* Ingo Molnar <[email protected]> wrote:
> > * Mikulas Patocka <[email protected]> wrote: > > > The sleeping functions down, down_interruptible, down_killable and > > down_timeout can't be called with interrupts disabled, so we don't have to > > save and restore interrupt flag. > > > > This patch avoids the costly pushf and popf instructions on the semaphore > > path. > > > > Signed-off-by: Mikulas Patocka <[email protected]> > > > > --- > > kernel/locking/semaphore.c | 21 ++++++++------------- > > 1 file changed, 8 insertions(+), 13 deletions(-) > > I've applied this to the locking tree, I suspect we can do this on the > condition > that it doesn't explode in early boot code (which has irqs disabled) and > doesn't > generate early boot lockdep splats either. Hm, this blew up pretty quick on a pretty regular x86-64 PC white-box, during early bootup: PANIC: early exception 0x08 IP 246:10 error ffffffff811537b2 cr2 0xffff88000240cff8 and I think it's due to your patch - verifying that now. Thanks, Ingo
