Messages in this thread Patch in this message | | | From | Dmitriy Zavin <> | Subject | [PATCH 2/4] jiffies: Add 64bit jiffies compares (for use with get_jiffies_64) | Date | Thu, 21 Sep 2006 17:48:02 -0700 |
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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>
--- include/linux/jiffies.h | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h index 329ebcf..c8d5f20 100644 --- a/include/linux/jiffies.h +++ b/include/linux/jiffies.h @@ -115,6 +115,21 @@ #define time_after_eq(a,b) \ ((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. -- 1.4.2 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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