linux-kernel - [PATCH 08/12] cpuset: use {cpu|node}mask pr

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Message-Id: <1418226774-30215-9-git-send-email-tj@kernel.org>
Date:	Wed, 10 Dec 2014 10:52:50 -0500
From:	Tejun Heo <tj@...nel.org>
To:	akpm@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org, Tejun Heo <tj@...nel.org>,
	Li Zefan <lizefan@...wei.com>
Subject: [PATCH 08/12] cpuset: use {cpu|node}mask pr_cont and seq output functions

Convert the existing user of cpu{mask|list}_scnprintf() and
node{mask|list}_scnprintf() which use them just to printk or
seq_printf() the resulting buffer to use the following functions
instead respectively.

* For printk: cpu{mask|list}_pr_cont() and node{mask|list}_pr_cont().

* For seq_file: seq_cpumask[_list]() and seq_nodemask[_list]().

Because these conversions usually break up a single output function
call into multiple, the reduction is LOC isn't too big but it removes
unnecessary complexity and/or arbitrary limit on the length printed.

* kernel/cpuset.c::cpuset_print_task_mems_allowed() used a static
  buffer which is protected by a dedicated spinlock.  Replaced with
  plain pr_conts.

This patch is dependent on the previous patch ("bitmap, cpumask,
nodemask: implement pr_cont variants of formatting functions") which
is planned to go through -mm.  It'd be the easiest to route this
together.  If this should go through the subsystem tree, please wait
till the forementioned patch is merged to mainline.

Signed-off-by: Tejun Heo <tj@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Li Zefan <lizefan@...wei.com>
---
 kernel/cpuset.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index fdf1759..6a7f466 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2614,8 +2614,6 @@ int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
 	return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
 }

-#define CPUSET_NODELIST_LEN	(256)
-
 /**
  * cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed
  * @tsk: pointer to task_struct of some task.
@@ -2625,23 +2623,18 @@ int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
  */
 void cpuset_print_task_mems_allowed(struct task_struct *tsk)
 {
-	 /* Statically allocated to prevent using excess stack. */
-	static char cpuset_nodelist[CPUSET_NODELIST_LEN];
-	static DEFINE_SPINLOCK(cpuset_buffer_lock);
 	struct cgroup *cgrp;

-	spin_lock(&cpuset_buffer_lock);
 	rcu_read_lock();

 	cgrp = task_cs(tsk)->css.cgroup;
-	nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
-			   tsk->mems_allowed);
 	pr_info("%s cpuset=", tsk->comm);
 	pr_cont_cgroup_name(cgrp);
-	pr_cont(" mems_allowed=%s\n", cpuset_nodelist);
+	pr_cont(" mems_allowed=");
+	nodelist_pr_cont(tsk->mems_allowed);
+	pr_cont("\n");

 	rcu_read_unlock();
-	spin_unlock(&cpuset_buffer_lock);
 }

 /*
-- 
2.1.0

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