Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-30 Thread Paul E. McKenney
On Mon, Jul 29, 2013 at 05:06:43PM +1000, Dave Chinner wrote: > On Sat, Jul 27, 2013 at 04:26:28AM -0700, Paul E. McKenney wrote: > > On Sat, Jul 27, 2013 at 04:21:01PM +1000, Dave Chinner wrote: > > > On Fri, Jul 26, 2013 at 09:05:24PM -0700, Paul E. McKenney wrote: > > > > Could you please send y

Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-29 Thread Dave Chinner
On Sat, Jul 27, 2013 at 04:26:28AM -0700, Paul E. McKenney wrote: > On Sat, Jul 27, 2013 at 04:21:01PM +1000, Dave Chinner wrote: > > On Fri, Jul 26, 2013 at 09:05:24PM -0700, Paul E. McKenney wrote: > > > Could you please send your patches over to Dave Jones right now? I am > > > getting quite ti

Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-27 Thread Paul E. McKenney
On Sat, Jul 27, 2013 at 04:21:01PM +1000, Dave Chinner wrote: > On Fri, Jul 26, 2013 at 09:05:24PM -0700, Paul E. McKenney wrote: > > On Sat, Jul 27, 2013 at 12:57:03PM +1000, Dave Chinner wrote: > > > On Fri, Jul 26, 2013 at 04:28:52PM -0700, Paul E. McKenney wrote: > > > > Dave Jones reported RCU

Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-26 Thread Dave Chinner
On Fri, Jul 26, 2013 at 09:05:24PM -0700, Paul E. McKenney wrote: > On Sat, Jul 27, 2013 at 12:57:03PM +1000, Dave Chinner wrote: > > On Fri, Jul 26, 2013 at 04:28:52PM -0700, Paul E. McKenney wrote: > > > Dave Jones reported RCU stalls, overly long hrtimer interrupts, and > > > amazingly long NMI

Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-26 Thread Paul E. McKenney
On Sat, Jul 27, 2013 at 12:57:03PM +1000, Dave Chinner wrote: > On Fri, Jul 26, 2013 at 04:28:52PM -0700, Paul E. McKenney wrote: > > Dave Jones reported RCU stalls, overly long hrtimer interrupts, and > > amazingly long NMI handlers from a trinity-induced workload involving > > lots of concurrent

Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-26 Thread Dave Chinner
On Fri, Jul 26, 2013 at 04:28:52PM -0700, Paul E. McKenney wrote: > Dave Jones reported RCU stalls, overly long hrtimer interrupts, and > amazingly long NMI handlers from a trinity-induced workload involving > lots of concurrent sync() calls (https://lkml.org/lkml/2013/7/23/369). > There are any nu

Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-26 Thread Paul E. McKenney
On Fri, Jul 26, 2013 at 05:29:44PM -0700, Linus Torvalds wrote: > On Fri, Jul 26, 2013 at 4:28 PM, Paul E. McKenney > wrote: > > + > > + snap = ACCESS_ONCE(sync_seq); > > + smp_mb(); /* Prevent above from bleeding into critical section. */ > > + mutex_lock(&sync_mutex); > > +

Re: [PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-26 Thread Linus Torvalds
On Fri, Jul 26, 2013 at 4:28 PM, Paul E. McKenney wrote: > + > + snap = ACCESS_ONCE(sync_seq); > + smp_mb(); /* Prevent above from bleeding into critical section. */ > + mutex_lock(&sync_mutex); > + snap_done = ACCESS_ONCE(sync_seq); > + if (ULONG_CMP_GE(snap_done, (

[PATCH RFC fs] v2 Make sync() satisfy many requests with one invocation

2013-07-26 Thread Paul E. McKenney
Dave Jones reported RCU stalls, overly long hrtimer interrupts, and amazingly long NMI handlers from a trinity-induced workload involving lots of concurrent sync() calls (https://lkml.org/lkml/2013/7/23/369). There are any number of things that one might do to make sync() behave better under high l