Messages in this thread | | | Date | Thu, 17 Dec 2009 17:26:03 +0800 | From | Gui Jianfeng <> | Subject | Re: [PATCH 1/4] cfq-iosced: Remove the check for same cfq group from allow_merge |
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Vivek Goyal wrote: > o allow_merge() already checks if submitting task is pointing to same cfqq > as rq has been queued in. If everything is fine, we should not be having > a task in one cgroup and having a pointer to cfqq in other cgroup. > > Well I guess in some situations it can happen and that is, when a random > IO queue has been moved into root cgroup for group_isolation=0. In > this case, tasks's cgroup/group is different from where actually cfqq is, > but this is intentional and in this case merging should be allowed. > > The second situation is where due to close cooperator patches, multiple > processes can be sharing a cfqq. If everything implemented right, we should > not end up in a situation where tasks from different processes in different > groups are sharing the same cfqq as we allow merging of cooperating queues > only if they are in same group. > > Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
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