From 14b146b688ad9593f5eee93d51a34d09a47e50b5 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 27 Jul 2022 10:30:41 +0100 Subject: io_uring: notification completion optimisation We want to use all optimisations that we have for io_uring requests like completion batching, memory caching and more but for zc notifications. Fortunately, notification perfectly fit the request model so we can overlay them onto struct io_kiocb and use all the infratructure. Most of the fields of struct io_notif natively fits into io_kiocb, so we replace struct io_notif with struct io_kiocb carrying struct io_notif_data in the cmd cache line. Then we adapt io_alloc_notif() to use io_alloc_req()/io_alloc_req_refill(), and kill leftovers of hand coded caching. __io_notif_complete_tw() is converted to use io_uring's tw infra. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/9e010125175e80baf51f0ca63bdc7cc6a4a9fa56.1658913593.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/notif.c | 159 ++++++++++++++++++------------------------------------- 1 file changed, 52 insertions(+), 107 deletions(-) (limited to 'io_uring/notif.c') diff --git a/io_uring/notif.c b/io_uring/notif.c index e986a0ed958c..b5f989dff9de 100644 --- a/io_uring/notif.c +++ b/io_uring/notif.c @@ -9,140 +9,79 @@ #include "notif.h" #include "rsrc.h" -static void __io_notif_complete_tw(struct callback_head *cb) +static void __io_notif_complete_tw(struct io_kiocb *notif, bool *locked) { - struct io_notif *notif = container_of(cb, struct io_notif, task_work); - struct io_rsrc_node *rsrc_node = notif->rsrc_node; + struct io_notif_data *nd = io_notif_to_data(notif); struct io_ring_ctx *ctx = notif->ctx; - if (notif->account_pages && ctx->user) { - __io_unaccount_mem(ctx->user, notif->account_pages); - notif->account_pages = 0; + if (nd->account_pages && ctx->user) { + __io_unaccount_mem(ctx->user, nd->account_pages); + nd->account_pages = 0; } - if (likely(notif->task)) { - io_put_task(notif->task, 1); - notif->task = NULL; - } - - io_cq_lock(ctx); - io_fill_cqe_aux(ctx, notif->tag, 0, notif->seq, true); - - list_add(¬if->cache_node, &ctx->notif_list_locked); - ctx->notif_locked_nr++; - io_cq_unlock_post(ctx); - - io_rsrc_put_node(rsrc_node, 1); - percpu_ref_put(&ctx->refs); + io_req_task_complete(notif, locked); } -static inline void io_notif_complete(struct io_notif *notif) +static inline void io_notif_complete(struct io_kiocb *notif) + __must_hold(¬if->ctx->uring_lock) { - __io_notif_complete_tw(¬if->task_work); -} - -static void io_notif_complete_wq(struct work_struct *work) -{ - struct io_notif *notif = container_of(work, struct io_notif, commit_work); + bool locked = true; - io_notif_complete(notif); + __io_notif_complete_tw(notif, &locked); } static void io_uring_tx_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg, bool success) { - struct io_notif *notif = container_of(uarg, struct io_notif, uarg); - - if (!refcount_dec_and_test(&uarg->refcnt)) - return; - - if (likely(notif->task)) { - init_task_work(¬if->task_work, __io_notif_complete_tw); - if (likely(!task_work_add(notif->task, ¬if->task_work, - TWA_SIGNAL))) - return; - } - - INIT_WORK(¬if->commit_work, io_notif_complete_wq); - queue_work(system_unbound_wq, ¬if->commit_work); -} - -static void io_notif_splice_cached(struct io_ring_ctx *ctx) - __must_hold(&ctx->uring_lock) -{ - spin_lock(&ctx->completion_lock); - list_splice_init(&ctx->notif_list_locked, &ctx->notif_list); - ctx->notif_locked_nr = 0; - spin_unlock(&ctx->completion_lock); -} - -void io_notif_cache_purge(struct io_ring_ctx *ctx) - __must_hold(&ctx->uring_lock) -{ - io_notif_splice_cached(ctx); + struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg); + struct io_kiocb *notif = cmd_to_io_kiocb(nd); - while (!list_empty(&ctx->notif_list)) { - struct io_notif *notif = list_first_entry(&ctx->notif_list, - struct io_notif, cache_node); - - list_del(¬if->cache_node); - kfree(notif); + if (refcount_dec_and_test(&uarg->refcnt)) { + notif->io_task_work.func = __io_notif_complete_tw; + io_req_task_work_add(notif); } } -static inline bool io_notif_has_cached(struct io_ring_ctx *ctx) - __must_hold(&ctx->uring_lock) -{ - if (likely(!list_empty(&ctx->notif_list))) - return true; - if (data_race(READ_ONCE(ctx->notif_locked_nr) <= IO_NOTIF_SPLICE_BATCH)) - return false; - io_notif_splice_cached(ctx); - return !list_empty(&ctx->notif_list); -} - -struct io_notif *io_alloc_notif(struct io_ring_ctx *ctx, +struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx, struct io_notif_slot *slot) __must_hold(&ctx->uring_lock) { - struct io_notif *notif; - - if (likely(io_notif_has_cached(ctx))) { - notif = list_first_entry(&ctx->notif_list, - struct io_notif, cache_node); - list_del(¬if->cache_node); - } else { - notif = kzalloc(sizeof(*notif), GFP_ATOMIC | __GFP_ACCOUNT); - if (!notif) - return NULL; - /* pre-initialise some fields */ - notif->ctx = ctx; - notif->uarg.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN; - notif->uarg.callback = io_uring_tx_zerocopy_callback; - notif->account_pages = 0; - } - - notif->seq = slot->seq++; - notif->tag = slot->tag; + struct io_kiocb *notif; + struct io_notif_data *nd; + + if (unlikely(!io_alloc_req_refill(ctx))) + return NULL; + notif = io_alloc_req(ctx); + notif->opcode = IORING_OP_NOP; + notif->flags = 0; + notif->file = NULL; + notif->task = current; + io_get_task_refs(1); + notif->rsrc_node = NULL; + io_req_set_rsrc_node(notif, ctx, 0); + notif->cqe.user_data = slot->tag; + notif->cqe.flags = slot->seq++; + notif->cqe.res = 0; + + nd = io_notif_to_data(notif); + nd->account_pages = 0; + nd->uarg.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN; + nd->uarg.callback = io_uring_tx_zerocopy_callback; /* master ref owned by io_notif_slot, will be dropped on flush */ - refcount_set(¬if->uarg.refcnt, 1); - percpu_ref_get(&ctx->refs); - notif->rsrc_node = ctx->rsrc_node; - io_charge_rsrc_node(ctx); + refcount_set(&nd->uarg.refcnt, 1); return notif; } void io_notif_slot_flush(struct io_notif_slot *slot) __must_hold(&ctx->uring_lock) { - struct io_notif *notif = slot->notif; + struct io_kiocb *notif = slot->notif; + struct io_notif_data *nd = io_notif_to_data(notif); slot->notif = NULL; - if (WARN_ON_ONCE(in_interrupt())) - return; /* drop slot's master ref */ - if (refcount_dec_and_test(¬if->uarg.refcnt)) + if (refcount_dec_and_test(&nd->uarg.refcnt)) io_notif_complete(notif); } @@ -156,18 +95,22 @@ __cold int io_notif_unregister(struct io_ring_ctx *ctx) for (i = 0; i < ctx->nr_notif_slots; i++) { struct io_notif_slot *slot = &ctx->notif_slots[i]; + struct io_kiocb *notif = slot->notif; + struct io_notif_data *nd; - if (!slot->notif) + if (!notif) + continue; + nd = io_kiocb_to_cmd(notif); + slot->notif = NULL; + if (!refcount_dec_and_test(&nd->uarg.refcnt)) continue; - if (WARN_ON_ONCE(slot->notif->task)) - slot->notif->task = NULL; - io_notif_slot_flush(slot); + notif->io_task_work.func = __io_notif_complete_tw; + io_req_task_work_add(notif); } kvfree(ctx->notif_slots); ctx->notif_slots = NULL; ctx->nr_notif_slots = 0; - io_notif_cache_purge(ctx); return 0; } @@ -180,6 +123,8 @@ __cold int io_notif_register(struct io_ring_ctx *ctx, struct io_uring_notification_register reg; unsigned i; + BUILD_BUG_ON(sizeof(struct io_notif_data) > 64); + if (ctx->nr_notif_slots) return -EBUSY; if (size != sizeof(reg)) -- cgit v1.2.3