Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-02-12 Thread Paul E. McKenney
On Wed, Feb 12, 2025 at 02:14:19AM -0800, Paul E. McKenney wrote: > On Mon, Feb 10, 2025 at 08:22:24PM -0500, Joel Fernandes wrote: > > On Mon, Feb 10, 2025 at 7:28 PM Joel Fernandes > > wrote: > > > On Mon, Jan 27, 2025 at 1:45 PM Joel Fernandes > > > wrote: > > > > On Mon, Jan 27, 2025 at 11:

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-02-12 Thread Paul E. McKenney
On Mon, Feb 10, 2025 at 08:22:24PM -0500, Joel Fernandes wrote: > On Mon, Feb 10, 2025 at 7:28 PM Joel Fernandes wrote: > > On Mon, Jan 27, 2025 at 1:45 PM Joel Fernandes > > wrote: > > > On Mon, Jan 27, 2025 at 11:49 AM Paul E. McKenney > > > wrote: > > > > On Sun, Jan 26, 2025 at 09:58:11PM

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-02-10 Thread Joel Fernandes
On Mon, Feb 10, 2025 at 7:28 PM Joel Fernandes wrote: > > On Mon, Jan 27, 2025 at 1:45 PM Joel Fernandes wrote: > > > > On Mon, Jan 27, 2025 at 11:49 AM Paul E. McKenney > > wrote: > > > > > > On Sun, Jan 26, 2025 at 09:58:11PM -0500, Joel Fernandes wrote: > > > > On Sun, Jan 26, 2025 at 9:55 P

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-02-10 Thread Joel Fernandes
On Mon, Jan 27, 2025 at 1:45 PM Joel Fernandes wrote: > > On Mon, Jan 27, 2025 at 11:49 AM Paul E. McKenney wrote: > > > > On Sun, Jan 26, 2025 at 09:58:11PM -0500, Joel Fernandes wrote: > > > On Sun, Jan 26, 2025 at 9:55 PM Joel Fernandes > > > wrote: > > > > > > > > On Sun, Jan 26, 2025 at 9:

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-27 Thread Joel Fernandes
On Mon, Jan 27, 2025 at 11:49 AM Paul E. McKenney wrote: > > On Sun, Jan 26, 2025 at 09:58:11PM -0500, Joel Fernandes wrote: > > On Sun, Jan 26, 2025 at 9:55 PM Joel Fernandes > > wrote: > > > > > > On Sun, Jan 26, 2025 at 9:03 PM Paul E. McKenney > > > wrote: > > > > > > > > On Sun, Jan 26, 2

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-27 Thread Paul E. McKenney
On Sun, Jan 26, 2025 at 09:58:11PM -0500, Joel Fernandes wrote: > On Sun, Jan 26, 2025 at 9:55 PM Joel Fernandes wrote: > > > > On Sun, Jan 26, 2025 at 9:03 PM Paul E. McKenney wrote: > > > > > > On Sun, Jan 26, 2025 at 08:22:23PM -0500, Joel Fernandes wrote: > > > > On Sun, Jan 26, 2025 at 8:13 

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-26 Thread Joel Fernandes
On Sun, Jan 26, 2025 at 9:55 PM Joel Fernandes wrote: > > On Sun, Jan 26, 2025 at 9:03 PM Paul E. McKenney wrote: > > > > On Sun, Jan 26, 2025 at 08:22:23PM -0500, Joel Fernandes wrote: > > > On Sun, Jan 26, 2025 at 8:13 PM Joel Fernandes > > > wrote: > > > > > > > > Hi, Paul and Frederic, > >

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-26 Thread Joel Fernandes
On Sun, Jan 26, 2025 at 9:03 PM Paul E. McKenney wrote: > > On Sun, Jan 26, 2025 at 08:22:23PM -0500, Joel Fernandes wrote: > > On Sun, Jan 26, 2025 at 8:13 PM Joel Fernandes > > wrote: > > > > > > Hi, Paul and Frederic, > > > > > > [...] > > > > > > On Sat, Jan 25, 2025 at 12:03:58AM +0100, Fre

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-26 Thread Paul E. McKenney
On Sun, Jan 26, 2025 at 08:22:23PM -0500, Joel Fernandes wrote: > On Sun, Jan 26, 2025 at 8:13 PM Joel Fernandes wrote: > > > > Hi, Paul and Frederic, > > > > [...] > > > > > On Sat, Jan 25, 2025 at 12:03:58AM +0100, Frederic Weisbecker wrote: > > > > > > Le Fri, Dec 13, 2024 at 11:49:49AM -0800,

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-26 Thread Joel Fernandes
On Sun, Jan 26, 2025 at 8:13 PM Joel Fernandes wrote: > > Hi, Paul and Frederic, > > [...] > > > > On Sat, Jan 25, 2025 at 12:03:58AM +0100, Frederic Weisbecker wrote: > > > > > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > > > > > diff --git a/kernel/rcu/rcu.h b/kernel/

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-26 Thread Joel Fernandes
Hi, Paul and Frederic, [...] > > > On Sat, Jan 25, 2025 at 12:03:58AM +0100, Frederic Weisbecker wrote: > > > > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > > > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h > > > > > index 2f9c9272cd486..d2a91f705a4ab 100644 > > >

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-25 Thread Paul E. McKenney
On Sat, Jan 25, 2025 at 03:56:16PM +0100, Frederic Weisbecker wrote: > Le Fri, Jan 24, 2025 at 04:01:55PM -0800, Paul E. McKenney a écrit : > > On Sat, Jan 25, 2025 at 12:03:58AM +0100, Frederic Weisbecker wrote: > > > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > > > dif

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-25 Thread Frederic Weisbecker
Le Fri, Jan 24, 2025 at 04:01:55PM -0800, Paul E. McKenney a écrit : > On Sat, Jan 25, 2025 at 12:03:58AM +0100, Frederic Weisbecker wrote: > > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h > > > index 2f9c9272cd486..d2a9

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Paul E. McKenney
On Sat, Jan 25, 2025 at 12:03:58AM +0100, Frederic Weisbecker wrote: > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h > > index 2f9c9272cd486..d2a91f705a4ab 100644 > > --- a/kernel/rcu/rcu.h > > +++ b/kernel/rcu/rcu.h > > @@

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Frederic Weisbecker
Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h > index 2f9c9272cd486..d2a91f705a4ab 100644 > --- a/kernel/rcu/rcu.h > +++ b/kernel/rcu/rcu.h > @@ -162,7 +162,7 @@ static inline bool rcu_seq_done_exact(unsigned long *sp, > uns

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Paul E. McKenney
On Fri, Jan 24, 2025 at 11:25:01PM +0100, Frederic Weisbecker wrote: > Le Fri, Jan 24, 2025 at 11:40:54AM -0800, Paul E. McKenney a écrit : > > > > > I'm wondering, what prevents us from removing rcu_state.gp_seq and > > > > > rely only on > > > > > the root node for the global state ? > > > > >

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Frederic Weisbecker
Le Fri, Jan 24, 2025 at 11:40:54AM -0800, Paul E. McKenney a écrit : > > > > I'm wondering, what prevents us from removing rcu_state.gp_seq and rely > > > > only on > > > > the root node for the global state ? > > > > > > One scenario comes to mind immediately. There may be others. > > > > > >

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Paul E. McKenney
On Fri, Jan 24, 2025 at 05:42:29PM +0100, Frederic Weisbecker wrote: > Le Fri, Jan 24, 2025 at 07:58:20AM -0800, Paul E. McKenney a écrit : > > On Fri, Jan 24, 2025 at 03:49:24PM +0100, Frederic Weisbecker wrote: > > > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > > > The

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Frederic Weisbecker
Le Fri, Jan 24, 2025 at 07:58:20AM -0800, Paul E. McKenney a écrit : > On Fri, Jan 24, 2025 at 03:49:24PM +0100, Frederic Weisbecker wrote: > > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > > The get_state_synchronize_rcu_full() and poll_state_synchronize_rcu_full() > > >

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Paul E. McKenney
On Fri, Jan 24, 2025 at 03:49:24PM +0100, Frederic Weisbecker wrote: > Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > > The get_state_synchronize_rcu_full() and poll_state_synchronize_rcu_full() > > functions use the root rcu_node structure's ->gp_seq field to detect > > the

Re: [PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2025-01-24 Thread Frederic Weisbecker
Le Fri, Dec 13, 2024 at 11:49:49AM -0800, Paul E. McKenney a écrit : > The get_state_synchronize_rcu_full() and poll_state_synchronize_rcu_full() > functions use the root rcu_node structure's ->gp_seq field to detect > the beginnings and ends of grace periods, respectively. This choice is > necess

[PATCH RFC v2 rcu] Fix get_state_synchronize_rcu_full() GP-start detection

2024-12-13 Thread Paul E. McKenney
The get_state_synchronize_rcu_full() and poll_state_synchronize_rcu_full() functions use the root rcu_node structure's ->gp_seq field to detect the beginnings and ends of grace periods, respectively. This choice is necessary for the poll_state_synchronize_rcu_full() function because (give or take