watchdog: simplify housekeeping affinity with the appropriate mask

housekeeping_mask gathers all the CPUs that aren't part of the nohz_full
set.  This is exactly what we want the watchdog to be affine to without
the need to use complicated cpumask operations.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index e5bb86fb0ea5fac2e05cefc80bccc0a9bf99388a..d18330fa477696c9f0e8efe808d97ca42ffe0bbc 100644 (file)
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -929,10 +929,8 @@ void __init lockup_detector_init(void)
 
 #ifdef CONFIG_NO_HZ_FULL
        if (tick_nohz_full_enabled()) {
-               if (!cpumask_empty(tick_nohz_full_mask))
-                       pr_info("Disabling watchdog on nohz_full cores by default\n");
-               cpumask_andnot(&watchdog_cpumask, cpu_possible_mask,
-                              tick_nohz_full_mask);
+               pr_info("Disabling watchdog on nohz_full cores by default\n");
+               cpumask_copy(&watchdog_cpumask, housekeeping_mask);
        } else
                cpumask_copy(&watchdog_cpumask, cpu_possible_mask);
 #else