Add missing parentheses for type cast to u64.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The 32 bit unsigned substraction (next - jiffies) in stop_hz_timer can
overflow if jiffies gets advanced between next_timer_interrupt and the read
under the xtime lock. The cast to a u64 then results in a large value
which causes the cpu to wait too long. Fix this by casting next and
jiffies independently to u64 before subtracting them.
(Spotted by Zachary Amsden <zach@vmware.com>)
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Exploit rcu_needs_cpu() interface to keep the cpu 'ticking' if necessary.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add monotonic_clock interface, used by the hangcheck-timer. On s390 this is
the same as sched_clock().
Signed-off-by: Jan Glauber <jan.glauber@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The least significant bit of the TOD clock value returned by get_clock
is the 4096th part of a microsecond. To get to nanoseconds the value
needs to be divided by 4096 and multiplied with 1000.
The current method multiplies first and then shifts the value to make the
result as precise as possible. The disadvantage is that the multiplication
with 1000 will overflow shortly after 52 days. sched_clock is used by the
scheduler for time stamp deltas, if an overflow occurs between two time stamps
the scheduler will get confused.
With the patch the problem occurs only after approx. one year, so the chance
to run into this overflow is extremly low.
Signed-off-by: Jan Glauber <jan.glauber@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
finish_arch_switch needs to update the user cpu time as well, not just the
system cpu time. Otherwise the partial user cpu time of a process that is
stored in the lowcore will be (mis-)accounted to the next process.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The calculation of the value return by next_timer_interrupt from jiffies to
jiffies_64 is racy against xtime updates. We need to protect the calculation
with read_seqbegin/read_seqretry.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Define jiffies_64 in kernel/timer.c rather than having 24 duplicated
defines in each architecture.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch cleans up a commonly repeated set of changes to the NTP state
variables by adding two helper inline functions:
ntp_clear(): Clears the ntp state variables
ntp_synced(): Returns 1 if the system is synced with a time server.
This was compile tested for alpha, arm, i386, x86-64, ppc64, s390, sparc,
sparc64.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix overflow in calculation of the new tod value in stop_hz_timer and fix
wrong virtual timer list idle time in case the virtual timer is already
expired in stop_cpu_timer.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Martin Schwidefsky
Heiko Carstens
Jan Glauber
Al Viro
Thomas Gleixner
john stultz
Linus Torvalds