From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83521C6FD1D for ; Mon, 20 Mar 2023 20:43:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229677AbjCTUnv (ORCPT ); Mon, 20 Mar 2023 16:43:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229967AbjCTUnt (ORCPT ); Mon, 20 Mar 2023 16:43:49 -0400 Received: from mail-io1-xd30.google.com (mail-io1-xd30.google.com [IPv6:2607:f8b0:4864:20::d30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BF52E1A0 for ; Mon, 20 Mar 2023 13:43:00 -0700 (PDT) Received: by mail-io1-xd30.google.com with SMTP id bf15so6032926iob.7 for ; Mon, 20 Mar 2023 13:43:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1679344978; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=qB89k+mp21XHp6F57o2ThBPOzJaPAjgc0F9LWJsVUoc=; b=iJ25y+acw88tHWJ6mHmb/UfMa0qgt0aF/oC3h3paFs95VnquXmWinHDK9GZUqq2NKq 41KLKEFYqiggRUQMv0qTUWc3N5lQ7lvABa0bb2r/+1AN7hRVmzATvM/8T7D6WVMNrOs9 +fPoMnywXk8EVAGi0r9B6hVdPpzh7jYCeiRGUOljcA7MXlkngVmqoVhZfgxqkdL6b5+4 uTPhtM7dRZNdth3BhxiBKasMwjsIu4xhq7CW4KPOu+yRGsIb6UUMlMRmtMDPPF0UIzLU +scXAsHt4AaxV1AaSw4OcakY0qnfZGgdfNt8gCQdAEhBYu4FNXbGJZr0WTfsVUSszXT2 cv9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679344978; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=qB89k+mp21XHp6F57o2ThBPOzJaPAjgc0F9LWJsVUoc=; b=ezkhSDp2Xv6h35zIxwdW4qzpoHaKwFhVZJPqwzJnYwkSO7ZoFl4GxVdLZ/alnWOkhL PgIpcNCOXX5Pg3K2M1Z0twXQG4ZKEjZbfDXFWtxzfkNz7b4bRnj8eRJxuSUvfljxcMs+ a4TSb6TLVoYVf1fvi7phUVQNMf17Y0PCNMcxovozBtXnsDo8mGbCAJK1sVW+o5y+xJ5e zVuWyQn05dRMudURebJvh7GT4KpN36uUJ4pS/4z3RswXcOKDAoR/VoWXCZS+CluVeVeO aa6d6Iedkmfol6csiOCYEqZ+JcyJveAMxQY7hUzqsFZPiMzj2+jiVji6lqEJZ8XyppeV yVTA== X-Gm-Message-State: AO0yUKWd195mjxlt3kpzqV46bkF++0rjFoTh/goR0BZAktMsgDi2s9/q T6cxvQkRBRKO1WqCxvaWa1dZyQ== X-Google-Smtp-Source: AK7set/RWp1iOrNIifkeZgjD4ctqTtlAeIxoFqQ4iAMBj9dmxQ269K0+cDHE/rCjsTiNurj1yRFe2A== X-Received: by 2002:a6b:5f09:0:b0:74e:5fba:d5df with SMTP id t9-20020a6b5f09000000b0074e5fbad5dfmr442709iob.0.1679344977892; Mon, 20 Mar 2023 13:42:57 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id p5-20020a056638190500b003ff471861a4sm3503494jal.90.2023.03.20.13.42.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Mar 2023 13:42:57 -0700 (PDT) Message-ID: Date: Mon, 20 Mar 2023 14:42:56 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH] io_uring/uring_cmd: push IRQ based completions through task_work Content-Language: en-US From: Jens Axboe To: Kanchan Joshi Cc: io-uring , Kanchan Joshi References: <4b4e3526-e6b5-73dd-c6fb-f7ddccf19f33@kernel.dk> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/20/23 2:03?PM, Jens Axboe wrote: > On 3/20/23 9:06?AM, Kanchan Joshi wrote: >> On Sun, Mar 19, 2023 at 8:51?PM Jens Axboe wrote: >>> >>> This is similar to what we do on the non-passthrough read/write side, >>> and helps take advantage of the completion batching we can do when we >>> post CQEs via task_work. On top of that, this avoids a uring_lock >>> grab/drop for every completion. >>> >>> In the normal peak IRQ based testing, this increases performance in >>> my testing from ~75M to ~77M IOPS, or an increase of 2-3%. >>> >>> Signed-off-by: Jens Axboe >>> >>> --- >>> >>> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >>> index 2e4c483075d3..b4fba5f0ab0d 100644 >>> --- a/io_uring/uring_cmd.c >>> +++ b/io_uring/uring_cmd.c >>> @@ -45,18 +45,21 @@ static inline void io_req_set_cqe32_extra(struct io_kiocb *req, >>> void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2) >>> { >>> struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); >>> + struct io_ring_ctx *ctx = req->ctx; >>> >>> if (ret < 0) >>> req_set_fail(req); >>> >>> io_req_set_res(req, ret, 0); >>> - if (req->ctx->flags & IORING_SETUP_CQE32) >>> + if (ctx->flags & IORING_SETUP_CQE32) >>> io_req_set_cqe32_extra(req, res2, 0); >>> - if (req->ctx->flags & IORING_SETUP_IOPOLL) >>> + if (ctx->flags & IORING_SETUP_IOPOLL) { >>> /* order with io_iopoll_req_issued() checking ->iopoll_complete */ >>> smp_store_release(&req->iopoll_completed, 1); >>> - else >>> - io_req_complete_post(req, 0); >>> + return; >>> + } >>> + req->io_task_work.func = io_req_task_complete; >>> + io_req_task_work_add(req); >>> } >> >> Since io_uring_cmd_done itself would be executing in task-work often >> (always in case of nvme), can this be further optimized by doing >> directly what this new task-work (that is being set up here) would >> have done? >> Something like below on top of your patch - >> >> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >> index e1929f6e5a24..7a764e04f309 100644 >> --- a/io_uring/uring_cmd.c >> +++ b/io_uring/uring_cmd.c >> @@ -58,8 +58,12 @@ void io_uring_cmd_done(struct io_uring_cmd *ioucmd, >> ssize_t ret, ssize_t res2) >> smp_store_release(&req->iopoll_completed, 1); >> return; >> } >> - req->io_task_work.func = io_req_task_complete; >> - io_req_task_work_add(req); >> + if (in_task()) { >> + io_req_complete_defer(req); >> + } else { >> + req->io_task_work.func = io_req_task_complete; >> + io_req_task_work_add(req); >> + } >> } >> EXPORT_SYMBOL_GPL(io_uring_cmd_done); > > Good point, though I do think we should rework to pass in the flags > instead. I'll take a look. Something like this, totally untested... And this may be more interesting than it would appear, because the current: io_req_complete_post(req, 0); in io_uring_cmd_done() is passing in that it has the CQ ring locked, but that does not look like it's guaranteed? So this is more of a correctness thing first and foremost, more so than an optimization. Hmm? diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index d1d1c8d606c8..6615986e976c 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -715,7 +715,7 @@ static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io, } } -static void ubq_complete_io_cmd(struct ublk_io *io, int res) +static void ubq_complete_io_cmd(struct ublk_io *io, int res, unsigned flags) { /* mark this cmd owned by ublksrv */ io->flags |= UBLK_IO_FLAG_OWNED_BY_SRV; @@ -727,7 +727,7 @@ static void ubq_complete_io_cmd(struct ublk_io *io, int res) io->flags &= ~UBLK_IO_FLAG_ACTIVE; /* tell ublksrv one io request is coming */ - io_uring_cmd_done(io->cmd, res, 0); + io_uring_cmd_done(io->cmd, res, 0, flags); } #define UBLK_REQUEUE_DELAY_MS 3 @@ -744,7 +744,7 @@ static inline void __ublk_abort_rq(struct ublk_queue *ubq, mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0); } -static inline void __ublk_rq_task_work(struct request *req) +static inline void __ublk_rq_task_work(struct request *req, unsigned issue_flags) { struct ublk_queue *ubq = req->mq_hctx->driver_data; int tag = req->tag; @@ -782,7 +782,7 @@ static inline void __ublk_rq_task_work(struct request *req) pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n", __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags); - ubq_complete_io_cmd(io, UBLK_IO_RES_NEED_GET_DATA); + ubq_complete_io_cmd(io, UBLK_IO_RES_NEED_GET_DATA, issue_flags); return; } /* @@ -820,17 +820,17 @@ static inline void __ublk_rq_task_work(struct request *req) mapped_bytes >> 9; } - ubq_complete_io_cmd(io, UBLK_IO_RES_OK); + ubq_complete_io_cmd(io, UBLK_IO_RES_OK, issue_flags); } -static inline void ublk_forward_io_cmds(struct ublk_queue *ubq) +static inline void ublk_forward_io_cmds(struct ublk_queue *ubq, unsigned flags) { struct llist_node *io_cmds = llist_del_all(&ubq->io_cmds); struct ublk_rq_data *data, *tmp; io_cmds = llist_reverse_order(io_cmds); llist_for_each_entry_safe(data, tmp, io_cmds, node) - __ublk_rq_task_work(blk_mq_rq_from_pdu(data)); + __ublk_rq_task_work(blk_mq_rq_from_pdu(data), flags); } static inline void ublk_abort_io_cmds(struct ublk_queue *ubq) @@ -842,12 +842,12 @@ static inline void ublk_abort_io_cmds(struct ublk_queue *ubq) __ublk_abort_rq(ubq, blk_mq_rq_from_pdu(data)); } -static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd) +static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd, unsigned issue_flags) { struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd); struct ublk_queue *ubq = pdu->ubq; - ublk_forward_io_cmds(ubq); + ublk_forward_io_cmds(ubq, issue_flags); } static void ublk_rq_task_work_fn(struct callback_head *work) @@ -856,8 +856,9 @@ static void ublk_rq_task_work_fn(struct callback_head *work) struct ublk_rq_data, work); struct request *req = blk_mq_rq_from_pdu(data); struct ublk_queue *ubq = req->mq_hctx->driver_data; + unsigned issue_flags = IO_URING_F_UNLOCKED; - ublk_forward_io_cmds(ubq); + ublk_forward_io_cmds(ubq, issue_flags); } static void ublk_queue_cmd(struct ublk_queue *ubq, struct request *rq) @@ -1111,7 +1112,8 @@ static void ublk_cancel_queue(struct ublk_queue *ubq) struct ublk_io *io = &ubq->ios[i]; if (io->flags & UBLK_IO_FLAG_ACTIVE) - io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0); + io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0, + IO_URING_F_UNLOCKED); } /* all io commands are canceled */ @@ -1351,7 +1353,7 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) return -EIOCBQUEUED; out: - io_uring_cmd_done(cmd, ret, 0); + io_uring_cmd_done(cmd, ret, 0, issue_flags); pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n", __func__, cmd_op, tag, ret, io->flags); return -EIOCBQUEUED; @@ -2233,7 +2235,7 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, if (ub) ublk_put_device(ub); out: - io_uring_cmd_done(cmd, ret, 0); + io_uring_cmd_done(cmd, ret, 0, issue_flags); pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n", __func__, ret, cmd->cmd_op, header->dev_id, header->queue_id); return -EIOCBQUEUED; diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c index 723e7d5b778f..fd547b81d1d2 100644 --- a/drivers/nvme/host/ioctl.c +++ b/drivers/nvme/host/ioctl.c @@ -464,7 +464,7 @@ static inline struct nvme_uring_cmd_pdu *nvme_uring_cmd_pdu( return (struct nvme_uring_cmd_pdu *)&ioucmd->pdu; } -static void nvme_uring_task_meta_cb(struct io_uring_cmd *ioucmd) +static void nvme_uring_task_meta_cb(struct io_uring_cmd *ioucmd, unsigned flags) { struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd); struct request *req = pdu->req; @@ -485,17 +485,17 @@ static void nvme_uring_task_meta_cb(struct io_uring_cmd *ioucmd) blk_rq_unmap_user(req->bio); blk_mq_free_request(req); - io_uring_cmd_done(ioucmd, status, result); + io_uring_cmd_done(ioucmd, status, result, flags); } -static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd) +static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd, unsigned flags) { struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd); if (pdu->bio) blk_rq_unmap_user(pdu->bio); - io_uring_cmd_done(ioucmd, pdu->nvme_status, pdu->u.result); + io_uring_cmd_done(ioucmd, pdu->nvme_status, pdu->u.result, flags); } static enum rq_end_io_ret nvme_uring_cmd_end_io(struct request *req, @@ -517,7 +517,7 @@ static enum rq_end_io_ret nvme_uring_cmd_end_io(struct request *req, * Otherwise, move the completion to task work. */ if (cookie != NULL && blk_rq_is_poll(req)) - nvme_uring_task_cb(ioucmd); + nvme_uring_task_cb(ioucmd, IO_URING_F_UNLOCKED); else io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb); @@ -539,7 +539,7 @@ static enum rq_end_io_ret nvme_uring_cmd_end_io_meta(struct request *req, * Otherwise, move the completion to task work. */ if (cookie != NULL && blk_rq_is_poll(req)) - nvme_uring_task_meta_cb(ioucmd); + nvme_uring_task_meta_cb(ioucmd, IO_URING_F_UNLOCKED); else io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_meta_cb); diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h index 934e5dd4ccc0..562453edff69 100644 --- a/include/linux/io_uring.h +++ b/include/linux/io_uring.h @@ -27,7 +27,7 @@ struct io_uring_cmd { const void *cmd; union { /* callback to defer completions to task context */ - void (*task_work_cb)(struct io_uring_cmd *cmd); + void (*task_work_cb)(struct io_uring_cmd *cmd, unsigned); /* used for polled completion */ void *cookie; }; @@ -39,9 +39,10 @@ struct io_uring_cmd { #if defined(CONFIG_IO_URING) int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, struct iov_iter *iter, void *ioucmd); -void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2); +void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2, + unsigned issue_flags); void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, - void (*task_work_cb)(struct io_uring_cmd *)); + void (*task_work_cb)(struct io_uring_cmd *, unsigned)); struct sock *io_uring_get_socket(struct file *file); void __io_uring_cancel(bool cancel_all); void __io_uring_free(struct task_struct *tsk); @@ -72,11 +73,11 @@ static inline int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, return -EOPNOTSUPP; } static inline void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, - ssize_t ret2) + ssize_t ret2, bool *locked) { } static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, - void (*task_work_cb)(struct io_uring_cmd *)) + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) { } static inline struct sock *io_uring_get_socket(struct file *file) diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c index 2e4c483075d3..9a1dee571872 100644 --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -15,12 +15,13 @@ static void io_uring_cmd_work(struct io_kiocb *req, bool *locked) { struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); + unsigned issue_flags = *locked ? 0 : IO_URING_F_UNLOCKED; - ioucmd->task_work_cb(ioucmd); + ioucmd->task_work_cb(ioucmd, issue_flags); } void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, - void (*task_work_cb)(struct io_uring_cmd *)) + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) { struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); @@ -42,7 +43,8 @@ static inline void io_req_set_cqe32_extra(struct io_kiocb *req, * Called by consumers of io_uring_cmd, if they originally returned * -EIOCBQUEUED upon receiving the command. */ -void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2) +void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2, + unsigned issue_flags) { struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); @@ -56,7 +58,7 @@ void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2) /* order with io_iopoll_req_issued() checking ->iopoll_complete */ smp_store_release(&req->iopoll_completed, 1); else - io_req_complete_post(req, 0); + io_req_complete_post(req, issue_flags); } EXPORT_SYMBOL_GPL(io_uring_cmd_done); -- Jens Axboe