sched: /debug/sched_features
provide a text based interface to the scheduler features; this saves the
'user' from setting bits using decimal arithmetic.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 8f03817..b59a44e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -68,6 +68,8 @@
#include <linux/hrtimer.h>
#include <linux/tick.h>
#include <linux/bootmem.h>
+#include <linux/debugfs.h>
+#include <linux/ctype.h>
#include <asm/tlb.h>
#include <asm/irq_regs.h>
@@ -732,32 +734,148 @@
/*
* Debugging: various feature bits
*/
+
+#define SCHED_FEAT(name, enabled) \
+ __SCHED_FEAT_##name ,
+
enum {
- SCHED_FEAT_NEW_FAIR_SLEEPERS = 1,
- SCHED_FEAT_WAKEUP_PREEMPT = 2,
- SCHED_FEAT_START_DEBIT = 4,
- SCHED_FEAT_AFFINE_WAKEUPS = 8,
- SCHED_FEAT_CACHE_HOT_BUDDY = 16,
- SCHED_FEAT_SYNC_WAKEUPS = 32,
- SCHED_FEAT_HRTICK = 64,
- SCHED_FEAT_DOUBLE_TICK = 128,
- SCHED_FEAT_NORMALIZED_SLEEPER = 256,
- SCHED_FEAT_DEADLINE = 512,
+#include "sched_features.h"
};
-const_debug unsigned int sysctl_sched_features =
- SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 |
- SCHED_FEAT_WAKEUP_PREEMPT * 1 |
- SCHED_FEAT_START_DEBIT * 1 |
- SCHED_FEAT_AFFINE_WAKEUPS * 1 |
- SCHED_FEAT_CACHE_HOT_BUDDY * 1 |
- SCHED_FEAT_SYNC_WAKEUPS * 1 |
- SCHED_FEAT_HRTICK * 1 |
- SCHED_FEAT_DOUBLE_TICK * 0 |
- SCHED_FEAT_NORMALIZED_SLEEPER * 1 |
- SCHED_FEAT_DEADLINE * 1;
+#undef SCHED_FEAT
-#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
+#define SCHED_FEAT(name, enabled) \
+ (1UL << __SCHED_FEAT_##name) * enabled |
+
+const_debug unsigned int sysctl_sched_features =
+#include "sched_features.h"
+ 0;
+
+#undef SCHED_FEAT
+
+#ifdef CONFIG_SCHED_DEBUG
+#define SCHED_FEAT(name, enabled) \
+ #name ,
+
+__read_mostly char *sched_feat_names[] = {
+#include "sched_features.h"
+ NULL
+};
+
+#undef SCHED_FEAT
+
+int sched_feat_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+ return 0;
+}
+
+static ssize_t
+sched_feat_read(struct file *filp, char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char *buf;
+ int r = 0;
+ int len = 0;
+ int i;
+
+ for (i = 0; sched_feat_names[i]; i++) {
+ len += strlen(sched_feat_names[i]);
+ len += 4;
+ }
+
+ buf = kmalloc(len + 2, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ for (i = 0; sched_feat_names[i]; i++) {
+ if (sysctl_sched_features & (1UL << i))
+ r += sprintf(buf + r, "%s ", sched_feat_names[i]);
+ else
+ r += sprintf(buf + r, "no_%s ", sched_feat_names[i]);
+ }
+
+ r += sprintf(buf + r, "\n");
+ WARN_ON(r >= len + 2);
+
+ r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+
+ kfree(buf);
+
+ return r;
+}
+
+static ssize_t
+sched_feat_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char buf[64];
+ char *cmp = buf;
+ int neg = 0;
+ int i;
+
+ if (cnt > 63)
+ cnt = 63;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ buf[cnt] = 0;
+
+ if (strncmp(buf, "no_", 3) == 0) {
+ neg = 1;
+ cmp += 3;
+ }
+
+ for (i = 0; sched_feat_names[i]; i++) {
+ int len = strlen(sched_feat_names[i]);
+
+ if (strncmp(cmp, sched_feat_names[i], len) == 0) {
+ if (neg)
+ sysctl_sched_features &= ~(1UL << i);
+ else
+ sysctl_sched_features |= (1UL << i);
+ break;
+ }
+ }
+
+ if (!sched_feat_names[i])
+ return -EINVAL;
+
+ filp->f_pos += cnt;
+
+ return cnt;
+}
+
+static struct file_operations sched_feat_fops = {
+ .open = sched_feat_open,
+ .read = sched_feat_read,
+ .write = sched_feat_write,
+};
+
+static __init int sched_init_debug(void)
+{
+ int i, j, len;
+
+ for (i = 0; sched_feat_names[i]; i++) {
+ len = strlen(sched_feat_names[i]);
+
+ for (j = 0; j < len; j++) {
+ sched_feat_names[i][j] =
+ tolower(sched_feat_names[i][j]);
+ }
+ }
+
+ debugfs_create_file("sched_features", 0644, NULL, NULL,
+ &sched_feat_fops);
+
+ return 0;
+}
+late_initcall(sched_init_debug);
+
+#endif
+
+#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
/*
* Number of tasks to iterate in a single balance run.
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
new file mode 100644
index 0000000..1c7283c
--- /dev/null
+++ b/kernel/sched_features.h
@@ -0,0 +1,10 @@
+SCHED_FEAT(NEW_FAIR_SLEEPERS, 1)
+SCHED_FEAT(WAKEUP_PREEMPT, 1)
+SCHED_FEAT(START_DEBIT, 1)
+SCHED_FEAT(AFFINE_WAKEUPS, 1)
+SCHED_FEAT(CACHE_HOT_BUDDY, 1)
+SCHED_FEAT(SYNC_WAKEUPS, 1)
+SCHED_FEAT(HRTICK, 1)
+SCHED_FEAT(DOUBLE_TICK, 0)
+SCHED_FEAT(NORMALIZED_SLEEPER, 1)
+SCHED_FEAT(DEADLINE, 1)
