Don't set PROT_NONE for exclusive anonymas and maybe-dma-pinned pages for NUMA migration purpose. For exclusive anonymas and page_maybe_dma_pinned() pages, NUMA-migration will eventually drop migration of those pages in try_to_migrate_one(). (i.e. after -EBUSY returned in page_try_share_anon_rmap()). So, skip setting PROT_NONE to those kind of pages earlier in change_protection_range() phase to avoid later futile page faults, detections, and restoration to original PTEs/PMDs. Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx> --- mm/huge_memory.c | 5 +++++ mm/mprotect.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index eb3678360b97..a71cf686e3b2 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1875,6 +1875,11 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, goto unlock; page = pmd_page(*pmd); + + if (PageAnon(page) && PageAnonExclusive(page) && + page_maybe_dma_pinned(page)) + goto unlock; + toptier = node_is_toptier(page_to_nid(page)); /* * Skip scanning top tier node if normal numa diff --git a/mm/mprotect.c b/mm/mprotect.c index cb99a7d66467..a1f63df34b86 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -146,6 +146,11 @@ static long change_pte_range(struct mmu_gather *tlb, nid = page_to_nid(page); if (target_node == nid) continue; + + if (PageAnon(page) && PageAnonExclusive(page) && + page_maybe_dma_pinned(page)) + continue; + toptier = node_is_toptier(nid); /* -- 2.17.1
