Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U8
From: john cooper
Date: Thu Oct 21 2004 - 18:11:41 EST
Scott Wood wrote:
On Thu, Oct 21, 2004 at 06:15:00PM -0400, john cooper wrote:
Yes, but my concern was having to backoff in out-of-sequence
spinlock acquisition paths.
Out-of-sequence acquisition is a bug, unless the caller uses trylocks
and handles backoff itself.
Understood -- we may be getting hung up on terminology here.
Rather the issue was whether the nondeterministic out-of-sequence
backoff could be pushed to a noncritical path. I believe so.
It is further likely a backoff would not be needed as the
a path acquiring a mutex's task-owned list lock during a
priority promotion scan shouldn't have reason to acquire any
task's mutex-owned list lock. The latter list would only need
to be locked at time of successful mutex acquisition/free.
-john
--
john.cooper@xxxxxxxxxxx
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