Messages in this thread | | | Subject | Re: [PATCH v5]: Improve performance of LZO hibernation | From | Bojan Smojver <> | Date | Wed, 28 Sep 2011 17:29:07 +1000 |
| |
On Wed, 2011-09-28 at 10:22 +0300, Pekka Enberg wrote:
> > + while(1) { > > + wait_event(d->go, atomic_read(&d->ready) || > > + kthread_should_stop()); > > + if (kthread_should_stop()) > > + break; > > So... what happens to the hibernation process when 'kthread_should_stop()' > returns true?
The compression/decompression threads stop by breaking out of the loop. At least they should, right? Did I misread some docs here?
PS. I'm not really a kernel programmer, so I'm kinda stumbling my way through all this.
> > + nthr = num_online_cpus() - 1; > > + nthr = nthr > LZO_THREADS ? LZO_THREADS : (nthr < 1 ? 1 : nthr); > > That's probably one of the most unreadable uses of the ternary > operator I've ever seen!
Sorry about that. I can simplify.
> What's going on here anyway? Why "num_online_cpus() - 1"? What's wrong with > > nr_threads = num_online_cpus(); > if (nr_threads > LZO_THREADS) > nr_threads = LZO_THREADS;
We want to keep at least one CPU free for that I/O and for pulling the other threads into sync when they are done (that is if we have more than one), right?
> [ And yes, please use less cryptic variable names. ]
OK, been pulled over for that before. Will fix.
> Overall, I really like your patch!
Thanks, hopefully it doesn't blow up too many file systems :-)
-- Bojan
| |