Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional adaptivespinning

From: Avi Kivity
Date: Wed Apr 07 2010 - 01:34:36 EST

On 04/06/2010 10:31 PM, Thomas Gleixner wrote:

That gives you something along the lines of

runaddr = find_run_flag(lock);
do {
while(*runaddr == RUNNING) {
if (trylock(lock))
return WHOOPEE;
cpu relax
yield (_on(thread));
That would require a new yield_to_target() syscall, which either
blocks the caller when the target thread is not runnable or returns an
error code which signals to go into the slow path.

Note, directed yield is something that kvm wants for its own ends. As an internal kernel api, not a syscall, but it's apparently useful.

Do not meddle in the internals of kernels, for they are subtle and quick to panic.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at