[PATCH 08/12] cpuset: use {cpu|node}mask pr_cont and seq output functions

From: Tejun Heo
Date: Wed Dec 10 2014 - 10:54:53 EST

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@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
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);

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

- spin_unlock(&cpuset_buffer_lock);


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