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* [PATCH 0/1] bfq: remove prefixes from cgroup filenames
@ 2019-04-08 14:39 Paolo Valente
  2019-04-08 14:39 ` [PATCH 1/1] block, bfq: delete "bfq" prefix " Paolo Valente
  0 siblings, 1 reply; 18+ messages in thread
From: Paolo Valente @ 2019-04-08 14:39 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, linux-kernel, ulf.hansson, linus.walleij, broonie,
	bfq-iosched, oleksandr, Paolo Valente

When bfq was merged into mainline, there were two I/O schedulers that
implemented the proportional-share policy: bfq for blk-mq and cfq for
legacy blk. bfq's interface files in the blkio/io controller have the
same names as cfq. But the cgroups interface doesn't allow two
entities to use the same name for their files, so for bfq we had to
prepend the "bfq" prefix to each of its files. However no legacy code
uses these modified file names. This naming also causes confusion, as,
e.g., in [1].

So we tried to propose a solution to enable entities to share
interface files for identical parameters [2]. But our solution didn't
convince Tejun, and we got stuck.

Fortunately, now cfq has gone with legacy blk, so there is no need any
longer for prefixes in (the never used) bfq names. In view of this
fact, here's an alternative patch, which simply removes these
prefixes, thereby enabling legacy code to truly use the proportional
share policy in blk-mq. This postpones the problem of sharing common
interface files, to when, e.g., some new proportional-share policy
gets proposed.

Paolo

[1] https://github.com/systemd/systemd/issues/7057
[2] https://lwn.net/ml/linux-block/20181119103424.3853-1-paolo.valente@linaro.org/

Angelo Ruocco (1):
  block, bfq: delete "bfq" prefix from cgroup filenames

 block/bfq-cgroup.c | 46 +++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

--
2.20.1

^ permalink raw reply	[flat|nested] 18+ messages in thread
* [PATCH 0/1] block, bfq: remove bfq prefix from cgroups filenames
@ 2019-09-09  7:31 Paolo Valente
  2019-09-09  7:31 ` [PATCH 1/1] block, bfq: delete "bfq" prefix from cgroup filenames Paolo Valente
  0 siblings, 1 reply; 18+ messages in thread
From: Paolo Valente @ 2019-09-09  7:31 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, linux-kernel, ulf.hansson, linus.walleij,
	bfq-iosched, oleksandr, Tejun Heo, cgroups, Paolo Valente

Hi Jens,
now that BFQ's weight interface has been fixed [1], can we proceed
with this change?

In addition to acking this solution, in [2] Tejun already suggested a
reduced version of the present patch. In Tejun's version, only
bfq.weight is changed. But I guess that legacy code may use also some
of the other bfq parameters in cgroups, without the bfq prefix. Apart
from that, any version is ok for me, provided that it solves the
current confusing situation for userspace [3].

Thanks,
Paolo

[1] https://lkml.org/lkml/2019/8/27/1716
[2] https://www.mail-archive.com/linux-block@vger.kernel.org/msg35823.html
[3] https://github.com/systemd/systemd/issues/7057

Angelo Ruocco (1):
  block, bfq: delete "bfq" prefix from cgroup filenames

 block/bfq-cgroup.c | 46 +++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

--
2.20.1

^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2019-09-09  7:32 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-08 14:39 [PATCH 0/1] bfq: remove prefixes from cgroup filenames Paolo Valente
2019-04-08 14:39 ` [PATCH 1/1] block, bfq: delete "bfq" prefix " Paolo Valente
2019-04-08 14:49   ` Johannes Thumshirn
2019-04-08 14:54     ` Paolo Valente
2019-04-08 15:01       ` Jens Axboe
2019-04-08 15:04       ` Johannes Thumshirn
2019-04-08 15:05         ` Jens Axboe
2019-04-08 15:06           ` Paolo Valente
2019-04-08 15:11             ` Jens Axboe
2019-04-08 15:15               ` Paolo Valente
2019-04-08 15:08           ` Johannes Thumshirn
2019-04-08 15:13             ` Jens Axboe
2019-04-08 15:19               ` Paolo Valente
2019-04-08 15:14             ` Paolo Valente
2019-04-08 15:17               ` Jens Axboe
2019-04-08 17:01                 ` Paolo Valente
2019-04-10 11:42           ` Ulf Hansson
2019-09-09  7:31 [PATCH 0/1] block, bfq: remove bfq prefix from cgroups filenames Paolo Valente
2019-09-09  7:31 ` [PATCH 1/1] block, bfq: delete "bfq" prefix from cgroup filenames Paolo Valente

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