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authorBaolin Wang <baolin.wang@linux.alibaba.com>2022-05-09 18:20:52 -0700
committerAndrew Morton <akpm@linux-foundation.org>2022-05-13 07:20:07 -0700
commit3d0b95cd87b26b0b10e0cda8ee6105c2194a5800 (patch)
tree86532f8f27b7791c9157a1359a8707b2da7f320d /mm/mremap.c
parent6366238b8dfc383723c211c1ffe8c8d7914107e5 (diff)
mm: hugetlb: considering PMD sharing when flushing cache/TLBs
This patchset fixes some cache flushing issues if PMD sharing is possible for hugetlb pages, which were found by code inspection. Meanwhile Mike found the flush_cache_page() can not cover the whole size of a hugetlb page on some architectures [1], so I added a new patch 3 to fix this issue, since I found only try_to_unmap_one() and try_to_migrate_one() need to fix after some investigation. [1] https://lore.kernel.org/linux-mm/064da3bb-5b4b-7332-a722-c5a541128705@oracle.com/ This patch (of 3): When moving hugetlb page tables, the cache flushing is called in move_page_tables() without considering the shared PMDs, which may be cause cache issues on some architectures. Thus we should move the hugetlb cache flushing into move_hugetlb_page_tables() with considering the shared PMDs ranges, calculated by adjust_range_if_pmd_sharing_possible(). Meanwhile also expanding the TLBs flushing range in case of shared PMDs. Note this is discovered via code inspection, and did not meet a real problem in practice so far. Link: https://lkml.kernel.org/r/cover.1651056365.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/0443c8cf20db554d3ff4b439b30e0ff26c0181dd.1651056365.git.baolin.wang@linux.alibaba.com Fixes: 550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed vma") Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Mina Almasry <almasrymina@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mremap.c')
-rw-r--r--mm/mremap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index 98f50e633009..097002506d2d 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -490,12 +490,12 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
return 0;
old_end = old_addr + len;
- flush_cache_range(vma, old_addr, old_end);
if (is_vm_hugetlb_page(vma))
return move_hugetlb_page_tables(vma, new_vma, old_addr,
new_addr, len);
+ flush_cache_range(vma, old_addr, old_end);
mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm,
old_addr, old_end);
mmu_notifier_invalidate_range_start(&range);