On 07/25/2012 04:07 AM, Zach Brown wrote: > On Tue, Jul 24, 2012 at 05:11:05PM +0530, Ankit Jain wrote: [snip] >> With this patch, io_submit prepares all the kiocbs and then >> adds (kicks) them to ctx->run_list (kicked) in one go and then >> schedules the workqueue. The actual operations are not executed >> on io_submit's process context, so it can return very quickly. > > Strong nack; this isn't safe without having done the work to ensure that > all the task_struct references under the f_op->aio_*() paths won't be > horribly confused to find a kernel thread instead of the process that > called io_submit(). > > The one-off handling of the submitters's cred is an indication that > there might be other cases to worry about :). Makes sense, I will try to look into this. >> 3. Also, I tried not using aio_queue_work from io_submit call, and instead >> depending on an already scheduled one or the iocbs being run when >> io_getevents gets called. This seemed to give improved perfomance. But >> does this constitute as change of api semantics? > > You can't rely on io_getevents() being called for forward progress. Its > perfectly reasonable for a task to wait for io completion by polling an > eventfd that aio_complete() notifies, for instance. Ah okay, didn't realize that. Thanks, -- Ankit Jain SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
