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Mon, 16 Dec 2019 15:38:31 -0800 (PST) From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Subject: Re: [PATCH 3/3] io_uring: move *queue_link_head() from common path Message-ID: <17f7900c-385f-0dfa-11bf-af99d080f894@gmail.com> Date: Tue, 17 Dec 2019 02:38:09 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="C7S0tkHwjcStuGlt7fvdT11hp6MQXVShU" Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --C7S0tkHwjcStuGlt7fvdT11hp6MQXVShU Content-Type: multipart/mixed; boundary="yFO8RYBx2MIVzHGVJe03in1ZOfmp8Aca2"; protected-headers="v1" From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <17f7900c-385f-0dfa-11bf-af99d080f894@gmail.com> Subject: Re: [PATCH 3/3] io_uring: move *queue_link_head() from common path References: In-Reply-To: --yFO8RYBx2MIVzHGVJe03in1ZOfmp8Aca2 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 17/12/2019 02:22, Pavel Begunkov wrote: > Move io_queue_link_head() to links handling code in io_submit_sqe(), > so it wouldn't need extra checks and would have better data locality. >=20 > Signed-off-by: Pavel Begunkov > --- > fs/io_uring.c | 32 ++++++++++++++------------------ > 1 file changed, 14 insertions(+), 18 deletions(-) >=20 > diff --git a/fs/io_uring.c b/fs/io_uring.c > index bac9e711e38d..a880ed1409cb 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -3373,13 +3373,15 @@ static bool io_submit_sqe(struct io_kiocb *req,= struct io_submit_state *state, > struct io_kiocb **link) > { > struct io_ring_ctx *ctx =3D req->ctx; > + unsigned int sqe_flags; > int ret; > =20 > + sqe_flags =3D READ_ONCE(req->sqe->flags); > req->user_data =3D READ_ONCE(req->sqe->user_data); > trace_io_uring_submit_sqe(ctx, req->user_data, true, req->in_async); > =20 > /* enforce forwards compatibility on users */ > - if (unlikely(req->sqe->flags & ~SQE_VALID_FLAGS)) { > + if (unlikely(sqe_flags & ~SQE_VALID_FLAGS)) { > ret =3D -EINVAL; > goto err_req; > } > @@ -3402,10 +3404,10 @@ static bool io_submit_sqe(struct io_kiocb *req,= struct io_submit_state *state, > if (*link) { > struct io_kiocb *head =3D *link; > =20 > - if (req->sqe->flags & IOSQE_IO_DRAIN) > + if (sqe_flags & IOSQE_IO_DRAIN) > head->flags |=3D REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN; > =20 > - if (req->sqe->flags & IOSQE_IO_HARDLINK) > + if (sqe_flags & IOSQE_IO_HARDLINK) > req->flags |=3D REQ_F_HARDLINK; > =20 > if (io_alloc_async_ctx(req)) { > @@ -3421,9 +3423,15 @@ static bool io_submit_sqe(struct io_kiocb *req, = struct io_submit_state *state, > } > trace_io_uring_link(ctx, req, head); > list_add_tail(&req->link_list, &head->link_list); > - } else if (req->sqe->flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) { > + > + /* last request of a link, enqueue the link */ > + if (!(sqe_flags & IOSQE_IO_LINK)) { This looks suspicious (as well as in the current revision). Returning bac= k to my questions a few days ago can sqe->flags have IOSQE_IO_HARDLINK, but= not IOSQE_IO_LINK? I don't find any check. In other words, should it be as follows? !(sqe_flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) > + io_queue_link_head(head); > + *link =3D NULL; > + } > + } else if (sqe_flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) { > req->flags |=3D REQ_F_LINK; > - if (req->sqe->flags & IOSQE_IO_HARDLINK) > + if (sqe_flags & IOSQE_IO_HARDLINK) > req->flags |=3D REQ_F_HARDLINK; > =20 > INIT_LIST_HEAD(&req->link_list); > @@ -3540,10 +3548,8 @@ static int io_submit_sqes(struct io_ring_ctx *ct= x, unsigned int nr, > } > =20 > for (i =3D 0; i < nr; i++) { > - struct io_kiocb *req; > - unsigned int sqe_flags; > + struct io_kiocb *req =3D io_get_req(ctx, statep); > =20 > - req =3D io_get_req(ctx, statep); > if (unlikely(!req)) { > if (!submitted) > submitted =3D -EAGAIN; > @@ -3563,8 +3569,6 @@ static int io_submit_sqes(struct io_ring_ctx *ctx= , unsigned int nr, > } > =20 > submitted++; > - sqe_flags =3D req->sqe->flags; > - > req->ring_file =3D ring_file; > req->ring_fd =3D ring_fd; > req->has_user =3D *mm !=3D NULL; > @@ -3572,14 +3576,6 @@ static int io_submit_sqes(struct io_ring_ctx *ct= x, unsigned int nr, > req->needs_fixed_file =3D async; > if (!io_submit_sqe(req, statep, &link)) > break; > - /* > - * If previous wasn't linked and we have a linked command, > - * that's the end of the chain. Submit the previous link. > - */ > - if (!(sqe_flags & IOSQE_IO_LINK) && link) { > - io_queue_link_head(link); > - link =3D NULL; > - } > } > =20 > if (link) >=20 --=20 Pavel Begunkov --yFO8RYBx2MIVzHGVJe03in1ZOfmp8Aca2-- --C7S0tkHwjcStuGlt7fvdT11hp6MQXVShU Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+6JuPTjTbx479o3OWt5b1Glr+6UFAl34FWIACgkQWt5b1Glr +6VTMg//UX504vCQR4vLbo8GO0tzZBv3qvSQ3FxdL8fpHa8WLSZkRAXp9M2DRaF6 T93044csOQ+qq/kKkXVpScwlYpu7wtZaTtyy9xUwmkEMjl8kiWezBu+EfuKg+Pp/ yCv5yYjAVLxy5htNTSiR+3vQnN7GO30zmv0u4ykJ8kAKEkkS+9i16aFTsWUcODq6 wl3E2dLhqT260kRa5iNmAkJl0U5BHHuSj7NhzspPrNlxTOtCLfzdGr4ssW7kOFRs bYZf3TtAeNywbUPGXrd6pwro4teHCsFazkXGqdg/Af2GjJmLQreeE0Sujr517HW5 VeO7K51vTRSh1JwbcPQDJhfv6WirbR9waLjGElOsVPPfjNslCKB3OWQTXwft2zFY 781xl8rJmJMQj93vmcFGpWwTe3ftjewFwjeADhl2jxAAcIJR6660GrtSMEvsuvAX eXg3O1PumeDv8DpPbnCX7eyx/bN00caFkX05a9Opwi8Lx/AolsqtEtvDMozH7hxb ReMRxf3BF5mZi1biwyXRLp3IZ+HHHRTiKXIWejKeHv9AB3NUfFzjLL2VEKPeVILA y/Jso5IfQbQYvq5JEtJDFNzpwZu/9C0ci21QWZqBGVLsKgyLHPzWCtVqOqebT4gX 7nKHRwo0RMSgXoOQ3EDFTGAOqWYmfrVI0lbmrOtMDOACU0c3Wzo= =efnH -----END PGP SIGNATURE----- --C7S0tkHwjcStuGlt7fvdT11hp6MQXVShU--