path: root/kernel/rcutree.h
diff options
authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-01-04 15:09:09 -0800
committerIngo Molnar <mingo@elte.hu>2010-01-13 09:06:05 +0100
commit46a1e34eda805501a8b32f26394faa435149f6d1 (patch)
tree56359434e348fce6ffc8701fb4948dee1cb4c91f /kernel/rcutree.h
parent45f014c52eef022873b19d6a20eb0ec9668f2b09 (diff)
rcu: Make force_quiescent_state() start grace period if needed
Grace periods cannot be started while force_quiescent_state() is active. This is OK in that the affected CPUs will try again later, but it does induce needless grace-period delays. This patch causes rcu_start_gp() to record a failed attempt to start a grace period. When force_quiescent_state() prepares to return, it then starts the grace period if there was such a failed attempt. 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 LKML-Reference: <12626465501854-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcutree.h')
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index edb6fae0fa94..bd5d78ad1c48 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -278,6 +278,11 @@ struct rcu_state {
/* Force QS state. */
u8 fqs_active; /* force_quiescent_state() */
/* is running. */
+ u8 fqs_need_gp; /* A CPU was prevented from */
+ /* starting a new grace */
+ /* period because */
+ /* force_quiescent_state() */
+ /* was running. */
long gpnum; /* Current gp number. */
long completed; /* # of last completed gp. */

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