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H A D | radix_tlb.c | a42d6ba8 Thu Oct 24 02:57:59 CDT 2019 Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> powerpc/mm/book3s64/radix: Remove unused code.
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 commit 02390f66bd23 ("powerpc/64s/radix: Fix MADV_[FREE|DONTNEED] TLB flush miss problem with THP") and the problem is explained in detail in commit 99baac21e458 ("mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem")
This was later updated by commit 7a30df49f63a ("mm: mmu_gather: remove __tlb_reset_range() for force flush") to do a full mm flush rather than a range flush. By commit dd2283f2605e ("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 commit 02390f66bd23 ("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 a42d6ba8 Thu Oct 24 02:57:59 CDT 2019 Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> powerpc/mm/book3s64/radix: Remove unused code. 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 commit 02390f66bd23 ("powerpc/64s/radix: Fix MADV_[FREE|DONTNEED] TLB flush miss problem with THP") and the problem is explained in detail in commit 99baac21e458 ("mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem") This was later updated by commit 7a30df49f63a ("mm: mmu_gather: remove __tlb_reset_range() for force flush") to do a full mm flush rather than a range flush. By commit dd2283f2605e ("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 commit 02390f66bd23 ("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
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