Messages in this thread | | | Date | Tue, 18 Mar 2008 18:22:51 +0900 (JST) | Subject | [PATCH O/4] Block I/O tracking | From | Hirokazu Takahashi <> |
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Hi,
When you want to implement some kind of Block I/O controllers, you have to determine who issued each I/O. I just implemented this feature, with which you can track down the I/Os.
When you have to find the owner which issued the I/O, it is the one which owns the page where the IO is going to start. The cgroup memory subsystem already has this feature, so I realized that it would make easy to implemented Block I/O tracking mechanism on the memory subsystem. I named it "bio cgroup."
I made dm-ioband -- I/O bandwidth controller -- work with the bio cgroup, whose implementation is just experimental though.
I have a plan on making the bio cgroup support io_context. Each bio cgroup will have one or more io_contexts so the I/O bandwidth controller can use it to control the bandwidths. I also have another plan on move the implementation of dm-ioband from the device mapper layer to somewhere before the I/O schedulers in the block layer.
The following patches are against linux-2.6.25-rc5-mm1 and you have to apply the patch of dm-ioband v0.0.3, which you can download from http://people.valinux.co.jp/~ryov/dm-ioband/patches/dm-ioband-0.0.3.patch before applying the following patches.
Let's say you want make two bio cgroups and assign them to ioband device "ioband1". First, you have to mount the bio cgroup filesystem.
# mount -t cgroup -o bio none /cgroup/bio
Then, you make new bio cgroups and put some processes in them.
# mkdir /cgroup/bio/bgroup1 # mkdir /cgroup/bio/bgroup2 # echo 1234 /cgroup/bio/bgroup1/tasks # echo 5678 /cgroup/bio/bgroup1/tasks
Now you check the ids of the bio cgroups which you just created.
# cat /cgroup/bio/bgroup1/bio.id 1 # cat /cgroup/bio/bgroup2/bio.id 2
Finally, you can attach the cgroups to "ioband1" and assign them weights.
# dmsetup message ioband1 0 type cgroup # dmsetup message ioband1 0 attach 1 # dmsetup message ioband1 0 attach 2 # dmsetup message ioband1 0 weight 1:30 # dmsetup message ioband1 0 weight 2:60
You can find the manual of dm-ioband at http://people.valinux.co.jp/~ryov/dm-ioband/manual/index.html. But the user interface for the bio cgroup is temporal and it will be changed after the io_context support.
Thank you, Hirokazu Takahashi.
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