[lkml]   [2013]   [Aug]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC] per-cpu preempt_count
On Tue, Aug 13, 2013 at 5:26 AM, Peter Zijlstra <> wrote:
> So we're now down to something like:
> decl fs:preempt_count
> cmpl PREEMPT_NEED_RESCHED,fs:preempt_count
> jnz 1f

Well, this isn't worth doing unless you can make PREEMPT_NEED_RESCHED
be the high bit, and we can combine it into just "decl+jns". Otherwise
we'd be better off with the simpler two separate adjacent variables.

Also, I think your patch is too big, and you should have aim to just
made the "preempt_count()" helper function mask off PREEMPT_MASK, so
that you don't change the semantics of that. I realize that there are
a couple of users that do things like "preempt_count() += x", and you
probably wanted to keep those working, but I think it is easier (and
cleaner) to fix those to "preempt_count_update(x)" instead of adding
all those explicitly PREEMPT_MASK masks.



 \ /
  Last update: 2013-08-13 18:01    [W:0.067 / U:0.292 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site