From: Jon Hunter Date: Tue, 18 Aug 2009 17:45:11 +0000 (-0500) Subject: nohz: Allow 32-bit machines to sleep for more than 2.15 seconds X-Git-Tag: v2.6.33-rc1~363^2~7 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=97813f2fe77804a4464564c75ba8d8826377feea;p=pandora-kernel.git nohz: Allow 32-bit machines to sleep for more than 2.15 seconds In the dynamic tick code, "max_delta_ns" (member of the "clock_event_device" structure) represents the maximum sleep time that can occur between timer events in nanoseconds. The variable, "max_delta_ns", is defined as an unsigned long which is a 32-bit integer for 32-bit machines and a 64-bit integer for 64-bit machines (if -m64 option is used for gcc). The value of max_delta_ns is set by calling the function "clockevent_delta2ns()" which returns a maximum value of LONG_MAX. For a 32-bit machine LONG_MAX is equal to 0x7fffffff and in nanoseconds this equates to ~2.15 seconds. Hence, the maximum sleep time for a 32-bit machine is ~2.15 seconds, where as for a 64-bit machine it will be many years. This patch changes the type of max_delta_ns to be "u64" instead of "unsigned long" so that this variable is a 64-bit type for both 32-bit and 64-bit machines. It also changes the maximum value returned by clockevent_delta2ns() to KTIME_MAX. Hence this allows a 32-bit machine to sleep for longer than ~2.15 seconds. Please note that this patch also changes "min_delta_ns" to be "u64" too and although this is unnecessary, it makes the patch simpler as it avoids to fixup all callers of clockevent_delta2ns(). [ tglx: changed "unsigned long long" to u64 as we use this data type through out the time code ] Signed-off-by: Jon Hunter Cc: John Stultz LKML-Reference: <1250617512-23567-3-git-send-email-jon-hunter@ti.com> Signed-off-by: Thomas Gleixner --- Reading git-diff-tree failed