diff options
| author | David Hildenbrand | 2022-03-22 14:43:17 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2022-03-22 15:57:05 -0700 |
| commit | e16faf26780fc0c8dd693ea9ee8420a7706cb2f5 (patch) | |
| tree | 552264c77a30bda6176337f66086a5067dcd5146 /arch | |
| parent | 566513775dca7f0d4ba15da4bc8394cdb2c98829 (diff) | |
cma: factor out minimum alignment requirement
Patch series "mm: enforce pageblock_order < MAX_ORDER".
Having pageblock_order >= MAX_ORDER seems to be able to happen in corner
cases and some parts of the kernel are not prepared for it.
For example, Aneesh has shown [1] that such kernels can be compiled on
ppc64 with 64k base pages by setting FORCE_MAX_ZONEORDER=8, which will
run into a WARN_ON_ONCE(order >= MAX_ORDER) in comapction code right
during boot.
We can get pageblock_order >= MAX_ORDER when the default hugetlb size is
bigger than the maximum allocation granularity of the buddy, in which
case we are no longer talking about huge pages but instead gigantic
pages.
Having pageblock_order >= MAX_ORDER can only make alloc_contig_range()
of such gigantic pages more likely to succeed.
Reliable use of gigantic pages either requires boot time allcoation or
CMA, no need to overcomplicate some places in the kernel to optimize for
corner cases that are broken in other areas of the kernel.
This patch (of 2):
Let's enforce pageblock_order < MAX_ORDER and simplify.
Especially patch #1 can be regarded a cleanup before:
[PATCH v5 0/6] Use pageblock_order for cma and alloc_contig_range
alignment. [2]
[1] https://lkml.kernel.org/r/87r189a2ks.fsf@linux.ibm.com
[2] https://lkml.kernel.org/r/20220211164135.1803616-1-zi.yan@sent.com
Link: https://lkml.kernel.org/r/20220214174132.219303-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Rob Herring <robh@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: John Garry via iommu <iommu@lists.linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/include/asm/fadump-internal.h | 5 | ||||
| -rw-r--r-- | arch/powerpc/kernel/fadump.c | 2 |
2 files changed, 1 insertions, 6 deletions
diff --git a/arch/powerpc/include/asm/fadump-internal.h b/arch/powerpc/include/asm/fadump-internal.h index 52189928ec08..81bcb9abb371 100644 --- a/arch/powerpc/include/asm/fadump-internal.h +++ b/arch/powerpc/include/asm/fadump-internal.h @@ -19,11 +19,6 @@ #define memblock_num_regions(memblock_type) (memblock.memblock_type.cnt) -/* Alignment per CMA requirement. */ -#define FADUMP_CMA_ALIGNMENT (PAGE_SIZE << \ - max_t(unsigned long, MAX_ORDER - 1, \ - pageblock_order)) - /* FAD commands */ #define FADUMP_REGISTER 1 #define FADUMP_UNREGISTER 2 diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index d03e488cfe9c..7eb67201ea41 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -544,7 +544,7 @@ int __init fadump_reserve_mem(void) if (!fw_dump.nocma) { fw_dump.boot_memory_size = ALIGN(fw_dump.boot_memory_size, - FADUMP_CMA_ALIGNMENT); + CMA_MIN_ALIGNMENT_BYTES); } #endif |