Messages in this thread | | | Subject | Re: 2.6.24-rc6-mm1 | From | Peter Zijlstra <> | Date | Wed, 02 Jan 2008 12:24:07 +0100 |
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On Wed, 2008-01-02 at 22:12 +1100, Nick Piggin wrote: > On Wednesday 02 January 2008 22:01, Peter Zijlstra wrote:
> > I've seen 1s+ desktop latencies due to PREEMPT_BKL when I was still > > using reiserfs. > > Fair enough; so the former ifdefery would be preferable for now then.
To be honest, I must mention that the load that did that was a kernel build -j5 on a dual socket Athlon MP box. With a current kernel and XFS that load is making the box slow but its still very servicable.
> > Both reiserfs and tty were fighting for the bkl and massive prio > > inversion ensued. Turning PREEMPT_BKL off made the system usable again. > > Are either of those subsystems actually using the BKL to protect against > anything else (than themselves)?
I doubt it.
IIRC Alan is working on getting tty BKL free.
> It would be sweet to have them use > private mutexes for the job instead (although even then it probably > wouldn't be a straight conversion)...
I tried a quick conversion of reiser3 at the time, but it really wants a recursive lock and I couldn't be bothered to fix a 'legacy' filesystem so I just gave up and converted the filesystem to XFS.
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