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linux/include
Jon Hunter 97813f2fe7 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 <jon-hunter@ti.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <1250617512-23567-3-git-send-email-jon-hunter@ti.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-13 20:46:24 +01:00
..
acpi ACPI: remove acpi_device_uid() and related stuff 2009-09-25 15:09:49 -04:00
asm-generic asm-generic/gpio.h: pull in linux/kernel.h for might_sleep() 2009-10-01 16:11:11 -07:00
crypto
drm Merge branch 'drm-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2009-09-30 08:03:00 -07:00
keys
linux nohz: Allow 32-bit machines to sleep for more than 2.15 seconds 2009-11-13 20:46:24 +01:00
math-emu
media
mtd
net net: Make setsockopt() optlen be unsigned. 2009-09-30 16:12:20 -07:00
pcmcia PM / PCMCIA: Drop second argument of pcmcia_socket_dev_suspend() 2009-09-29 00:10:41 +02:00
rdma
rxrpc
scsi
sound
trace Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2009-09-30 09:32:30 -07:00
video davinci-fb-frame-buffer-driver-for-ti-da8xx-omap-l1xx-v4 2009-09-23 07:39:51 -07:00
xen
Kbuild