Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-14 Thread Byungchul Park
On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > + /* > > +* Each work of workqueue might run in a different context, > > +* thanks to concurrency support of workqueue. So we have to > > +*

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-14 Thread Byungchul Park
On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > + /* > > +* Each work of workqueue might run in a different context, > > +* thanks to concurrency support of workqueue. So we have to > > +*

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-07 Thread Peter Zijlstra
On Sun, Mar 05, 2017 at 12:08:45PM +0900, Byungchul Park wrote: > On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > > > > Now the problem with the above condition is that it makes reports > > harder to decipher, because by avoiding adding redundant links to our > > graph we loose

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-07 Thread Peter Zijlstra
On Sun, Mar 05, 2017 at 12:08:45PM +0900, Byungchul Park wrote: > On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > > > > Now the problem with the above condition is that it makes reports > > harder to decipher, because by avoiding adding redundant links to our > > graph we loose

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-05 Thread Byungchul Park
On Fri, Mar 03, 2017 at 08:50:03AM +0900, Byungchul Park wrote: > On Thu, Mar 02, 2017 at 06:39:49AM -0800, Matthew Wilcox wrote: > > On Thu, Mar 02, 2017 at 01:45:35PM +0900, byungchul.park wrote: > > > From: Matthew Wilcox [mailto:wi...@infradead.org] > > > > On Tue, Feb 28, 2017 at 07:15:47PM

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-05 Thread Byungchul Park
On Fri, Mar 03, 2017 at 08:50:03AM +0900, Byungchul Park wrote: > On Thu, Mar 02, 2017 at 06:39:49AM -0800, Matthew Wilcox wrote: > > On Thu, Mar 02, 2017 at 01:45:35PM +0900, byungchul.park wrote: > > > From: Matthew Wilcox [mailto:wi...@infradead.org] > > > > On Tue, Feb 28, 2017 at 07:15:47PM

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-04 Thread Byungchul Park
On Fri, Mar 03, 2017 at 10:13:38AM +0100, Peter Zijlstra wrote: > On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > > Two boots + a make defconfig, the first didn't have the redundant bit > in, the second did (full diff below still includes the reclaim rework, > because that was

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-04 Thread Byungchul Park
On Fri, Mar 03, 2017 at 10:13:38AM +0100, Peter Zijlstra wrote: > On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > > Two boots + a make defconfig, the first didn't have the redundant bit > in, the second did (full diff below still includes the reclaim rework, > because that was

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-04 Thread Byungchul Park
On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > On Fri, Mar 03, 2017 at 09:17:37AM +0900, Byungchul Park wrote: > > On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > > > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > > > index

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-04 Thread Byungchul Park
On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > On Fri, Mar 03, 2017 at 09:17:37AM +0900, Byungchul Park wrote: > > On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > > > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > > > index

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-03 Thread Peter Zijlstra
On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > That said; I'd be fairly interested in numbers on how many links this > avoids, I'll go make a check_redundant() version of the above and put a > proper counter in so I can see what it does for a regular boot etc.. Two boots + a

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-03 Thread Peter Zijlstra
On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > That said; I'd be fairly interested in numbers on how many links this > avoids, I'll go make a check_redundant() version of the above and put a > proper counter in so I can see what it does for a regular boot etc.. Two boots + a

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-03 Thread Peter Zijlstra
On Fri, Mar 03, 2017 at 10:13:38AM +0100, Peter Zijlstra wrote: > On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > > > That said; I'd be fairly interested in numbers on how many links this > > avoids, I'll go make a check_redundant() version of the above and put a > > proper

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-03 Thread Peter Zijlstra
On Fri, Mar 03, 2017 at 10:13:38AM +0100, Peter Zijlstra wrote: > On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote: > > > That said; I'd be fairly interested in numbers on how many links this > > avoids, I'll go make a check_redundant() version of the above and put a > > proper

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-03 Thread Peter Zijlstra
On Fri, Mar 03, 2017 at 09:17:37AM +0900, Byungchul Park wrote: > On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > > index a95e5d1..7baea89 100644 > > --- a/kernel/locking/lockdep.c > > +++

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-03 Thread Peter Zijlstra
On Fri, Mar 03, 2017 at 09:17:37AM +0900, Byungchul Park wrote: > On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > > index a95e5d1..7baea89 100644 > > --- a/kernel/locking/lockdep.c > > +++

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > [*] A while ago someone, and I cannot find the email just now, asked if > we could not implement the RECLAIM_FS inversion stuff with a 'fake' lock It looks interesting to me. > like we use for other things like workqueues etc. I

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > [*] A while ago someone, and I cannot find the email just now, asked if > we could not implement the RECLAIM_FS inversion stuff with a 'fake' lock It looks interesting to me. > like we use for other things like workqueues etc. I

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 01:28:43PM +0100, Peter Zijlstra wrote: > > On Wed, Mar 01, 2017 at 02:43:23PM +0900, Byungchul Park wrote: > > > > It's an optimization, but very essential and important optimization. > > Since its not for

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 02:40:31PM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 01:28:43PM +0100, Peter Zijlstra wrote: > > On Wed, Mar 01, 2017 at 02:43:23PM +0900, Byungchul Park wrote: > > > > It's an optimization, but very essential and important optimization. > > Since its not for

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 02:41:03PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index a6c8db1..7890661 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -1042,6 +1042,19

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 02:41:03PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index a6c8db1..7890661 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -1042,6 +1042,19

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 06:39:49AM -0800, Matthew Wilcox wrote: > On Thu, Mar 02, 2017 at 01:45:35PM +0900, byungchul.park wrote: > > From: Matthew Wilcox [mailto:wi...@infradead.org] > > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > > > (And we should not be returning to

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Byungchul Park
On Thu, Mar 02, 2017 at 06:39:49AM -0800, Matthew Wilcox wrote: > On Thu, Mar 02, 2017 at 01:45:35PM +0900, byungchul.park wrote: > > From: Matthew Wilcox [mailto:wi...@infradead.org] > > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > > > (And we should not be returning to

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 01:28:43PM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 02:43:23PM +0900, Byungchul Park wrote: > > It's an optimization, but very essential and important optimization. Since its not for correctness, please put it in a separate patch with a good Changelog, the

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 01:28:43PM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 02:43:23PM +0900, Byungchul Park wrote: > > It's an optimization, but very essential and important optimization. Since its not for correctness, please put it in a separate patch with a good Changelog, the

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Matthew Wilcox
On Thu, Mar 02, 2017 at 01:45:35PM +0900, byungchul.park wrote: > From: Matthew Wilcox [mailto:wi...@infradead.org] > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > > (And we should not be returning to userspace with locks held anyway -- > > > lockdep already has a check for

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Matthew Wilcox
On Thu, Mar 02, 2017 at 01:45:35PM +0900, byungchul.park wrote: > From: Matthew Wilcox [mailto:wi...@infradead.org] > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > > (And we should not be returning to userspace with locks held anyway -- > > > lockdep already has a check for

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index a6c8db1..7890661 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1042,6 +1042,19 @@ config DEBUG_LOCK_ALLOC >spin_lock_init()/mutex_init()/etc., or

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-02 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index a6c8db1..7890661 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1042,6 +1042,19 @@ config DEBUG_LOCK_ALLOC >spin_lock_init()/mutex_init()/etc., or

RE: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread byungchul.park
name; linux- > ker...@vger.kernel.org; linux...@kvack.org; iamjoonsoo@lge.com; > a...@linux-foundation.org; npig...@gmail.com > Subject: Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > (And we should not be

RE: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread byungchul.park
name; linux- > ker...@vger.kernel.org; linux...@kvack.org; iamjoonsoo@lge.com; > a...@linux-foundation.org; npig...@gmail.com > Subject: Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > (And we should not be

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Matthew Wilcox
On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > (And we should not be returning to userspace with locks held anyway -- > lockdep already has a check for that). Don't we return to userspace with page locks held, eg during async directio?

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Matthew Wilcox
On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > (And we should not be returning to userspace with locks held anyway -- > lockdep already has a check for that). Don't we return to userspace with page locks held, eg during async directio?

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Byungchul Park
On Wed, Mar 01, 2017 at 02:17:07PM +0900, Byungchul Park wrote: > > > +void lock_commit_crosslock(struct lockdep_map *lock) > > > +{ > > > + struct cross_lock *xlock; > > > + unsigned long flags; > > > + > > > + if (!current->xhlocks) > > > + return; > > > + > > > + if

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Byungchul Park
On Wed, Mar 01, 2017 at 02:17:07PM +0900, Byungchul Park wrote: > > > +void lock_commit_crosslock(struct lockdep_map *lock) > > > +{ > > > + struct cross_lock *xlock; > > > + unsigned long flags; > > > + > > > + if (!current->xhlocks) > > > + return; > > > + > > > + if

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 02:43:23PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 02:40:18PM +0100, Peter Zijlstra wrote: > > > +static int commit_xhlocks(struct cross_lock *xlock) > > > +{ > > > + struct task_struct *curr = current; > > > + struct hist_lock *xhlock_c = xhlock_curr(curr);

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 02:43:23PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 02:40:18PM +0100, Peter Zijlstra wrote: > > > +static int commit_xhlocks(struct cross_lock *xlock) > > > +{ > > > + struct task_struct *curr = current; > > > + struct hist_lock *xhlock_c = xhlock_curr(curr);

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Byungchul Park
On Wed, Mar 01, 2017 at 11:45:48AM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 01:40:33PM +0900, Byungchul Park wrote: > > > Right. I decided to force MAX_XHLOCKS_NR to be power of 2 and everything > > became easy. Thank you very much. > > Something like: > >

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Byungchul Park
On Wed, Mar 01, 2017 at 11:45:48AM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 01:40:33PM +0900, Byungchul Park wrote: > > > Right. I decided to force MAX_XHLOCKS_NR to be power of 2 and everything > > became easy. Thank you very much. > > Something like: > >

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Byungchul Park
On Wed, Mar 01, 2017 at 11:43:28AM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 04:21:28PM +0900, Byungchul Park wrote: > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > > + /* > > > > +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Byungchul Park
On Wed, Mar 01, 2017 at 11:43:28AM +0100, Peter Zijlstra wrote: > On Wed, Mar 01, 2017 at 04:21:28PM +0900, Byungchul Park wrote: > > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > > + /* > > > > +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 01:40:33PM +0900, Byungchul Park wrote: > Right. I decided to force MAX_XHLOCKS_NR to be power of 2 and everything > became easy. Thank you very much. Something like: BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCK_NR - 1)); Should enforce I think.

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 01:40:33PM +0900, Byungchul Park wrote: > Right. I decided to force MAX_XHLOCKS_NR to be power of 2 and everything > became easy. Thank you very much. Something like: BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCK_NR - 1)); Should enforce I think.

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 04:21:28PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > + /* > > > + * Each work of workqueue might run in a different context, > > > + * thanks to

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-03-01 Thread Peter Zijlstra
On Wed, Mar 01, 2017 at 04:21:28PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > + /* > > > + * Each work of workqueue might run in a different context, > > > + * thanks to

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > + /* > > +* Each work of workqueue might run in a different context, > > +* thanks to concurrency support of workqueue. So we have to > > +*

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > + /* > > +* Each work of workqueue might run in a different context, > > +* thanks to concurrency support of workqueue. So we have to > > +*

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 01:49:06PM +0100, Peter Zijlstra wrote: > On Tue, Feb 28, 2017 at 01:45:07PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > + /* > > > + * struct held_lock does not have an indicator whether in nmi. > > > + */ > > >

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 01:49:06PM +0100, Peter Zijlstra wrote: > On Tue, Feb 28, 2017 at 01:45:07PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > + /* > > > + * struct held_lock does not have an indicator whether in nmi. > > > + */ > > >

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Wed, Mar 01, 2017 at 02:17:07PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 04:49:00PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > > > +struct cross_lock { > > > + /* > > > + * When more than one acquisition of crosslocks

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Wed, Mar 01, 2017 at 02:17:07PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 04:49:00PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > > > +struct cross_lock { > > > + /* > > > + * When more than one acquisition of crosslocks

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:40:18PM +0100, Peter Zijlstra wrote: > > +static int commit_xhlocks(struct cross_lock *xlock) > > +{ > > + struct task_struct *curr = current; > > + struct hist_lock *xhlock_c = xhlock_curr(curr); > > + struct hist_lock *xhlock = xhlock_c; > > + > > + do { > > +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:40:18PM +0100, Peter Zijlstra wrote: > > +static int commit_xhlocks(struct cross_lock *xlock) > > +{ > > + struct task_struct *curr = current; > > + struct hist_lock *xhlock_c = xhlock_curr(curr); > > + struct hist_lock *xhlock = xhlock_c; > > + > > + do { > > +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 07:29:02PM +0100, Peter Zijlstra wrote: > On Tue, Feb 28, 2017 at 10:24:44PM +0900, Byungchul Park wrote: > > On Tue, Feb 28, 2017 at 02:10:12PM +0100, Peter Zijlstra wrote: > > > > > +/* For easy access to xhlock */ > > > > +#define xhlock(t, i) ((t)->xhlocks +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 07:29:02PM +0100, Peter Zijlstra wrote: > On Tue, Feb 28, 2017 at 10:24:44PM +0900, Byungchul Park wrote: > > On Tue, Feb 28, 2017 at 02:10:12PM +0100, Peter Zijlstra wrote: > > > > > +/* For easy access to xhlock */ > > > > +#define xhlock(t, i) ((t)->xhlocks +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 04:49:00PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > +struct cross_lock { > > + /* > > +* When more than one acquisition of crosslocks are overlapped, > > +* we do actual commit only when ref == 0. > > +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 04:49:00PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > +struct cross_lock { > > + /* > > +* When more than one acquisition of crosslocks are overlapped, > > +* we do actual commit only when ref == 0. > > +

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * Each work of workqueue might run in a different context, > + * thanks to concurrency support of workqueue. So we have to > + * distinguish each work to avoid false positive. > + * > + * TODO:

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * Each work of workqueue might run in a different context, > + * thanks to concurrency support of workqueue. So we have to > + * distinguish each work to avoid false positive. > + * > + * TODO:

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Tue, Feb 28, 2017 at 10:24:44PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 02:10:12PM +0100, Peter Zijlstra wrote: > > > +/* For easy access to xhlock */ > > > +#define xhlock(t, i) ((t)->xhlocks + (i)) > > > +#define xhlock_prev(t, l)xhlock(t, idx_prev((l) -

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Tue, Feb 28, 2017 at 10:24:44PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 02:10:12PM +0100, Peter Zijlstra wrote: > > > +/* For easy access to xhlock */ > > > +#define xhlock(t, i) ((t)->xhlocks + (i)) > > > +#define xhlock_prev(t, l)xhlock(t, idx_prev((l) -

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > +struct cross_lock { > + /* > + * When more than one acquisition of crosslocks are overlapped, > + * we do actual commit only when ref == 0. > + */ > + atomic_t ref; That comment doesn't seem right, should

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > +struct cross_lock { > + /* > + * When more than one acquisition of crosslocks are overlapped, > + * we do actual commit only when ref == 0. > + */ > + atomic_t ref; That comment doesn't seem right, should

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * If the previous in held_locks can create a proper dependency > + * with a target crosslock, then we can skip commiting this, > + * since "the target crosslock -> the previous lock" and > + * "the

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * If the previous in held_locks can create a proper dependency > + * with a target crosslock, then we can skip commiting this, > + * since "the target crosslock -> the previous lock" and > + * "the

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:10:12PM +0100, Peter Zijlstra wrote: > > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > > + > > +#define idx(t) ((t)->xhlock_idx) > > +#define idx_prev(i)((i) ? (i) - 1 : MAX_XHLOCKS_NR - 1) > > +#define idx_next(i)(((i) + 1) %

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:10:12PM +0100, Peter Zijlstra wrote: > > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > > + > > +#define idx(t) ((t)->xhlock_idx) > > +#define idx_prev(i)((i) ? (i) - 1 : MAX_XHLOCKS_NR - 1) > > +#define idx_next(i)(((i) + 1) %

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:35:21PM +0100, Peter Zijlstra wrote: > On Tue, Feb 28, 2017 at 10:28:20PM +0900, Byungchul Park wrote: > > On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote: > > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > > +#define

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:35:21PM +0100, Peter Zijlstra wrote: > On Tue, Feb 28, 2017 at 10:28:20PM +0900, Byungchul Park wrote: > > On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote: > > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > > +#define

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Tue, Feb 28, 2017 at 01:45:07PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > + /* > > +* struct held_lock does not have an indicator whether in nmi. > > +*/ > > + int nmi; > > Do we really need this? Lockdep doesn't really know

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Tue, Feb 28, 2017 at 01:45:07PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > + /* > > +* struct held_lock does not have an indicator whether in nmi. > > +*/ > > + int nmi; > > Do we really need this? Lockdep doesn't really know

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Tue, Feb 28, 2017 at 10:28:20PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > +#define MAX_XHLOCKS_NR 64UL > > > > > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > > > + if

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Tue, Feb 28, 2017 at 10:28:20PM +0900, Byungchul Park wrote: > On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote: > > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > > +#define MAX_XHLOCKS_NR 64UL > > > > > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > > > + if

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > +#define MAX_XHLOCKS_NR 64UL > > > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > > + if (tsk->xhlocks) { > > + void *tmp = tsk->xhlocks; > > + /*

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Byungchul Park
On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote: > On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > > +#define MAX_XHLOCKS_NR 64UL > > > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > > + if (tsk->xhlocks) { > > + void *tmp = tsk->xhlocks; > > + /*

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > +#define MAX_XHLOCKS_NR 64UL > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > + if (tsk->xhlocks) { > + void *tmp = tsk->xhlocks; > + /* Disable crossrelease for current */ > + tsk->xhlocks = NULL; >

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > +#define MAX_XHLOCKS_NR 64UL > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > + if (tsk->xhlocks) { > + void *tmp = tsk->xhlocks; > + /* Disable crossrelease for current */ > + tsk->xhlocks = NULL; >

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
> +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > + > +#define idx(t) ((t)->xhlock_idx) > +#define idx_prev(i) ((i) ? (i) - 1 : MAX_XHLOCKS_NR - 1) > +#define idx_next(i) (((i) + 1) % MAX_XHLOCKS_NR) Note that: #define idx_prev(i) (((i) - 1) %

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
> +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > + > +#define idx(t) ((t)->xhlock_idx) > +#define idx_prev(i) ((i) ? (i) - 1 : MAX_XHLOCKS_NR - 1) > +#define idx_next(i) (((i) + 1) % MAX_XHLOCKS_NR) Note that: #define idx_prev(i) (((i) - 1) %

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * struct held_lock does not have an indicator whether in nmi. > + */ > + int nmi; Do we really need this? Lockdep doesn't really know about NMI context, so its weird to now partially introduce it.

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * struct held_lock does not have an indicator whether in nmi. > + */ > + int nmi; Do we really need this? Lockdep doesn't really know about NMI context, so its weird to now partially introduce it.

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * Each work of workqueue might run in a different context, > + * thanks to concurrency support of workqueue. So we have to > + * distinguish each work to avoid false positive. > + * > + * TODO:

Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-02-28 Thread Peter Zijlstra
On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote: > + /* > + * Each work of workqueue might run in a different context, > + * thanks to concurrency support of workqueue. So we have to > + * distinguish each work to avoid false positive. > + * > + * TODO:

[PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-01-18 Thread Byungchul Park
Lockdep is a runtime locking correctness validator that detects and reports a deadlock or its possibility by checking dependencies between locks. It's useful since it does not report just an actual deadlock but also the possibility of a deadlock that has not actually happened yet. That enables

[PATCH v5 06/13] lockdep: Implement crossrelease feature

2017-01-18 Thread Byungchul Park
Lockdep is a runtime locking correctness validator that detects and reports a deadlock or its possibility by checking dependencies between locks. It's useful since it does not report just an actual deadlock but also the possibility of a deadlock that has not actually happened yet. That enables