Messages in this thread | | | Date | Tue, 15 Jun 2010 19:51:16 +0200 | From | Tejun Heo <> | Subject | Re: [PATCH 06/12] irq: implement irq_schedule_poll() |
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On 06/15/2010 07:40 PM, Jonathan Corbet wrote: > On Sun, 13 Jun 2010 17:31:32 +0200 > Tejun Heo <tj@kernel.org> wrote: > >> Implement and use irq_schedule_poll() to schedule desc->poll_timer >> instead of calling mod_timer directly. irq_schedule_poll() is called >> with desc->lock held and schedules the timer iff necessary - ie. if >> the timer is offline or scheduled to expire later than requested. >> This will be used to share desc->poll_timer. > > One quick question... > >> diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c >> index 0bce0e3..0b8fd0a 100644 >> --- a/kernel/irq/spurious.c >> +++ b/kernel/irq/spurious.c >> @@ -23,6 +23,8 @@ enum { >> >> /* IRQ polling common parameters */ >> IRQ_POLL_INTV = HZ / 100, /* from the good ol' 100HZ tick */ >> + >> + IRQ_POLL_SLACK = HZ / 1000, /* 10% slack */ >> }; > > Why would IRQ_POLL_SLACK be anything other than zero for HZ < 1000? > It seems like you'd get no slack at all on most systems. Am I missing > something?
Jiri questioned the same thing. I'll bump it to HZ / 250 so that it at least has one tick slack on 250HZ configuration which is pretty common these days.
Thanks.
-- tejun
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