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mm_tlb_flush_nested change was added in the mmu gather tlb flush to handle the case of parallel pte invalidate happening with mmap_sem held in read mode. This fix was done by commit02390f66bd("powerpc/64s/radix: Fix MADV_[FREE|DONTNEED] TLB flush miss problem with THP") and the problem is explained in detail in commit99baac21e4("mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem") This was later updated by commit7a30df49f6("mm: mmu_gather: remove __tlb_reset_range() for force flush") to do a full mm flush rather than a range flush. By commitdd2283f260("mm: mmap: zap pages with read mmap_sem in munmap") we are also now allowing a page table free in mmap_sem read mode which means we should do a PWC flush too. Our current full mm flush imply a PWC flush. With all the above change the mm_tlb_flush_nested(mm) branch in radix__tlb_flush will never be taken because for the nested case we would have taken the if (tlb->fullmm) branch. This patch removes the unused code. Also, remove the gflush change in __radix__flush_tlb_range that was added to handle the range tlb flush code. We only check for THP there because hugetlb is flushed via a different code path where page size is explicitly specified. This is a partial revert of commit02390f66bd("powerpc/64s/radix: Fix MADV_[FREE|DONTNEED] TLB flush miss problem with THP") Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191024075801.22434-1-aneesh.kumar@linux.ibm.com
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.