Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 38/55] rcu: Prohibit grace periods during early boot | Date | Tue, 6 Sep 2011 11:00:32 -0700 |
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From: Paul E. McKenney <paul.mckenney@linaro.org>
Greater use of RCU during early boot (before the scheduler is operating) is causing RCU to attempt to start grace periods during that time, which in turn is resulting in both RCU and the callback functions attempting to use the scheduler before it is ready.
This commit prevents these problems by prohibiting RCU grace periods until after the scheduler has spawned the first non-idle task.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcutree.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 0051dbf..9970116 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -838,8 +838,11 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) struct rcu_data *rdp = this_cpu_ptr(rsp->rda); struct rcu_node *rnp = rcu_get_root(rsp); - if (!cpu_needs_another_gp(rsp, rdp) || rsp->fqs_active) { - if (cpu_needs_another_gp(rsp, rdp)) + if (!rcu_scheduler_fully_active || + !cpu_needs_another_gp(rsp, rdp) || + rsp->fqs_active) { + if (rcu_scheduler_fully_active && + cpu_needs_another_gp(rsp, rdp)) rsp->fqs_need_gp = 1; if (rnp->completed == rsp->completed) { raw_spin_unlock_irqrestore(&rnp->lock, flags); -- 1.7.3.2
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