From: Huang Ying ying.huang@intel.com
mainline inclusion from mainline-v5.15-rc1 commit f00230ff8411eaecbea1f2e528e205424f3725ba category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAFONL CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Before commit c5b5a3dd2c1f ("mm: thp: refactor NUMA fault handling"), the TLB flushing is done in do_huge_pmd_numa_page() itself via flush_tlb_range().
But after commit c5b5a3dd2c1f ("mm: thp: refactor NUMA fault handling"), the TLB flushing is done in migrate_pages() as in the following code path anyway.
do_huge_pmd_numa_page migrate_misplaced_page migrate_pages
So now, the TLB flushing code in do_huge_pmd_numa_page() becomes unnecessary. So the code is deleted in this patch to simplify the code. This is only code cleanup, there's no visible performance difference.
The mmu_notifier_invalidate_range() in do_huge_pmd_numa_page() is deleted too. Because migrate_pages() takes care of that too when CPU TLB is flushed.
Link: https://lkml.kernel.org/r/20210720065529.716031-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" ying.huang@intel.com Reviewed-by: Zi Yan ziy@nvidia.com Reviewed-by: Yang Shi shy828301@gmail.com Cc: Dan Carpenter dan.carpenter@oracle.com Cc: Mel Gorman mgorman@suse.de Cc: Christian Borntraeger borntraeger@de.ibm.com Cc: Gerald Schaefer gerald.schaefer@linux.ibm.com Cc: Heiko Carstens hca@linux.ibm.com Cc: Hugh Dickins hughd@google.com Cc: Andrea Arcangeli aarcange@redhat.com Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Michal Hocko mhocko@suse.com Cc: Vasily Gorbik gor@linux.ibm.com Cc: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Nanyong Sun sunnanyong@huawei.com --- mm/huge_memory.c | 26 -------------------------- 1 file changed, 26 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 72b4f10b822f..eb293d17a104 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1444,32 +1444,6 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) goto out; }
- /* - * Since we took the NUMA fault, we must have observed the !accessible - * bit. Make sure all other CPUs agree with that, to avoid them - * modifying the page we're about to migrate. - * - * Must be done under PTL such that we'll observe the relevant - * inc_tlb_flush_pending(). - * - * We are not sure a pending tlb flush here is for a huge page - * mapping or not. Hence use the tlb range variant - */ - if (mm_tlb_flush_pending(vma->vm_mm)) { - flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); - /* - * change_huge_pmd() released the pmd lock before - * invalidating the secondary MMUs sharing the primary - * MMU pagetables (with ->invalidate_range()). The - * mmu_notifier_invalidate_range_end() (which - * internally calls ->invalidate_range()) in - * change_pmd_range() will run after us, so we can't - * rely on it here and we need an explicit invalidate. - */ - mmu_notifier_invalidate_range(vma->vm_mm, haddr, - haddr + HPAGE_PMD_SIZE); - } - pmd = pmd_modify(oldpmd, vma->vm_page_prot); page = vm_normal_page_pmd(vma, haddr, pmd); if (!page)