Re: [RFC PATCH] hrtimer: removing all ur callback modes

From: Oliver Hartkopp
Date: Sun Dec 07 2008 - 06:22:40 EST


Peter Zijlstra wrote:
On Tue, 2008-11-25 at 12:43 +0100, Peter Zijlstra wrote:
Hi,

This is an attempt at removing some of the hrtimer complexity by
reducing the number of callback modes to 1.

This means that all hrtimer callback functions will be ran from HARD-irq
context.

I went through all the 30 odd hrtimer callback functions in the kernel
and saw only one that I'm not quite sure of, which is the one in
net/can/bcm.c - hence I'm CC-ing the folks responsible for that code.

Thanks Peter.

Indeed i assumed my hrtimer callbacks to run in soft-irq. I tried the can-bcm protocol with Ingos current linux-2.6-sched-devel.git including your patches and i did not see any issues so far. And i do not expect any (recursion) problems with hrtimer_forward() in my code either.

But i'm not that familiar with the timer context's stuff, that i would like guaranty that the functions i use in bcm_send_user() and in bcm_can_tx() are always safe to be used in hard-irq context.

It would be nice, if you could give me some support by double checking the correctness of the hard-irq context in the given functions.

Best regards,
Oliver

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