Messages in this thread |  | | Date | Tue, 8 Jan 2013 13:12:05 -0500 | From | Vivek Goyal <> | Subject | Re: [PATCH 23/24] cfq-iosched: collect stats from dead cfqgs |
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On Fri, Dec 28, 2012 at 12:35:45PM -0800, Tejun Heo wrote: > To support hierarchical stats, it's necessary to remember stats from > dead children. Add cfqg->dead_stats and make a dying cfqg transfer > its stats to the parent's dead-stats. > > The transfer happens form ->pd_offline_fn() and it is possible that > there are some residual IOs completing afterwards. Currently, we lose > these stats. Given that cgroup removal isn't a very high frequency > operation and the amount of residual IOs on offline are likely to be > nil or small, this shouldn't be a big deal and the complexity needed > to handle residual IOs - another callback and rather elaborate > synchronization to reach and lock the matching q - doesn't seem > justified. > > Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Vivek
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