mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-08-28 11:49:32 +00:00
Code Issues Releases Wiki Activity

rcu/tree: Force quiescent state on callback overload

Browse source 
On callback overload, it is necessary to quickly detect idle CPUs,
and rcu_gp_fqs_check_wake() checks for this condition.  Unfortunately,
the code following the call to this function does not repeat this check,
which means that in reality no actual quiescent-state forcing, instead
only a couple of quick and pointless wakeups at the beginning of the
grace period.

This commit therefore adds a check for the RCU_GP_FLAG_OVLD flag in
the post-wakeup "if" statement in rcu_gp_fqs_loop().

Fixes: 1fca4d12f4 ("rcu: Expedite first two FQS scans under callback-overload conditions")
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Neeraj Upadhyay 2020-06-22 00:07:27 +05:30 committed by Paul E. McKenney
parent e082c7b381
commit 9c39245382
1 changed files with 1 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
kernel/rcu/tree.c
View file

@ -1884,7 +1884,7 @@ static void rcu_gp_fqs_loop(void)
break;
/* If time for quiescent-state forcing, do it. */
if (!time_after(rcu_state.jiffies_force_qs, jiffies) ||
(gf & RCU_GP_FLAG_FQS)) {
(gf & (RCU_GP_FLAG_FQS | RCU_GP_FLAG_OVLD))) {
trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
TPS("fqsstart"));
rcu_gp_fqs(first_gp_fqs);