this adds a read-write /proc/<pid>/smp_affinity entry,
just like what /proc/irq/<irq>/smp_affinity does,
so now we can get and set the affinity of tasks by procfs,
this is especially useful used in shell scripts.
this also adds a read-write /proc/<pid>/tasks/<tid>/smp_affinity
for the same purpose.
Cc: Eli M Dow <[EMAIL PROTECTED]>
Signed-off-by: Denis Cheng <[EMAIL PROTECTED]>
---
fs/proc/base.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 57 insertions(+), 0 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 7411bfb..ca0cbc2 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1083,6 +1083,57 @@ static const struct file_operations
proc_pid_sched_operations = {
#endif
+#ifdef CONFIG_SMP
+static ssize_t smp_affinity_read(struct file *file,
+ char __user *buf, size_t count, loff_t *ppos)
+{
+ cpumask_t mask;
+ char *page;
+ ssize_t length;
+ pid_t pid = pid_nr(proc_pid(file->f_dentry->d_inode));
+
+ length = sched_getaffinity(pid, &mask);
+ if (length < 0)
+ return length;
+
+ if (count > PROC_BLOCK_SIZE)
+ count = PROC_BLOCK_SIZE;
+
+ page = (char *)__get_free_page(GFP_TEMPORARY);
+ if (!page)
+ return -ENOMEM;
+
+ length = cpumask_scnprintf(page, count, mask);
+ length += sprintf(page + length, "\n");
+ length = simple_read_from_buffer(buf, count, ppos, page, length);
+ free_page((unsigned long) page);
+
+ return length;
+}
+
+static ssize_t smp_affinity_write(struct file *file,
+ const char __user *buf, size_t count, loff_t *ppos)
+{
+ cpumask_t mask;
+ int ret;
+ pid_t pid = pid_nr(proc_pid(file->f_dentry->d_inode));
+
+ ret = cpumask_parse_user(buf, count, mask);
+ if (ret < 0)
+ return ret;
+ ret = sched_setaffinity(pid, mask);
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+
+static const struct file_operations proc_smp_affinity_operations = {
+ .read = smp_affinity_read,
+ .write = smp_affinity_write,
+};
+#endif
+
static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
@@ -2230,6 +2281,9 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, pid_schedstat),
#endif
+#ifdef CONFIG_SMP
+ REG("smp_affinity", S_IRUGO|S_IWUSR, smp_affinity),
+#endif
#ifdef CONFIG_PROC_PID_CPUSET
REG("cpuset", S_IRUGO, cpuset),
#endif
@@ -2555,6 +2609,9 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, pid_schedstat),
#endif
+#ifdef CONFIG_SMP
+ REG("smp_affinity", S_IRUGO|S_IWUSR, smp_affinity),
+#endif
#ifdef CONFIG_PROC_PID_CPUSET
REG("cpuset", S_IRUGO, cpuset),
#endif
--
1.5.3.5
--
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