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Fri, 17 Jan 2020 15:15:35 -0800 (PST) Received: from [192.168.43.134] ([109.126.145.157]) by smtp.gmail.com with ESMTPSA id k7sm3169478wmi.19.2020.01.17.15.15.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Jan 2020 15:15:35 -0800 (PST) To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <37a04c11e980f49cb17a4fd071d2d71a291a8fd5.1579299684.git.asml.silence@gmail.com> From: Pavel Begunkov 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 0/2] optimise sqe-to-req flags Message-ID: Date: Sat, 18 Jan 2020 02:14:56 +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="HtH6ZyO0HhlkxDivhICsp4B8tL01mmhAq" 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) --HtH6ZyO0HhlkxDivhICsp4B8tL01mmhAq Content-Type: multipart/mixed; boundary="2soa8hgoM5OZvAd8Mrev0PPxljXQz00xS"; protected-headers="v1" From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: Subject: Re: [PATCH 0/2] optimise sqe-to-req flags References: <37a04c11e980f49cb17a4fd071d2d71a291a8fd5.1579299684.git.asml.silence@gmail.com> In-Reply-To: --2soa8hgoM5OZvAd8Mrev0PPxljXQz00xS Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 18/01/2020 01:49, Jens Axboe wrote: > On 1/17/20 3:41 PM, Pavel Begunkov wrote: >> *lost the cover-letter, but here we go* >> >> The main idea is to optimise code like the following by directly >> copying sqe flags: >> >> if (sqe_flags & IOSQE_IO_HARDLINK) >> req->flags |=3D REQ_F_HARDLINK; >> >> The first patch is a minor cleanup, and the second one do the >> trick. No functional changes. >> >> The other thing to consider is whether to use such flags as=20 >> REQ_F_LINK =3D IOSQE_IO_LINK, or directly use IOSQE_IO_LINK instead. >=20 > I think we should keep the names separate. I think it looks fine, thoug= h > I do wish that we could just have both in an enum and not have to do > weird naming. We sometimes do: >=20 > enum { > __REQ_F_FOO > }; >=20 > #define REQ_F_FOO (1U << __REQ_F_FOO) > I thought it will be too bulky as it needs retyping the same name many ti= mes. Though, it solves numbering problem and is less error-prone indeed. Let m= e to play with it a bit. BTW, there is another issue from development perspective -- it's harder t= o find from where a flag is came. E.g. search for REQ_F_FOO won't give you a pla= ce, where it was set. SQE_INHERITED_FLAGS is close in the code to its usage e= xactly for this reason. > and with that we could have things Just Work in terms of numbering, if > we keep the overlapped values at the start. Would need IOSQE_* to also > use an enum, ala: >=20 > enum { > __IOSQE_FIXED_FILE, > __IOSQE_IO_DRAIN, > ... > }; >=20 I tried to not modify the userspace header. Wouldn't it be better to add = _BIT postfix instead of the underscores? > and then do >=20 > #define IOSQE_FIXED_FILE (1U << __IOSQE_FIXED_FILE) >=20 > and have the __REQ enum start with >=20 > enum { > __REQ_F_FIXED_FILE =3D __IOSQE_FIXED_FILE, > __REQ_F_IO_DRAIN =3D __IOSQE_IO_DRAIN, > ... > __REQ_F_LINK_NEXT, > __REQ_F_FAIL_LINK, > ... > }; >=20 --=20 Pavel Begunkov --2soa8hgoM5OZvAd8Mrev0PPxljXQz00xS-- --HtH6ZyO0HhlkxDivhICsp4B8tL01mmhAq Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+6JuPTjTbx479o3OWt5b1Glr+6UFAl4iP/AACgkQWt5b1Glr +6WTeRAAkmrvDTMrEDVgE43duThVOdO7S4rz1dqBkv4QRjutTrDzt1UxXuhwFnW5 1W337bdXXQiJbXZEabY/DfwJLWFbGPK1KPblPOhzKK2jVgY+Nlu8cIHvVwu70Z3H 57pNclXOuScaoyDmrD0D/UIVpEJmL+E7XKbce/9QEVajkncbbFcyXhYG6MV2CTGl ppQ/4z5rYfYuCK9kffgNHbU+Z7IqTtRavvq2a+eo3qohUkeUBM+aEOgmBjkbx1Ji osZtXhUpPPVbxl0cSnDRyp5oSKwCQyzKOyjXI2K/MYewxtFFKfPcIf7CfFeQLRyR dcmT4OyXaud7J/zWPVYVYqNYh7Bw8KXWlunsvvQWAEDtlCcpyTaHM6rp34yYpLD8 v00AmI1Fz+prT+xZyyXu9piX3nHrDwNmtjeLN4yLOxi+3QrOl6Pi77GFFPxtUi1S bHGvJ6bHLgMcZyvq161jmYuDreDOgwzIGibck3HUl7DS1R4l5d6ncpj07cc9LyYT YgAYwTC3bF48qi+QiX9mnwGc7q1SXDv57lcaXusBJuugBCHqKO+3S4SDlhjFpckt w+OD/Hd1M3gHWp26ZmsQXnHAdMjbPR5KfjoCIwuPbHIHhxqmKXppd5DPIP1UqCbg aI36zbXg5MSbiESltnEZC4Wo3Cd/j6BgO2ez8yy3wE8OTaVgHlU= =949l -----END PGP SIGNATURE----- --HtH6ZyO0HhlkxDivhICsp4B8tL01mmhAq--