[dm-devel] [PATCH] dm-bufio
Joe Thornber
thornber at redhat.com
Mon Oct 17 14:15:22 UTC 2011
On Mon, Oct 17, 2011 at 10:04:16AM -0400, Mikulas Patocka wrote:
> > If you're going to use cond_resched() at least do so a little more
> > intelligently than putting it in _every_ loop. For instance you call it on
> > every iteration of a sweep through the hash table. The call to
> > cond_resched will take more time than the loop body. At least make a
> > change so it's only done every n'th iteration.
>
> I think it would be better to use
> #ifndef CONFIG_PREEMPT
> if (need_resched()) cond_resched();
> #endif
>
> need_resched() is inlined and translates to a single condition.
Yep, that would be fine.
> I don't know why Linux doesn't provide a macro for it, this would be
> useful far beyond dm code.
Agreed, I was very surprised that cond_resched() expands out to a
function call rather than a test + fn call.
Get a patch together and I'll merge.
- Joe
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