Re: [PATCH -tip/master 3/7] locking/mcs: Remove obsolete comment

From: Peter Zijlstra
Date: Mon Jul 28 2014 - 12:54:42 EST


On Mon, Jul 28, 2014 at 09:49:35AM -0700, Jason Low wrote:
> On Sun, 2014-07-27 at 22:18 -0700, Davidlohr Bueso wrote:
> > ... as we clearly inline mcs_spin_lock() now.
> >
> > Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx>
> > ---
> > kernel/locking/mcs_spinlock.h | 3 ---
> > 1 file changed, 3 deletions(-)
> >
> > diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h
> > index 23e89c5..4d60986 100644
> > --- a/kernel/locking/mcs_spinlock.h
> > +++ b/kernel/locking/mcs_spinlock.h
> > @@ -56,9 +56,6 @@ do { \
> > * If the lock has already been acquired, then this will proceed to spin
> > * on this node->locked until the previous lock holder sets the node->locked
> > * in mcs_spin_unlock().
> > - *
> > - * We don't inline mcs_spin_lock() so that perf can correctly account for the
> > - * time spent in this lock function.
> > */
> > static inline
> > void mcs_spin_lock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
>
> Likewise, I'm wondering if we should make this function noinline so that
> "perf can correctly account for the time spent in this lock function".

What's that about anyhow? Surely perf can see where IPs come from? DWARF
has inline support after all.

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