mirrors/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2025-10-31 16:48:26 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

rcu: Do not disable GP stall detection in rcu_cpu_stall_reset()

Browse source 
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>
This commit is contained in:
Sergey Senozhatsky 2021-05-22 00:56:24 +09:00 committed by Paul E. McKenney
parent ccfc9dd691
commit a80be428fb
1 changed files with 3 additions and 6 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
kernel/rcu/tree_stall.h
View file

@ -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());
}
//////////////////////////////////////////////////////////////////////////////