Messages in this thread | | | Subject | Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory | From | Gavin Shan <> | Date | Mon, 12 Oct 2020 13:54:40 +1100 |
| |
On 10/6/20 2:36 PM, Anshuman Khandual wrote: > On 10/02/2020 01:46 AM, 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> >> 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 | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >>
It looks good to me with Anshuman's comments fixed:
Reviewed-by: Gavin Shan <gshan@redhat.com>
>> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index 75df62f..11f8639 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1121,8 +1121,15 @@ 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) { >> + /* >> + * fallback allocating with virtually >> + * contiguous memory for this section >> + */ > > Mapping is always virtually contiguous with or without huge pages. > Please drop this comment here, as it's obvious. > >> + if (vmemmap_populate_basepages(addr, next, node, NULL)) >> + return -ENOMEM; > > Please send in the 'altmap' instead of NULL for allocation from > device memory if and when requested. > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
| |