* Esben Nielsen <[email protected]> wrote:
> [...] With your argument above ???_local_irq_disable() should really
> be preempt_disable() as that is faster.
local_irq_disable() _is_ almost the same thing as preempt_disable():
void local_irq_disable(void)
{
mask_preempt_count(IRQSOFF_MASK);
}
EXPORT_SYMBOL(local_irq_disable);
which compiles to just 4 instructions:
c012f355 <local_irq_disable>:
c012f355: b8 00 e0 ff ff mov $0xffffe000,%eax
c012f35a: 21 e0 and %esp,%eax
c012f35c: 81 48 14 00 00 00 20 orl $0x20000000,0x14(%eax)
c012f363: c3 ret
we could inline it too, that would make it exactly the same cost as
preempt_disable().
it cannot be equivalent to preempt_disable()/enable due to the semantics
of the IRQ flag. But fortunately masking/unmasking a bit is just as fast
as inc/dec.
Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
