sched, timers: cleanup avenrun users

avenrun is an rough estimate so we don't have to worry about
consistency of the three avenrun values. Remove the xtime lock
dependency and provide a function to scale the values. Cleanup the
users.

[ Impact: cleanup ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>

4 files changed, 28 insertions, 38 deletions

diff --git a/fs/proc/loadavg.c b/fs/proc/loadavg.c
index 9bca39cf99ee..1afa4dd4cae2 100644
--- a/fs/proc/loadavg.c
+++ b/fs/proc/loadavg.c
@@ -12,20 +12,14 @@
 
 static int loadavg_proc_show(struct seq_file *m, void *v)
 {
-        int a, b, c;
-        unsigned long seq;
+        unsigned long avnrun[3];
 
-        do {
-                seq = read_seqbegin(&xtime_lock);
-                a = avenrun[0] + (FIXED_1/200);
-                b = avenrun[1] + (FIXED_1/200);
-                c = avenrun[2] + (FIXED_1/200);
-        } while (read_seqretry(&xtime_lock, seq));
+        get_avenrun(avnrun, FIXED_1/200, 0);
 
-        seq_printf(m, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
-                LOAD_INT(a), LOAD_FRAC(a),
-                LOAD_INT(b), LOAD_FRAC(b),
-                LOAD_INT(c), LOAD_FRAC(c),
+        seq_printf(m, "%lu.%02lu %lu.%02lu %lu.%02lu %ld/%d %d\n",
+                LOAD_INT(avnrun[0]), LOAD_FRAC(avnrun[0]),
+                LOAD_INT(avnrun[1]), LOAD_FRAC(avnrun[1]),
+                LOAD_INT(avnrun[2]), LOAD_FRAC(avnrun[2]),
                 nr_running(), nr_threads,
                 task_active_pid_ns(current)->last_pid);
         return 0;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6eb4892efe45..de7b3b217772 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -116,6 +116,7 @@ struct fs_struct;
  *    11 bit fractions.
  */
 extern unsigned long avenrun[];         /* Load averages */
+extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
 
 #define FSHIFT          11              /* nr of bits of precision */
 #define FIXED_1         (1<<FSHIFT)     /* 1.0 as fixed-point */
diff --git a/kernel/sched.c b/kernel/sched.c
index f4eb88153bd1..497c09ba61e7 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2868,6 +2868,21 @@ static unsigned long calc_load_update;
 unsigned long avenrun[3];
 EXPORT_SYMBOL(avenrun);
 
+/**
+ * get_avenrun - get the load average array
+ * @loads:      pointer to dest load array
+ * @offset:     offset to add
+ * @shift:      shift count to shift the result left
+ *
+ * These values are estimates at best, so no need for locking.
+ */
+void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
+{
+        loads[0] = (avenrun[0] + offset) << shift;
+        loads[1] = (avenrun[1] + offset) << shift;
+        loads[2] = (avenrun[2] + offset) << shift;
+}
+
 static unsigned long
 calc_load(unsigned long load, unsigned long exp, unsigned long active)
 {
diff --git a/kernel/timer.c b/kernel/timer.c
index 6a21d7af9620..a26ed294f938 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1356,37 +1356,17 @@ int do_sysinfo(struct sysinfo *info)
 {
         unsigned long mem_total, sav_total;
         unsigned int mem_unit, bitcount;
-        unsigned long seq;
+        struct timespec tp;
 
         memset(info, 0, sizeof(struct sysinfo));
 
-        do {
-                struct timespec tp;
-                seq = read_seqbegin(&xtime_lock);
-
-                /*
-                 * This is annoying.  The below is the same thing
-                 * posix_get_clock_monotonic() does, but it wants to
-                 * take the lock which we want to cover the loads stuff
-                 * too.
-                 */
-
-                getnstimeofday(&tp);
-                tp.tv_sec += wall_to_monotonic.tv_sec;
-                tp.tv_nsec += wall_to_monotonic.tv_nsec;
-                monotonic_to_bootbased(&tp);
-                if (tp.tv_nsec - NSEC_PER_SEC >= 0) {
-                        tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC;
-                        tp.tv_sec++;
-                }
-                info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
+        ktime_get_ts(&tp);
+        monotonic_to_bootbased(&tp);
+        info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
 
-                info->loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
-                info->loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
-                info->loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT);
+        get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
 
-                info->procs = nr_threads;
-        } while (read_seqretry(&xtime_lock, seq));
+        info->procs = nr_threads;
 
         si_meminfo(info);
         si_swapinfo(info);