Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH rcu 08/18] rcu: Do not disable GP stall detection in rcu_cpu_stall_reset() | Date | Wed, 21 Jul 2021 13:21:16 -0700 |
| |
From: Sergey Senozhatsky <senozhatsky@chromium.org>
rcu_cpu_stall_reset() is one of the functions virtual CPUs execute during VM resume in order to handle jiffies skew that can trigger false positive stall warnings. Paul has pointed out that this approach is problematic because rcu_cpu_stall_reset() disables RCU grace period stall-detection virtually forever, while in fact it can just restart the stall-detection timeout.
Suggested-by: "Paul E. McKenney" <paulmck@kernel.org> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- kernel/rcu/tree_stall.h | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 0e7a60706d1c0..e199022dce9dc 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -119,17 +119,14 @@ static void panic_on_rcu_stall(void) } /** - * rcu_cpu_stall_reset - prevent further stall warnings in current grace period - * - * Set the stall-warning timeout way off into the future, thus preventing - * any RCU CPU stall-warning messages from appearing in the current set of - * RCU grace periods. + * rcu_cpu_stall_reset - restart stall-warning timeout for current grace period * * The caller must disable hard irqs. */ void rcu_cpu_stall_reset(void) { - WRITE_ONCE(rcu_state.jiffies_stall, jiffies + ULONG_MAX / 2); + WRITE_ONCE(rcu_state.jiffies_stall, + jiffies + rcu_jiffies_till_stall_check()); } ////////////////////////////////////////////////////////////////////////////// -- 2.31.1.189.g2e36527f23
| |