linux.git/arch/s390/lib, branch v3.18.74

s390/uprobes: fix kprobes dependency

2014-10-17T12:45:51+00:00

If kprobes is disabled uprobes will not compile.
Fix this by including the correct header files.

Signed-off-by: Jan Willeke 
Signed-off-by: Martin Schwidefsky

s390/idle: consolidate idle functions and definitions

2014-10-09T07:14:03+00:00

Move the C functions and definitions related to the idle state handling
to arch/s390/include/asm/idle.h and arch/s390/kernel/idle.c. The function
s390_get_idle_time is renamed to arch_cpu_idle_time and vtime_stop_cpu to
enabled_wait.

Signed-off-by: Martin Schwidefsky

s390/uprobes: common library for kprobes and uprobes

2014-09-25T08:52:14+00:00

This patch moves common functions from kprobes.c to probes.c.
Thus its possible for uprobes to use them without enabling kprobes.

Signed-off-by: Jan Willeke 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/rwlock: use the interlocked-access facility 1 instructions

2014-09-25T08:52:13+00:00

Make use of the load-and-add, load-and-or and load-and-and instructions
to atomically update the read-write lock without a compare-and-swap loop.

Signed-off-by: Martin Schwidefsky

s390/rwlock: improve writer fairness

2014-09-25T08:52:12+00:00

Set the write-lock bit in the out-of-line rwlock code to indicate that
a writer is waiting. Additional readers will no be able to get the lock
until at least one writer got the lock. Additional writers have to wait
for the first writer to release the lock again.

Signed-off-by: Martin Schwidefsky

s390/rwlock: remove interrupt-enabling rwlock variant.

2014-09-25T08:52:10+00:00

Signed-off-by: Martin Schwidefsky

s390/rwlock: use directed yield for write-locked rwlocks

2014-09-25T08:52:05+00:00

Add an owner field to the arch_rwlock_t to be able to pass the timeslice
of a virtual CPU with diagnose 0x9c to the lock owner in case the rwlock
is write-locked. The undirected yield in case the rwlock is acquired
writable but the lock is read-locked is removed.

Signed-off-by: Martin Schwidefsky

s390/spinlock: refactor arch_spin_lock_wait[_flags]

2014-05-20T06:58:55+00:00

Reorder the spinlock wait code to make it more readable.

Signed-off-by: Martin Schwidefsky

s390/rwlock: add missing local_irq_restore calls

2014-05-20T06:58:54+00:00

The out of line _raw_read_lock_wait_flags/_raw_write_lock_wait_flags
functions for the arch_read_lock_flags/arch_write_lock_flags  calls
fail to re-enable the interrupts after another unsuccessful try to
get the lock with compare-and-swap. The following wait would be
done with interrupts disabled which is suboptimal.

Signed-off-by: Martin Schwidefsky

s390/spinlock,rwlock: always to a load-and-test first

2014-05-20T06:58:53+00:00

In case a lock is contended it is better to do a load-and-test first
before trying to get the lock with compare-and-swap. This helps to avoid
unnecessary cache invalidations of the cacheline for the lock if the
CPU has to wait for the lock. For an uncontended lock doing the
compare-and-swap directly is a bit better, if the CPU does not have the
cacheline in its cache yet the compare-and-swap will get it read-write
immediately while a load-and-test would get it read-only first.

Always to the load-and-test first to avoid the cacheline invalidations
for the contended case outweight the potential read-only to read-write
cacheline upgrade for the uncontended case.

Signed-off-by: Martin Schwidefsky