULL; } static bool io_poll_disarm(struct io_kiocb *req) - __must_hold(&ctx->completion_lock) { if (!io_poll_get_ownership(req)) return false; @@ -609,17 +616,23 @@ static bool io_poll_disarm(struct io_kiocb *req) } int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd) - __must_hold(&ctx->completion_lock) { struct io_kiocb *req; + u32 index; + spinlock_t *lock; if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY)) req = io_poll_file_find(ctx, cd); else req = io_poll_find(ctx, false, cd); - if (!req) + if (!req) { return -ENOENT; + } else { + index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits); + lock = &ctx->cancel_hash[index].lock; + } io_poll_cancel_req(req); + spin_unlock(lock); return 0; } @@ -713,18 +726,23 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags) struct io_poll_update *poll_update = io_kiocb_to_cmd(req); struct io_cancel_data cd = { .data = poll_update->old_user_data, }; struct io_ring_ctx *ctx = req->ctx; + u32 index = hash_long(cd.data, ctx->cancel_hash_bits); + spinlock_t *lock = &ctx->cancel_hash[index].lock; struct io_kiocb *preq; int ret2, ret = 0; bool locked; - spin_lock(&ctx->completion_lock); preq = io_poll_find(ctx, true, &cd); - if (!preq || !io_poll_disarm(preq)) { - spin_unlock(&ctx->completion_lock); - ret = preq ? -EALREADY : -ENOENT; + if (!preq) { + ret = -ENOENT; + goto out; + } + ret2 = io_poll_disarm(preq); + spin_unlock(lock); + if (!ret2) { + ret = -EALREADY; goto out; } - spin_unlock(&ctx->completion_lock); if (poll_update->update_events || poll_update->update_user_data) { /* only mask one event flags, keep behavior flags */

[for-next,15/25] io_uring: switch cancel_hash to use per entry spinlock

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