sched/debug: Move the /sys/kernel/debug/sched_features file setup into debug.c

As /sys/kernel/debug/sched_features is only created when SCHED_DEBUG is enabled, and the file
debug.c is only compiled when SCHED_DEBUG is enabled, it makes sense to move
sched_feature setup into that file and get rid of the #ifdef.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160222212825.464193063@goodmis.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 131 insertions, 0 deletions

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 7cfa87bd8b89..d2dedfcbf84d 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -16,6 +16,7 @@
 #include <linux/kallsyms.h>
 #include <linux/utsname.h>
 #include <linux/mempolicy.h>
+#include <linux/debugfs.h>
 
 #include "sched.h"
 
@@ -58,6 +59,136 @@ static unsigned long nsec_low(unsigned long long nsec)
 
 #define SPLIT_NS(x) nsec_high(x), nsec_low(x)
 
+#define SCHED_FEAT(name, enabled)       \
+        #name ,
+
+static const char * const sched_feat_names[] = {
+#include "features.h"
+};
+
+#undef SCHED_FEAT
+
+static int sched_feat_show(struct seq_file *m, void *v)
+{
+        int i;
+
+        for (i = 0; i < __SCHED_FEAT_NR; i++) {
+                if (!(sysctl_sched_features & (1UL << i)))
+                        seq_puts(m, "NO_");
+                seq_printf(m, "%s ", sched_feat_names[i]);
+        }
+        seq_puts(m, "\n");
+
+        return 0;
+}
+
+#ifdef HAVE_JUMP_LABEL
+
+#define jump_label_key__true  STATIC_KEY_INIT_TRUE
+#define jump_label_key__false STATIC_KEY_INIT_FALSE
+
+#define SCHED_FEAT(name, enabled)       \
+        jump_label_key__##enabled ,
+
+struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
+#include "features.h"
+};
+
+#undef SCHED_FEAT
+
+static void sched_feat_disable(int i)
+{
+        static_key_disable(&sched_feat_keys[i]);
+}
+
+static void sched_feat_enable(int i)
+{
+        static_key_enable(&sched_feat_keys[i]);
+}
+#else
+static void sched_feat_disable(int i) { };
+static void sched_feat_enable(int i) { };
+#endif /* HAVE_JUMP_LABEL */
+
+static int sched_feat_set(char *cmp)
+{
+        int i;
+        int neg = 0;
+
+        if (strncmp(cmp, "NO_", 3) == 0) {
+                neg = 1;
+                cmp += 3;
+        }
+
+        for (i = 0; i < __SCHED_FEAT_NR; i++) {
+                if (strcmp(cmp, sched_feat_names[i]) == 0) {
+                        if (neg) {
+                                sysctl_sched_features &= ~(1UL << i);
+                                sched_feat_disable(i);
+                        } else {
+                                sysctl_sched_features |= (1UL << i);
+                                sched_feat_enable(i);
+                        }
+                        break;
+                }
+        }
+
+        return i;
+}
+
+static ssize_t
+sched_feat_write(struct file *filp, const char __user *ubuf,
+                size_t cnt, loff_t *ppos)
+{
+        char buf[64];
+        char *cmp;
+        int i;
+        struct inode *inode;
+
+        if (cnt > 63)
+                cnt = 63;
+
+        if (copy_from_user(&buf, ubuf, cnt))
+                return -EFAULT;
+
+        buf[cnt] = 0;
+        cmp = strstrip(buf);
+
+        /* Ensure the static_key remains in a consistent state */
+        inode = file_inode(filp);
+        inode_lock(inode);
+        i = sched_feat_set(cmp);
+        inode_unlock(inode);
+        if (i == __SCHED_FEAT_NR)
+                return -EINVAL;
+
+        *ppos += cnt;
+
+        return cnt;
+}
+
+static int sched_feat_open(struct inode *inode, struct file *filp)
+{
+        return single_open(filp, sched_feat_show, NULL);
+}
+
+static const struct file_operations sched_feat_fops = {
+        .open           = sched_feat_open,
+        .write          = sched_feat_write,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static __init int sched_init_debug(void)
+{
+        debugfs_create_file("sched_features", 0644, NULL, NULL,
+                        &sched_feat_fops);
+
+        return 0;
+}
+late_initcall(sched_init_debug);
+
 #ifdef CONFIG_FAIR_GROUP_SCHED
 static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group *tg)
 {