[PATCH] Add 64bit jiffies compares (for use with get_jiffies_64) (3b171672) · Commits · 戴 / test

The current time_before/time_after macros will fail typechecks when passed u64 values (as returned by get_jiffies_64()). On 64bit systems, this will just result in a warning about mismatching types without explicit casts, but since unsigned long and u64 (unsigned long long) are of same size, it will still work. On 32bit systems, a long is 32bits, so the value from get_jiffies_64() will be truncated by the cast and thus lose all the precision gained by 64bit jiffies. Signed-off-by:

Dmitriy Zavin <dmitriyz@google.com> Signed-off-by:

Andi Kleen <ak@suse.de>

include/linux/jiffies.h

+15 −0

Original line number	Diff line number	Diff line
		@@ -115,6 +115,21 @@ static inline u64 get_jiffies_64(void)
		((long)(a) - (long)(b) >= 0))
		#define time_before_eq(a,b) time_after_eq(b,a)

		/* Same as above, but does so with platform independent 64bit types.
		* These must be used when utilizing jiffies_64 (i.e. return value of
		* get_jiffies_64() */
		#define time_after64(a,b) \
		(typecheck(__u64, a) && \
		typecheck(__u64, b) && \
		((__s64)(b) - (__s64)(a) < 0))
		#define time_before64(a,b) time_after64(b,a)

		#define time_after_eq64(a,b) \
		(typecheck(__u64, a) && \
		typecheck(__u64, b) && \
		((__s64)(a) - (__s64)(b) >= 0))
		#define time_before_eq64(a,b) time_after_eq64(b,a)

		/*
		* Have the 32 bit jiffies value wrap 5 minutes after boot
		* so jiffies wrap bugs show up earlier.

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