Il giorno 12 dic 2018, alle ore 20:30, Chris Murphy
<lists(a)colorremedies.com> ha scritto:
Really Readding devel@ this time...
On Wed, Dec 12, 2018 at 11:08 AM stan <stanl-fedorauser(a)vfemail.net> wrote:
> On Tue, 11 Dec 2018 11:48:29 -0000
> "Alan Jenkins" <alan.christopher.jenkins(a)gmail.com> wrote:
>>  BFQ:
>>  "I'd prefer if the distros would lead the way on this, as theyare
>> the ones that will most likely see the most bug reports" - Jens
>> Axboe, https://www.spinics.net/lists/linux-block/msg31062.html
> I compiled a custom kernel from the fedora src.rpm for 4.19.8. I turned
> off all schedulers except NOOP and BFQ. But there was no way in the
> configuration process (make menuconfig) to set BFQ as default. I tried
> setting it in kernel-local, but the build process errored because it
> said NOOP is the default and that disagreed with my choice. I'm
> running the kernel and it is using noop. And there is no way to change
> it in the /sys hierarchy.
> So, how do I get a fedora kernel to run BFQ?
Yep, so far in 4.20 there is neither a CONFIG_DEFAULT_BFQ or
CONFIG_DEFAULT_IOSCHED="bfq" near as I can tell. Maybe it's different
Yep, hundreds of kilobytes of email have been spent trying to convince
Jens Axboe that a default option had to be kept for blk-mq too. At no
avail. If anyone wants to restart this fight, I'll be on your side.
I used two boot params: scsi_mod.use_blk_mq=1
Yes, this is needed to switch to blk-mq, until 4.21, when there will
be no legacy block any longer. One can also set the corresponding
option in the kernel configuration.
I'm not sure this option works with blkmq. IIRC doing this may even
cause system failures with blk-mq (but maybe this has been fixed).
AFAIK, the only way is to set bfq manually or through, e.g., dev
rules, but YMMV.
think that's a good way for a distribution to set the default though.
I set the following in /etc/default/grub and then ran grub2-mkconfig
(not on Rawhide!)
GRUB_CMDLINE_LINUX="scsi_mod.use_blk_mq=1 elevator=bfq zswap.enabled=1
I also created /etc/dracut.conf.d/bfq.conf containing:
add_drivers+=" bfq "
yes, with spaces, and rebuilt the initramfs
But upon reboot, total implosion. Piles of USB errors and disconnects
(the boot device is a Samsung FIT USB stick which fits flush in an
Intel NUC). I didn't have time to troubleshoot what's causing this
problem, other than to plug the USB stick into another computer to
verify the stick is good and hasn't been corrupted. It's possibly
related the mq-blk bug in 4.19.0 through 4.19.7 - so I've since
upgraded to 4.19.8 which as those patches, but I haven't had a chance
I doubt this is bfq fault, as bfq is rather frequently used for USB
too. Probably bfq has not been activated at all.
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