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Commit 0d95092c authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Fix outdated rcu_scheduler_active comment 



The comment header for rcu_scheduler_active states that it is used
to optimize synchronize_sched() at early boot.  This is incorrect.
The synchronize_sched() function instead checks the number of online
CPUs.  This commit therefore replaces the comment's synchronize_sched()
with synchronize_rcu(), which really does use rcu_scheduler_active for
this purpose.

Reported-by: default avatarLihao Liang <lihao.liang@gmail.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent af8c34ce

kernel/rcu/tree.c

+1 −1
Original line number Diff line number Diff line
@@ -130,7 +130,7 @@ int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */ 
 * The rcu_scheduler_active variable transitions from zero to one just

 * before the first task is spawned.  So when this variable is zero, RCU

 * can assume that there is but one task, allowing RCU to (for example)

 * optimize synchronize_sched() to a simple barrier().  When this variable

 * optimize synchronize_rcu() to a simple barrier().  When this variable

 * is one, RCU must actually do all the hard work required to detect real

 * grace periods.  This variable is also used to suppress boot-time false

 * positives from lockdep-RCU error checking.