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Thu, 25 May 2023 17:53:41 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPA id 20230525082004epcas5p1d05da68508feff3f9dd82646a0b40aff~iVR_cNBga1722317223epcas5p1Z; Thu, 25 May 2023 08:20:04 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20230525082004epsmtrp20a42dc5a7d130185a806134c361fc753~iVR_bk-ee0256602566epsmtrp2k; Thu, 25 May 2023 08:20:04 +0000 (GMT) X-AuditID: b6c32a4a-c47ff7000001af51-62-646f2215aebf Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 31.90.27706.43A1F646; Thu, 25 May 2023 17:20:04 +0900 (KST) Received: from localhost.localdomain (unknown [109.105.118.125]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20230525082003epsmtip1a3d73cb074325a19dd202ef614a92cd3~iVR9iFYoL1097610976epsmtip1O; Thu, 25 May 2023 08:20:03 +0000 (GMT) From: Wenwen Chen To: axboe@kernel.dk, asml.silence@gmail.com Cc: io-uring@vger.kernel.org, Wenwen Chen , Kanchan Joshi Subject: [PATCH v2] io_uring: unlock sqd->lock before sq thread release CPU Date: Thu, 25 May 2023 16:26:26 +0800 Message-Id: <20230525082626.577862-1-wenwen.chen@samsung.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrPKsWRmVeSWpSXmKPExsWy7bCmuq6oUn6KwbUmK4s5q7YxWqy+289m 8a71HIvF0f9v2Sx+dd9ltDg74QOrxdQtO5gc2D12zrrL7nH5bKlH35ZVjB6fN8kFsERl22Sk JqakFimk5iXnp2TmpdsqeQfHO8ebmhkY6hpaWpgrKeQl5qbaKrn4BOi6ZeYAHaCkUJaYUwoU CkgsLlbSt7Mpyi8tSVXIyC8usVVKLUjJKTAp0CtOzC0uzUvXy0stsTI0MDAyBSpMyM74vGYb a8FO7ooPD5YyNzCu4uxi5OSQEDCRaJo1h7GLkYtDSGA3o0TL8UYo5xOjxKmtm5khnG+MEp8u NTDDtNzZt5YNIrEXqKqpB8r5yijRt2EzG0gVm4C2xPu1LYwgtgiQ/frxVBYQm1kgS+LS22/s ILawgLfEhT2fweIsAqoS65c8BIvzCthK3Di8kw1im7zExNl3GSHighInZz6BmiMv0bx1Nth5 EgLH2CVOft4DdZ6LxISzx9ghbGGJV8e3QNlSEp/f7YUaWiwx8eAXdojmBkaJ4xe/skAkrCX+ XdkDZHMAbdCUWL9LHyIsKzH11DomiMV8Er2/nzBBxHkldsyDsVUlzj4/xwphS0u0zGmAintI NPztB7tBSCBWoqNhHcsERvlZSP6ZheSfWQibFzAyr2KUTC0ozk1PLTYtMMpLLYdHbXJ+7iZG cErU8trB+PDBB71DjEwcjIcYJTiYlUR4T5RnpwjxpiRWVqUW5ccXleakFh9iNAUG8kRmKdHk fGBSziuJNzSxNDAxMzMzsTQ2M1QS51W3PZksJJCeWJKanZpakFoE08fEwSnVwLSk/QWLY/pv jqNHC3ds8cgo9zgptfL0V97JmU/7egX9DVkcLk1fa+VQ6PUzcrrukRU2rNU1CretVz8wOhp6 evFyOZ+0Xc0x5mtUFP9/nhP3TqzSvNF1qbuufqth47fr+9XVMsReptXGa2jclE0+uaAsua3o zlG9eX3/1pZszeS6qM2W8igoatWlv4sqSuMOsn27PK/1xk+l0+89vU9IWX6379Kf9MMiQpuH XSLgZ73WX363Npu58+d9lZ8n7+7ruFFMYKmzwpRfJ9q2z9+UW7vH83lyFfedO+qrqqO9M9r9 fKc3Ll0e715WcDP1yaT5B1lntmw59vNdwySZpU88HrTf2vWwy/bcCkHRhUtCViuxFGckGmox FxUnAgCbTUXREgQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrBLMWRmVeSWpSXmKPExsWy7bCSnK6JVH6KwY/ZOhZzVm1jtFh9t5/N 4l3rORaLo//fsln86r7LaHF2wgdWi6lbdjA5sHvsnHWX3ePy2VKPvi2rGD0+b5ILYInisklJ zcksSy3St0vgyvi8ZhtrwU7uig8PljI3MK7i7GLk5JAQMJG4s28tWxcjF4eQwG5GiQuHlzNC JKQlDl37zAphC0us/PecHaLoM6PE+x13WEASbALaEu/XtgA1cHCICOhKNN5VAAkzC+RI3Lz2 HqxEWMBb4sKez2A2i4CqxPolD9lBbF4BW4kbh3eyQcyXl5g4+y4jRFxQ4uTMJywQc+QlmrfO Zp7AyDcLSWoWktQCRqZVjJKpBcW56bnFhgWGeanlesWJucWleel6yfm5mxjBgamluYNx+6oP eocYmTgYDzFKcDArifCeKM9OEeJNSaysSi3Kjy8qzUktPsQozcGiJM57oetkvJBAemJJanZq akFqEUyWiYNTqoHptHvSekH1NXE88lefRDC8yJ6U53vrrae1q9XWpfsyz+fsu+918I/lOoP3 Bu8Ov/tw9ctRBa8p5nmfAj4u/asnJud+75kuz5nVLLveH+gJ+PWlvaz+pneYytfeVewuJ3iX n+RfxF3u/1/mpU/8gv83d/2a2GQh7NTEyJO9r0vprZbTmRs/Qm4q3VuY2f9s5QJfu5kr9kSr fnin+YZn7ZqFzay75KZ/CnjP+UFj72EmtVbOgPQHEfNYTs7UmvwyTXj+ArGZPc2vZb5kfZlx g/tNu3nCZU1L4x/PpzOE8M9/cnRnikXIjO+bul9wbeO/oNE28WTRkwimUz9q9cVcFv6zLp+h HH5mYXDKTPdtVfaVkkosxRmJhlrMRcWJADsCy6S7AgAA X-CMS-MailID: 20230525082004epcas5p1d05da68508feff3f9dd82646a0b40aff X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230525082004epcas5p1d05da68508feff3f9dd82646a0b40aff References: Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org The sq thread actively releases CPU resources by calling the cond_resched() and schedule() interfaces when it is idle. Therefore, more resources are available for other threads to run. There exists a problem in sq thread: it does not unlock sqd->lock before releasing CPU resources every time. This makes other threads pending on sqd->lock for a long time. For example, the following interfaces all require sqd->lock: io_sq_offload_create(), io_register_iowq_max_workers() and io_ring_exit_work(). Before the sq thread releases CPU resources, unlocking sqd->lock will provide the user a better experience because it can respond quickly to user requests. Signed-off-by: Kanchan Joshi Signed-off-by: Wenwen Chen --- V1 -> V2: Make sqd lock shuffle dependent on the need to reschedule io_uring/sqpoll.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 9db4bc1f521a..5e329e3cd470 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -255,9 +255,13 @@ static int io_sq_thread(void *data) sqt_spin = true; if (sqt_spin || !time_after(jiffies, timeout)) { - cond_resched(); if (sqt_spin) timeout = jiffies + sqd->sq_thread_idle; + if (unlikely(need_resched())) { + mutex_unlock(&sqd->lock); + cond_resched(); + mutex_lock(&sqd->lock); + } continue; } -- 2.27.0