Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-09 Thread Paul E. McKenney
On Wed, Dec 09, 2020 at 10:14:49AM +0800, Boqun Feng wrote: > Hi Frederic, > > On Tue, Dec 08, 2020 at 11:04:38PM +0100, Frederic Weisbecker wrote: > > On Tue, Dec 08, 2020 at 10:24:09AM -0800, Paul E. McKenney wrote: > > > > It reduces the code scope running with BH disabled. > > > > Also

Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Boqun Feng
Hi Frederic, On Tue, Dec 08, 2020 at 11:04:38PM +0100, Frederic Weisbecker wrote: > On Tue, Dec 08, 2020 at 10:24:09AM -0800, Paul E. McKenney wrote: > > > It reduces the code scope running with BH disabled. > > > Also narrowing down helps to understand what it actually protects. > > > > I

Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Paul E. McKenney
On Tue, Dec 08, 2020 at 11:04:38PM +0100, Frederic Weisbecker wrote: > On Tue, Dec 08, 2020 at 10:24:09AM -0800, Paul E. McKenney wrote: > > > It reduces the code scope running with BH disabled. > > > Also narrowing down helps to understand what it actually protects. > > > > I thought that you

Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Frederic Weisbecker
On Tue, Dec 08, 2020 at 10:24:09AM -0800, Paul E. McKenney wrote: > > It reduces the code scope running with BH disabled. > > Also narrowing down helps to understand what it actually protects. > > I thought that you would call out unnecessarily delaying other softirq > handlers. ;-) > > But if

Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Paul E. McKenney
On Tue, Dec 08, 2020 at 06:52:30PM +0100, Frederic Weisbecker wrote: > On Tue, Dec 08, 2020 at 09:19:27AM -0800, Paul E. McKenney wrote: > > On Tue, Dec 08, 2020 at 04:54:57PM +0100, Frederic Weisbecker wrote: > > > On Tue, Dec 08, 2020 at 06:58:10AM -0800, Paul E. McKenney wrote: > > > > Hello,

Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Frederic Weisbecker
On Tue, Dec 08, 2020 at 09:19:27AM -0800, Paul E. McKenney wrote: > On Tue, Dec 08, 2020 at 04:54:57PM +0100, Frederic Weisbecker wrote: > > On Tue, Dec 08, 2020 at 06:58:10AM -0800, Paul E. McKenney wrote: > > > Hello, Frederic, > > > > > > Boqun just asked if RCU callbacks ran in BH-disabled

Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Paul E. McKenney
On Tue, Dec 08, 2020 at 04:54:57PM +0100, Frederic Weisbecker wrote: > On Tue, Dec 08, 2020 at 06:58:10AM -0800, Paul E. McKenney wrote: > > Hello, Frederic, > > > > Boqun just asked if RCU callbacks ran in BH-disabled context to avoid > > concurrent execution of the same callback. Of course,

Re: One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Frederic Weisbecker
On Tue, Dec 08, 2020 at 06:58:10AM -0800, Paul E. McKenney wrote: > Hello, Frederic, > > Boqun just asked if RCU callbacks ran in BH-disabled context to avoid > concurrent execution of the same callback. Of course, this raises the > question of whether a self-posting callback can have two

One potential issue with concurrent execution of RCU callbacks...

2020-12-08 Thread Paul E. McKenney
Hello, Frederic, Boqun just asked if RCU callbacks ran in BH-disabled context to avoid concurrent execution of the same callback. Of course, this raises the question of whether a self-posting callback can have two instances of itself running concurrently while a CPU is in the process of