Mike Rapoport [off-list ref] writes:

When a memblock allocation APIs are called with align = 0, the alignment is
implicitly set to SMP_CACHE_BYTES.

Replace all such uses of memblock APIs with the 'align' parameter explicitly
set to SMP_CACHE_BYTES and stop implicit alignment assignment in the
memblock internal allocation functions.

For the case when memblock APIs are used via helper functions, e.g. like
iommu_arena_new_node() in Alpha, the helper functions were detected with
Coccinelle's help and then manually examined and updated where appropriate.

The direct memblock APIs users were updated using the semantic patch below:

@@
expression size, min_addr, max_addr, nid;
@@
(
|
- memblock_alloc_try_nid_raw(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid_raw(size, SMP_CACHE_BYTES, min_addr, max_addr,
nid)
|
- memblock_alloc_try_nid_nopanic(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid_nopanic(size, SMP_CACHE_BYTES, min_addr, max_addr,
nid)
|
- memblock_alloc_try_nid(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid(size, SMP_CACHE_BYTES, min_addr, max_addr, nid)
|
- memblock_alloc(size, 0)
+ memblock_alloc(size, SMP_CACHE_BYTES)
|
- memblock_alloc_raw(size, 0)
+ memblock_alloc_raw(size, SMP_CACHE_BYTES)
|
- memblock_alloc_from(size, 0, min_addr)
+ memblock_alloc_from(size, SMP_CACHE_BYTES, min_addr)
|
- memblock_alloc_nopanic(size, 0)
+ memblock_alloc_nopanic(size, SMP_CACHE_BYTES)
|
- memblock_alloc_low(size, 0)
+ memblock_alloc_low(size, SMP_CACHE_BYTES)
|
- memblock_alloc_low_nopanic(size, 0)
+ memblock_alloc_low_nopanic(size, SMP_CACHE_BYTES)
|
- memblock_alloc_from_nopanic(size, 0, min_addr)
+ memblock_alloc_from_nopanic(size, SMP_CACHE_BYTES, min_addr)
|
- memblock_alloc_node(size, 0, nid)
+ memblock_alloc_node(size, SMP_CACHE_BYTES, nid)
)

Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Mike Rapoport <redacted>
---

...

 arch/powerpc/kernel/pci_32.c              |  3 ++-
 arch/powerpc/lib/alloc.c                  |  2 +-
 arch/powerpc/mm/mmu_context_nohash.c      |  7 +++---
 arch/powerpc/platforms/powermac/nvram.c   |  2 +-
 arch/powerpc/platforms/powernv/pci-ioda.c |  6 ++---
 arch/powerpc/sysdev/msi_bitmap.c          |  2 +-

The powerpc changes all look fine.

I'm not quite clear on how SMP_CACHE_BYTES is getting included.

I think it's: memblock.h -> mm.h -> mmzone.h -> cache.h

So that's probably fine.

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)


cheers