Re: [PATCH] memblock: stop using implicit alignement to SMP_CACHE_BYTES

Michael Ellerman
2018-10-10T12:04:12Z

Mike Rapoport <rppt@linux.vnet.ibm.com> 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 <rppt@linux.vnet.ibm.com>
> ---
...
> 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