diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-04-07 22:47:23 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-05-02 15:09:30 -0700 |
| commit | e94698955e406f18c2936b804f867b804fa02631 (patch) | |
| tree | 1b6fa04ca1d944daf3786985b3b40a4a0cc4c68c /kernel/rcutree.c | |
| parent | ee2342d9d86b74ed9a53ff00a9cb4f76690c4b96 (diff) | |
rcu: prevent call_rcu() from diving into rcu core if irqs disabled
This commit marks a first step towards making call_rcu() have
real-time behavior. If irqs are disabled, don't dive into the
RCU core. Later on, this new early exit will wake up the
per-CPU kthread, which first must be modified to handle the
cases involving callback storms.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 963b4b1a2f77..a6fc20d98276 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1839,6 +1839,13 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), /* Add the callback to our list. */ *rdp->nxttail[RCU_NEXT_TAIL] = head; rdp->nxttail[RCU_NEXT_TAIL] = &head->next; + rdp->qlen++; + + /* If interrupts were disabled, don't dive into RCU core. */ + if (irqs_disabled_flags(flags)) { + local_irq_restore(flags); + return; + } /* * Force the grace period if too many callbacks or too long waiting. @@ -1847,7 +1854,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), * invoking force_quiescent_state() if the newly enqueued callback * is the only one waiting for a grace period to complete. */ - if (unlikely(++rdp->qlen > rdp->qlen_last_fqs_check + qhimark)) { + if (unlikely(rdp->qlen > rdp->qlen_last_fqs_check + qhimark)) { /* Are we ignoring a completed grace period? */ rcu_process_gp_end(rsp, rdp); |