lkml.org 
[lkml]   [2008]   [Oct]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/2] Allow rwlocks to re-enable interrupts
From
Date
On Wed, 2008-10-22 at 13:05 -0600, Matthew Wilcox wrote:
> On Wed, Oct 22, 2008 at 07:24:31PM +0200, Peter Zijlstra wrote:
> > > No problem. I could then also use it for _spin_lock_irqsave, if the
> > > answer to the above question is use CONFIG_LOCK_STAT there as well.
> >
> > If you create LOCK_CONTEDED_FLAGS() the whole issue goes away nicely.

Gah, I looked at it again, and that #ifdef isn't only to select between
LOCK_CONTENDED and not, but we can't actually have the re-enable for
anything lockdep.

So I was wrong.

> Should it also be used for _spin_lock_irq()? I'm puzzled why it's only
> used for _irqsave().

Right, not sure how this maze is done.

The thing is, with spin_lock_irq() you know the irq state and can do the
enable unconditionally - then again, with ticket locks we cannot do it
at all.

The _flags() version needs the flags to see if irqs was enabled before
we entered the op, if it wasn't we cannot go around enabling them.

> (should _spin_lock_bh() re-enable BHs while waiting? Is it just not big
> enough of a deal?)

Doubt it.. dunno.. personally I'd rather see softirqs die sooner rather
than later.


\
 
 \ /
  Last update: 2008-10-22 21:23    [W:0.027 / U:9.904 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site