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Commit 68107df5 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

u64_stats: Introduce IRQs disabled helpers 



Introduce light versions of u64_stats helpers for context where
either preempt or IRQs are disabled. This way we can make this library
usable by scheduler irqtime accounting which currenty implement its
ad-hoc version.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1474849761-12678-4-git-send-email-fweisbec@gmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2810f611

include/linux/u64_stats_sync.h

+24 −21
Original line number Original line Diff line number Diff line
@@ -103,31 +103,42 @@ static inline void u64_stats_update_end_raw(struct u64_stats_sync *syncp) 
#endif

#endif

}

}





static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *syncp)

static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *syncp)

{

{

#if BITS_PER_LONG==32 && defined(CONFIG_SMP)

#if BITS_PER_LONG==32 && defined(CONFIG_SMP)

	return read_seqcount_begin(&syncp->seq);

	return read_seqcount_begin(&syncp->seq);

#else

#else

#if BITS_PER_LONG==32

	preempt_disable();

#endif

	return 0;

	return 0;

#endif

#endif

}

}





static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,

static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *syncp)

{

#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)

	preempt_disable();

#endif

	return __u64_stats_fetch_begin(syncp);

}



static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp,

					 unsigned int start)

					 unsigned int start)

{

{

#if BITS_PER_LONG==32 && defined(CONFIG_SMP)

#if BITS_PER_LONG==32 && defined(CONFIG_SMP)

	return read_seqcount_retry(&syncp->seq, start);

	return read_seqcount_retry(&syncp->seq, start);

#else

#else

#if BITS_PER_LONG==32

	preempt_enable();

#endif

	return false;

	return false;

#endif

#endif

}

}





static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,

					 unsigned int start)

{

#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)

	preempt_enable();

#endif

	return __u64_stats_fetch_retry(syncp, start);

}



/*

/*

 * In case irq handlers can update u64 counters, readers can use following helpers

 * In case irq handlers can update u64 counters, readers can use following helpers

 * - SMP 32bit arches use seqcount protection, irq safe.

 * - SMP 32bit arches use seqcount protection, irq safe.
@@ -136,27 +147,19 @@ static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp, 
 */

 */

static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync *syncp)

static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync *syncp)

{

{

#if BITS_PER_LONG==32 && defined(CONFIG_SMP)

#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)

	return read_seqcount_begin(&syncp->seq);

#else

#if BITS_PER_LONG==32

	local_irq_disable();

	local_irq_disable();

#endif

#endif

	return 0;

	return __u64_stats_fetch_begin(syncp);

#endif

}

}





static inline bool u64_stats_fetch_retry_irq(const struct u64_stats_sync *syncp,

static inline bool u64_stats_fetch_retry_irq(const struct u64_stats_sync *syncp,

					     unsigned int start)

					     unsigned int start)

{

{

#if BITS_PER_LONG==32 && defined(CONFIG_SMP)

#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)

	return read_seqcount_retry(&syncp->seq, start);

#else

#if BITS_PER_LONG==32

	local_irq_enable();

	local_irq_enable();

#endif

#endif

	return false;

	return __u64_stats_fetch_retry(syncp, start);

#endif

}

}





#endif /* _LINUX_U64_STATS_SYNC_H */
 
#endif /* _LINUX_U64_STATS_SYNC_H */