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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-01-06 14:11:30 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-02-21 09:03:25 -0800 |
| commit | 486e259340fc4c60474f2c14703e3b3634bb58ca (patch) | |
| tree | 70a58702194588fa0773463523f72c682785d040 /kernel/rcutree_trace.c | |
| parent | 0bb7b59d6e2b8440cd7097097dd4bbfc4d76ed07 (diff) | |
| download | lwn-486e259340fc4c60474f2c14703e3b3634bb58ca.tar.gz lwn-486e259340fc4c60474f2c14703e3b3634bb58ca.zip | |
rcu: Avoid waking up CPUs having only kfree_rcu() callbacks
When CONFIG_RCU_FAST_NO_HZ is enabled, RCU will allow a given CPU to
enter dyntick-idle mode even if it still has RCU callbacks queued.
RCU avoids system hangs in this case by scheduling a timer for several
jiffies in the future. However, if all of the callbacks on that CPU
are from kfree_rcu(), there is no reason to wake the CPU up, as it is
not a problem to defer freeing of memory.
This commit therefore tracks the number of callbacks on a given CPU
that are from kfree_rcu(), and avoids scheduling the timer if all of
a given CPU's callbacks are from kfree_rcu().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree_trace.c')
| -rw-r--r-- | kernel/rcutree_trace.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 654cfe67f0d1..db0987c1e1bd 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -73,8 +73,8 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks->dynticks_nmi_nesting, rdp->dynticks_fqs); seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, " ql=%ld qs=%c%c%c%c", - rdp->qlen, + seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c", + rdp->qlen_lazy, rdp->qlen, ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != rdp->nxttail[RCU_NEXT_TAIL]], ".R"[rdp->nxttail[RCU_WAIT_TAIL] != @@ -145,7 +145,7 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp) rdp->dynticks->dynticks_nmi_nesting, rdp->dynticks_fqs); seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi); - seq_printf(m, ",%ld,\"%c%c%c%c\"", rdp->qlen, + seq_printf(m, ",%ld,%ld,\"%c%c%c%c\"", rdp->qlen_lazy, rdp->qlen, ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != rdp->nxttail[RCU_NEXT_TAIL]], ".R"[rdp->nxttail[RCU_WAIT_TAIL] != @@ -168,7 +168,7 @@ static int show_rcudata_csv(struct seq_file *m, void *unused) { seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pgp\",\"pq\","); seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\","); - seq_puts(m, "\"of\",\"ri\",\"ql\",\"qs\""); + seq_puts(m, "\"of\",\"ri\",\"qll\",\"ql\",\"qs\""); #ifdef CONFIG_RCU_BOOST seq_puts(m, "\"kt\",\"ktl\""); #endif /* #ifdef CONFIG_RCU_BOOST */ |