ux500: add codina hotplug driver

just a current simple, geared towards u8500 cpu, early suspend hotplug driver. will look into load based hotplugging soon

Change-Id: I802c1d6c3e7caa846e10969c870452778a36b72b
slub: Push irq disable into allocate_slab()

Do the irq handling in allocate_slab() instead of __slab_alloc().

__slab_alloc() is already cluttered and allocate_slab() is already
fiddling around with gfp flags.

v6->v7:
	Only increment ORDER_FALLBACK if we get a page during fallback

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: Do not use frozen page flag but a bit in the page counters

Do not use a page flag for the frozen bit. It needs to be part
of the state that is handled with cmpxchg_double(). So use a bit
in the counter struct in the page struct for that purpose.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: Move page->frozen handling near where the page->freelist handling occurs

This is necessary because the frozen bit has to be handled in the same cmpxchg_double
with the freelist and the counters.

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
mm: Rearrange struct page

We need to be able to use cmpxchg_double on the freelist and object count
field in struct page. Rearrange the fields in struct page according to
doubleword entities so that the freelist pointer comes before the counters.
Do the rearranging with a future in mind where we use more doubleword
atomics to avoid locking of updates to flags/mapping or lru pointers.

Create another union to allow access to counters in struct page as a
single unsigned long value.

The doublewords must be properly aligned for cmpxchg_double to work.
Sadly this increases the size of page struct by one word on some architectures.
But as a resultpage structs are now cacheline aligned on x86_64.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: Add cmpxchg_double_slab()

Add a function that operates on the second doubleword in the page struct
and manipulates the object counters, the freelist and the frozen attribute.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: explicit list_lock taking

The allocator fastpath rework does change the usage of the list_lock.
Remove the list_lock processing from the functions that hide them from the
critical sections and move them into those critical sections.

This in turn simplifies the support functions (no __ variant needed anymore)
and simplifies the lock handling on bootstrap.

Inline add_partial since it becomes pretty simple.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: Pass kmem_cache struct to lock and freeze slab

We need more information about the slab for the cmpxchg implementation.

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>