Messages in this thread | | | Date | Thu, 28 May 2009 18:27:40 +0900 (JST) | Subject | Re: [PATCH 15/20] io-controller: map async requests to appropriate cgroup | From | Ryo Tsuruta <> |
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Hi Vivek,
> +#ifdef CONFIG_TRACK_ASYNC_CONTEXT > + if (elv_bio_sync(bio)) { > + /* sync io. Determine cgroup from submitting task context. */ > + cgroup = task_cgroup(current, io_subsys_id); > + return cgroup; > + } > + > + /* Async io. Determine cgroup from with cgroup id stored in page */ > + bio_cgroup_id = get_blkio_cgroup_id(bio); > + > + if (!bio_cgroup_id) > + return NULL; > + > + cgroup = blkio_cgroup_lookup(bio_cgroup_id); > +#else > + cgroup = task_cgroup(current, io_subsys_id); > +#endif > + return cgroup; > +}
There is a case where a kernel thread (such as device-mapper drivers) submits a sync IO instead of a task which originates the IO. I think you should always use get_blkio_cgroup_id() to determine cgroup.
Thanks, Ryo Tsuruta
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