> Il giorno 12 giu 2019, alle ore 15:39, Tejun Heo <tj@xxxxxxxxxx> ha scritto: > > On Wed, Jun 12, 2019 at 09:32:07AM +0200, Paolo Valente wrote: >> Could you elaborate a little more on this? > > Doesn't seem like you did. > >> bfq code for setting up and handling io.weight (more precisely >> io.bfq.weight) is a copy and paste of cfq code. > > Please take a look at the documentations under > Documentation/cgroup-v1/blk-iocontroller.txt and > Documentation/admin-guide/cgroup-v2.rst. > I'm sorry, but I don't see what doesn't match between BFQ's and CFQ's implementations of the weight parameter. So, if you agree, let me paste the two snippets for v1 that involve weights. So maybe you can at least tell me 'here' (then I'll try the same with v2). ---------------------------------------------------------------------- mount -t tmpfs cgroup_root /sys/fs/cgroup mkdir /sys/fs/cgroup/blkio mount -t cgroup -o blkio none /sys/fs/cgroup/blkio - Create two cgroups mkdir -p /sys/fs/cgroup/blkio/test1/ /sys/fs/cgroup/blkio/test2 - Set weights of group test1 and test2 echo 1000 > /sys/fs/cgroup/blkio/test1/blkio.weight echo 500 > /sys/fs/cgroup/blkio/test2/blkio.weight -> This is exactly how you set weights with BFQ ---------------------------------------------------------------------- Details of cgroup files ======================= Proportional weight policy files -------------------------------- - blkio.weight - Specifies per cgroup weight. This is default weight of the group on all the devices until and unless overridden by per device rule. (See blkio.weight_device). Currently allowed range of weights is from 10 to 1000. -> This is the exact implementation of the weight parameter in BFQ BFQ does not implement weight_device, but we are not talking about weight_device here. More precisely, *nothing* implements weight_device any longer in cgroups-v1, so the documentation is wrong altogether. Looking forward to your feedback, Paolo > Thanks. > > -- > tejun
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