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timers/nohz: Convert tick dependency mask to atomic_t

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The tick dependency mask was intially unsigned long because this is the
type on which clear_bit() operates on and fetch_or() accepts it.

But now that we have atomic_fetch_or(), we can instead use
atomic_andnot() to clear the bit. This consolidates the type of our
tick dependency mask, reduce its size on structures and benefit from
possible architecture optimizations on atomic_t operations.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1458830281-4255-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Frederic Weisbecker
2016-03-24 15:38:00 +01:00
committed by Ingo Molnar
parent 5acba71e18
commit f009a7a767
3 changed files with 33 additions and 34 deletions
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4
include/linux/sched.h
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@@ -720,7 +720,7 @@ struct signal_struct {
struct task_cputime cputime_expires;
#ifdef CONFIG_NO_HZ_FULL
unsigned long tick_dep_mask;
atomic_t tick_dep_mask;
#endif
struct list_head cpu_timers[3];
@@ -1549,7 +1549,7 @@ struct task_struct {
#endif
#ifdef CONFIG_NO_HZ_FULL
unsigned long tick_dep_mask;
atomic_t tick_dep_mask;
#endif
unsigned long nvcsw, nivcsw; /* context switch counts */
u64 start_time; /* monotonic time in nsec */