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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2009-10-14 10:15:55 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-10-15 11:17:16 +0200 |
| commit | 37c72e56f6b234ea7387ba530434a80abf2658d8 (patch) | |
| tree | 1c589c3ecdebbe19488359795cde4c55726a63aa /kernel/rcutree.h | |
| parent | 2bc872036e1c5948b5b02942810bbdd8dbdb9812 (diff) | |
| download | linux-rt-37c72e56f6b234ea7387ba530434a80abf2658d8.tar.gz | |
rcu: Prevent RCU IPI storms in presence of high call_rcu() load
As the number of callbacks on a given CPU rises, invoke
force_quiescent_state() only every blimit number of callbacks
(defaults to 10,000), and even then only if no other CPU has
invoked force_quiescent_state() in the meantime.
This should fix the performance regression reported by Nick.
Reported-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: jens.axboe@oracle.com
LKML-Reference: <12555405592133-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcutree.h')
| -rw-r--r-- | kernel/rcutree.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h index b40ac5706040..599161f309fb 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -167,6 +167,10 @@ struct rcu_data { struct rcu_head *nxtlist; struct rcu_head **nxttail[RCU_NEXT_SIZE]; long qlen; /* # of queued callbacks */ + long qlen_last_fqs_check; + /* qlen at last check for QS forcing */ + unsigned long n_force_qs_snap; + /* did other CPU force QS recently? */ long blimit; /* Upper limit on a processed batch */ #ifdef CONFIG_NO_HZ |