Messages in this thread | | | Date | Fri, 6 Nov 2020 13:43:22 +0000 | From | Will Deacon <> | Subject | Re: [PATCH v4] arm64/mm: add fallback option to allocate virtually contiguous memory |
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On Fri, Oct 16, 2020 at 11:56:56AM -0700, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from > physically continuous memory of size PMD_SIZE using > vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB > pressure. But when system is highly fragmented and memory blocks are > being hot-added at runtime, its possible that such physically continuous > memory allocations can fail. Rather than failing the memory hot-add > procedure, add a fallback option to allocate vmemmap pages from > discontinuous pages using vmemmap_populate_basepages(). > > Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> > Reviewed-by: Gavin Shan <gshan@redhat.com> > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Logan Gunthorpe <logang@deltatee.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Steven Price <steven.price@arm.com> > --- > arch/arm64/mm/mmu.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 75df62fea1b6..44486fd0e883 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1121,8 +1121,11 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > void *p = NULL; > > p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); > - if (!p) > - return -ENOMEM; > + if (!p) { > + if (vmemmap_populate_basepages(addr, next, node, altmap)) > + return -ENOMEM; > + continue; > + }
Looks fine to me:
Acked-by: Will Deacon <will@kernel.org>
Will
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