Re: [PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-07 Thread Ming Lei
On Sat, Mar 7, 2015 at 5:54 AM, Dave Chinner wrote: > > If you're getting stuff there, I'd be looking for a bug in ext4, not > the rwsem code. There's no way there should be enough unwritten > extent conversion pending to lock up the system for that length of > time. Especially considering the

Re: [PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-07 Thread Ming Lei
On Sat, Mar 7, 2015 at 5:54 AM, Dave Chinner da...@fromorbit.com wrote: If you're getting stuff there, I'd be looking for a bug in ext4, not the rwsem code. There's no way there should be enough unwritten extent conversion pending to lock up the system for that length of time. Especially

Re: [PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-06 Thread Davidlohr Bueso
On Sat, 2015-03-07 at 08:54 +1100, Dave Chinner wrote: > On Fri, Mar 06, 2015 at 11:13:10PM +0800, Ming Lei wrote: > > Before commit b3fd4f03ca0b995(locking/rwsem: Avoid deceiving lock > > spinners), rwsem_spin_on_owner() returns false if the owner is changed. > > This commit just returns true

Re: [PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-06 Thread Dave Chinner
On Fri, Mar 06, 2015 at 11:13:10PM +0800, Ming Lei wrote: > Before commit b3fd4f03ca0b995(locking/rwsem: Avoid deceiving lock > spinners), rwsem_spin_on_owner() returns false if the owner is changed. > This commit just returns true under the situation, then kernel > softlock can be triggered

[PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-06 Thread Ming Lei
Before commit b3fd4f03ca0b995(locking/rwsem: Avoid deceiving lock spinners), rwsem_spin_on_owner() returns false if the owner is changed. This commit just returns true under the situation, then kernel softlock can be triggered easily in xfstest. So this patch recovers to previous behaviour, and

[PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-06 Thread Ming Lei
Before commit b3fd4f03ca0b995(locking/rwsem: Avoid deceiving lock spinners), rwsem_spin_on_owner() returns false if the owner is changed. This commit just returns true under the situation, then kernel softlock can be triggered easily in xfstest. So this patch recovers to previous behaviour, and

Re: [PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-06 Thread Dave Chinner
On Fri, Mar 06, 2015 at 11:13:10PM +0800, Ming Lei wrote: Before commit b3fd4f03ca0b995(locking/rwsem: Avoid deceiving lock spinners), rwsem_spin_on_owner() returns false if the owner is changed. This commit just returns true under the situation, then kernel softlock can be triggered easily in

Re: [PATCH -next] locking/rwsem: don't spin in heavy contention

2015-03-06 Thread Davidlohr Bueso
On Sat, 2015-03-07 at 08:54 +1100, Dave Chinner wrote: On Fri, Mar 06, 2015 at 11:13:10PM +0800, Ming Lei wrote: Before commit b3fd4f03ca0b995(locking/rwsem: Avoid deceiving lock spinners), rwsem_spin_on_owner() returns false if the owner is changed. This commit just returns true under the