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Aneesh Kumar K.V
0b6f15824c
mm/vmemmap optimization: split hugetlb and devdax vmemmap optimization
Arm disabled hugetlb vmemmap optimization [1] because hugetlb vmemmap optimization includes an update of both the permissions (writeable to read-only) and the output address (pfn) of the vmemmap ptes. That is not supported without unmapping of pte(marking it invalid) by some architectures. With DAX vmemmap optimization we don't require such pte updates and architectures can enable DAX vmemmap optimization while having hugetlb vmemmap optimization disabled. Hence split DAX optimization support into a different config. s390, loongarch and riscv don't have devdax support. So the DAX config is not enabled for them. With this change, arm64 should be able to select DAX optimization [1] commit 060a2c92d1b6 ("arm64: mm: hugetlb: Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP") Link: https://lkml.kernel.org/r/20230724190759.483013-8-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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