Messages in this thread | | | Date | Tue, 27 Jul 2010 15:39:51 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC][PATCH 00/11] blkiocg async support |
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On Mon, 26 Jul 2010 23:40:07 -0700 Greg Thelen <gthelen@google.com> wrote:
> On Sun, Jul 25, 2010 at 11:41 PM, Balbir Singh > <balbir@linux.vnet.ibm.com> wrote: > > * Munihiro Ikeda <m-ikeda@ds.jp.nec.com> [2010-07-08 22:57:13]: > > > >> These RFC patches are trial to add async (cached) write support on blkio > >> controller. > >> > >> Only test which has been done is to compile, boot, and that write bandwidth > >> seems prioritized when pages which were dirtied by two different processes in > >> different cgroups are written back to a device simultaneously. I know this > >> is the minimum (or less) test but I posted this as RFC because I would like > >> to hear your opinions about the design direction in the early stage. > >> > >> Patches are for 2.6.35-rc4. > >> > >> This patch series consists of two chunks. > >> > >> (1) iotrack (patch 01/11 -- 06/11) > >> > >> This is a functionality to track who dirtied a page, in exact which cgroup a > >> process which dirtied a page belongs to. Blkio controller will read the info > >> later and prioritize when the page is actually written to a block device. > >> This work is originated from Ryo Tsuruta and Hirokazu Takahashi and includes > >> Andrea Righi's idea. It was posted as a part of dm-ioband which was one of > >> proposals for IO controller. > >> > > > > Does this reuse the memcg infrastructure, if so could you please add a > > summary of the changes here. > > > >> > >> (2) blkio controller modification (07/11 -- 11/11) > >> > >> The main part of blkio controller async write support. > >> Currently async queues are device-wide and async write IOs are always treated > >> as root group. > >> These patches make async queues per a cfq_group per a device to control them. > >> Async write is handled by flush kernel thread. Because queue pointers are > >> stored in cfq_io_context, io_context of the thread has to have multiple > >> cfq_io_contexts per a device. So these patches make cfq_io_context per an > >> io_context per a cfq_group, which means per an io_context per a cgroup per a > >> device. > >> > >> > >> This might be a piece of puzzle for complete async write support of blkio > >> controller. One of other pieces in my head is page dirtying ratio control. > >> I believe Andrea Righi was working on it...how about the situation? > >> > > > > Greg posted the last set of patches, we are yet to see another > > iteration. > > I am waiting to post the next iteration of memcg dirty limits and ratios until > Kame-san posts light-weight lockless update_stat(). I can post the dirty ratio > patches before the lockless updates are available, but I imagine there will be > a significant merge. So I prefer to wait, assuming that thee changes will be > coming in the near future. > will post RFC version today.
But maybe needs some sort-out..I'll CC you.
Thanks, -Kame
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