Messages in this thread | | | Date | Thu, 8 Oct 2009 10:36:09 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH 18/45] writeback: introduce wait queue for balance_dirty_pages() |
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On Thu, Oct 08 2009, Peter Zijlstra wrote: > On Thu, 2009-10-08 at 09:58 +0800, Wu Fengguang wrote: > > > > > How this runqueue->nr_iowait is handled now ? > > > > Good question. io_schedule() has an old comment for throttling IO wait: > > > > * But don't do that if it is a deliberate, throttling IO wait (this task > > * has set its backing_dev_info: the queue against which it should throttle) > > */ > > void __sched io_schedule(void) > > > > So it looks both Jens' and this patch behaves right in ignoring the > > iowait accounting for balance_dirty_pages() :) > > Well it is a change in behaviour, and I think IOWAIT makes sense when > we're blocked due to io throttle.. > > Hmm?
Yep agree, if we're deliberately waiting on IO, it should count as iowait time.
-- Jens Axboe
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