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[88.147.74.24]) by smtp.gmail.com with ESMTPSA id m8sm1819441wrn.12.2019.05.30.08.02.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 May 2019 08:02:27 -0700 (PDT) From: Paolo Valente Message-Id: <406CC451-A318-4EC5-942D-4CCFABFBC402@linaro.org> Content-Type: multipart/signed; boundary="Apple-Mail=_0A0ED018-47B3-4501-BF94-C2C77CE3E17E"; protocol="application/pgp-signature"; micalg=pgp-sha256 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.8\)) Subject: Re: [PATCH 0/2] block, bfq: add weight symlink to the bfq.weight cgroup parameter Date: Thu, 30 May 2019 17:02:25 +0200 In-Reply-To: <20190521080155.36178-1-paolo.valente@linaro.org> Cc: linux-block , kernel list , Ulf Hansson , Linus Walleij , Mark Brown , noreply-spamdigest via bfq-iosched , Oleksandr Natalenko , Angelo Ruocco To: Jens Axboe References: <20190521080155.36178-1-paolo.valente@linaro.org> X-Mailer: Apple Mail (2.3445.104.8) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org --Apple-Mail=_0A0ED018-47B3-4501-BF94-C2C77CE3E17E Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Hi Jens, have you had time to look into this? Thanks, Paolo > Il giorno 21 mag 2019, alle ore 10:01, Paolo Valente = ha scritto: >=20 > Many userspace tools and services use the proportional-share policy of > the blkio/io cgroups controller. The CFQ I/O scheduler implemented > this policy for the legacy block layer. To modify the weight of a > group in case CFQ was in charge, the 'weight' parameter of the group > must be modified. On the other hand, the BFQ I/O scheduler implements > the same policy in blk-mq, but, with BFQ, the parameter to modify has > a different name: bfq.weight (forced choice until legacy block was > present, because two different policies cannot share a common = parameter > in cgroups). >=20 > Due to CFQ legacy, most if not all userspace configurations still use > the parameter 'weight', and for the moment do not seem likely to be > changed. But, when CFQ went away with legacy block, such a parameter > ceased to exist. >=20 > So, a simple workaround has been proposed by Johannes [1] to make all > configurations work: add a symlink, named weight, to bfq.weight. This > pair of patches adds: > 1) the possibility to create a symlink to a cgroup file; > 2) the above 'weight' symlink. >=20 > Thanks, > Paolo >=20 > [1] https://lkml.org/lkml/2019/4/8/555 >=20 > Angelo Ruocco (2): > cgroup: let a symlink too be created with a cftype file > block, bfq: add weight symlink to the bfq.weight cgroup parameter >=20 > block/bfq-cgroup.c | 6 ++++-- > include/linux/cgroup-defs.h | 3 +++ > kernel/cgroup/cgroup.c | 33 +++++++++++++++++++++++++++++---- > 3 files changed, 36 insertions(+), 6 deletions(-) >=20 > -- > 2.20.1 --Apple-Mail=_0A0ED018-47B3-4501-BF94-C2C77CE3E17E Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEpYoduex+OneZyvO8OAkCLQGo9oMFAlzv8IEACgkQOAkCLQGo 9oPbeg//bjA9YtGMRt5whQ3aCQke6yuOS6cLXKdGEGOy6Mw2OC03I4wRDUjRZA+L DGHOipvDtans0+xVYd+m8UCeq3ZklbaZA7qeasP2rwv3sb0pC60p1luy24nWjkoP OlfesidSq98l7zQL30ZjfOvP0X0DskTVkNSPih7U0TbkwQ6jl6/o+inbGjNKzP4p 4cQuLfHPG4ipL0ds/BiNRd+ihIzuIrtftwAwEaklhA7XOfnmZtGkA5hrIN+U4NNx xHceCTjv7+X2+Uk0aFGTE4ch5fVHQvAbM7b1wr/ERgZd/ProT07gqG0PzwGfPI9q MC4MhXsWgmymuMcn+6CFCRgSBJWxNSa+2uf66T8j26osYMgQ6RBZkgp2NLKIFhvX eKBtS/p6NtLYTTYOHUlLzeHf6tIbkKf6DvaTQZ4WfmDFbaRBFsqobfjmyJtr9GZp erIwdWEhqlSBgv0pseSDF0nePD5egshMmM3Vhfbbgisq99yUQBUKEcWM52A5E+Eg qZfn5lbrxY6GlnhMSzEbZg5Dkwyb2WnIAXh94Br35FA49D/FlJIZbzppbOOBzSEP gQ65irL0W2X3rRvIYWYCcGAbvH+NEjFE1LQY0zwansnOxv2UbZgg23RY+quEWuny XigI9gpCnhe9aLkjggRRRiAKf6lNHrGXIbwA2ACAZ6WtYX/B3uA= =tEiY -----END PGP SIGNATURE----- --Apple-Mail=_0A0ED018-47B3-4501-BF94-C2C77CE3E17E--