On systems running with virtual cpus there is optimization potential in
regard to spinlocks and rw-locks. If the virtual cpu that has taken a lock
is known to a cpu that wants to acquire the same lock it is beneficial to
yield the timeslice of the virtual cpu in favour of the cpu that has the
lock (directed yield).
With CONFIG_PREEMPT="n" this can be implemented by the architecture without
common code changes. Powerpc already does this.
With CONFIG_PREEMPT="y" the lock loops are coded with _raw_spin_trylock,
_raw_read_trylock and _raw_write_trylock in kernel/spinlock.c. If the lock
could not be taken cpu_relax is called. A directed yield is not possible
because cpu_relax doesn't know anything about the lock. To be able to
yield the lock in favour of the current lock holder variants of cpu_relax
for spinlocks and rw-locks are needed. The new _raw_spin_relax,
_raw_read_relax and _raw_write_relax primitives differ from cpu_relax
insofar that they have an argument: a pointer to the lock structure.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes most of the issues with exported headers on CRIS, although
we do still need to deal with the asm/arch symlink.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Use the new IRQF_ constants and remove the SA_INTERRUPT define
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mikael Starvik <starvik@axis.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
cris KSTK_EIP looked for pt_regs at the right offset but from the wrong
place - forgotten ->thread_info
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Kill L1_CACHE_SHIFT from all arches. Since L1_CACHE_SHIFT_MAX is not used
anymore with the introduction of INTERNODE_CACHE, kill L1_CACHE_SHIFT_MAX.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
"extern inline" doesn't make much sense.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Mikael Starvik <starvik@axis.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
New CRIS sub architecture named v32.
From: Dave Jones <davej@redhat.com>
Fix swapped kmalloc args
Signed-off-by: Mikael Starvik <starvik@axis.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Martin Schwidefsky