From: Boqun Feng <boqun.feng@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>
Subject: [RFC 2/5] rcu: Use leaf_node_for_each_mask_possible_cpu() in RCU stall checking
Date: Fri, 9 Dec 2016 16:48:24 +0800 [thread overview]
Message-ID: <20161209084828.11827-3-boqun.feng@gmail.com> (raw)
In-Reply-To: <20161209084828.11827-1-boqun.feng@gmail.com>
Replace for_each_leaf_node_possible_cpu() loop with
leaf_node_for_each_mask_possible_cpu() loop to gain fewer checks in RCU
stall checking code.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
kernel/rcu/tree.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b56e2dc31ba5..5f6802b9ba5f 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1412,15 +1412,16 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp)
static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
{
int cpu;
- unsigned long flags;
+ unsigned long flags, bit;
struct rcu_node *rnp;
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
- for_each_leaf_node_possible_cpu(rnp, cpu)
- if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu))
- if (!trigger_single_cpu_backtrace(cpu))
- dump_cpu_task(cpu);
+
+ leaf_node_for_each_mask_possible_cpu(rnp, rnp->qsmask, bit, cpu)
+ if (!trigger_single_cpu_backtrace(cpu))
+ dump_cpu_task(cpu);
+
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
}
@@ -1455,6 +1456,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
{
int cpu;
long delta;
+ unsigned long bit;
unsigned long flags;
unsigned long gpa;
unsigned long j;
@@ -1490,13 +1492,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
ndetected += rcu_print_task_stall(rnp);
- if (rnp->qsmask != 0) {
- for_each_leaf_node_possible_cpu(rnp, cpu)
- if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) {
- print_cpu_stall_info(rsp, cpu);
- ndetected++;
- }
+
+ leaf_node_for_each_mask_possible_cpu(rnp, rnp->qsmask, bit, cpu) {
+ print_cpu_stall_info(rsp, cpu);
+ ndetected++;
}
+
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
--
2.10.2
next prev parent reply other threads:[~2016-12-09 8:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-09 8:48 [RFC 0/5] rcu: Introduce leaf_node_for_each_mask_possible_cpu() and its friend Boqun Feng
2016-12-09 8:48 ` [RFC 1/5] rcu: Introduce primitives to iterate mask bits in an RCU leaf node Boqun Feng
2016-12-09 8:48 ` Boqun Feng [this message]
2016-12-09 8:48 ` [RFC 3/5] rcu: Use leaf_node_for_each_mask_possible_cpu() for ->expmask iteration Boqun Feng
2016-12-09 8:48 ` [RFC 4/5] rcu: Use leaf_node_for_each_mask_possible_cpu() in force_qs_rnp() Boqun Feng
2016-12-09 8:48 ` [RFC 5/5] rcu: Use leaf_node_for_each_mask_*() for leaf node online CPU iteration Boqun Feng
2016-12-09 23:49 ` [RFC 0/5] rcu: Introduce leaf_node_for_each_mask_possible_cpu() and its friend Paul E. McKenney
2016-12-10 0:45 ` Boqun Feng
2016-12-10 4:28 ` Paul E. McKenney
2016-12-10 13:36 ` Boqun Feng
2016-12-10 17:38 ` Paul E. McKenney
2016-12-11 0:06 ` Boqun Feng
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161209084828.11827-3-boqun.feng@gmail.com \
--to=boqun.feng@gmail.com \
--cc=jiangshanlai@gmail.com \
--cc=josh@joshtriplett.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=rostedt@goodmis.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).