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SubjectRe: [PATCH] Use uname not sysctl to get the kernel revision
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Ar Mer, 2006-07-12 am 16:26 -0600, ysgrifennodd Eric W. Biederman:
> If the lock is not short lived then the release is like to be a long
> ways off. If the lock is not highly contended then you are not likely
> to hit the window when someone else as the contended lock.
>
> How frequent are highly contended short lived locks in user space?

I'm not sure it matters.

If you want to do the job right then do this

- Stick an indicator of how much else wants to run on this CPU in the
vsyscall page or similar location

In your locks you can now do

while(try_and_grab_lock() == FAILED) {
if (kernelpage->waiting > 0)
sys_somelockwaitthing()
}
Furthermore the kernel can be intelligent about the waiting indicator
for power or other global scheduling reasons

[Disclaimer: There is a patent issue around this technique but its not
one that will impact GPL code as permissions are given for GPL use.]

Alan

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