[lkml]   [2009]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v4] introduce macro spin_event_timeout()
On Wed, Mar 11, 2009 at 3:58 PM, Benjamin Herrenschmidt
<> wrote:
> On Wed, 2009-03-11 at 13:18 -0500, Timur Tabi wrote:
>> Alan Cox wrote:
>> >> Are you talking about the udelay() inside the loop?  If so, I agree
>> >> that this is bad and have removed it in the PowerPC-specific version:
>> >
>> > The behaviour you want there is system specific - 10uS is a minimum
>> > politeness value for x86 PCI bus for example.
>> So we need to allow for delays between successive rights?  We can
>> provide that with a third parameter to the macro.
> I prefer Alan's method of having the macro be followed by { and } so we
> can add things in there. The delay between access will often be somewhat
> platform or device specific, and some drivers might be able to do useful
> things while spinning.
> The other big advantage of that approach is that drivers that aren't in
> an atomic section can use msleep() and allow the kernel to schedule on
> that processor.

Ack! I totally agree.


Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2009-03-12 03:49    [W:0.085 / U:24.644 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site