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rcu_tree: Avoid touching rnp->completed when a new GP is started

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In rcu_gp_init(), rnp->completed equals to rsp->completed in THEORY,
we don't need to touch it normally.  If something goes wrong,
it will complain and fixup rnp->completed and avoid oops.
This commit thus avoids the normal needless store to rnp->completed.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Lai Jiangshan 2015-01-13 15:30:34 +08:00 committed by Paul E. McKenney
parent ee376dbdf2
commit 3f47da0f32
1 changed files with 2 additions and 2 deletions
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4
kernel/rcu/tree.c
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@ -1757,8 +1757,8 @@ static int rcu_gp_init(struct rcu_state *rsp)
rcu_preempt_check_blocked_tasks(rnp); rcu_preempt_check_blocked_tasks(rnp);
rnp->qsmask = rnp->qsmaskinit; rnp->qsmask = rnp->qsmaskinit;
ACCESS_ONCE(rnp->gpnum) = rsp->gpnum; ACCESS_ONCE(rnp->gpnum) = rsp->gpnum;
WARN_ON_ONCE(rnp->completed != rsp->completed); if (WARN_ON_ONCE(rnp->completed != rsp->completed))
ACCESS_ONCE(rnp->completed) = rsp->completed; ACCESS_ONCE(rnp->completed) = rsp->completed;
if (rnp == rdp->mynode) if (rnp == rdp->mynode)
(void)__note_gp_changes(rsp, rnp, rdp); (void)__note_gp_changes(rsp, rnp, rdp);
rcu_preempt_boost_start_gp(rnp); rcu_preempt_boost_start_gp(rnp);