The patch titled
Subject: thp: setup huge zero page on non-write page fault
has been added to the -mm tree. Its filename is
thp-setup-huge-zero-page-on-non-write-page-fault.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: thp: setup huge zero page on non-write page fault
All code paths seems covered. Now we can map huge zero page on read page
fault.
We setup it in do_huge_pmd_anonymous_page() if area around fault address
is suitable for THP and we've got read page fault.
If we fail to setup huge zero page (ENOMEM) we fallback to
handle_pte_fault() as we normally do in THP.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff -puN mm/huge_memory.c~thp-setup-huge-zero-page-on-non-write-page-fault mm/huge_memory.c
--- a/mm/huge_memory.c~thp-setup-huge-zero-page-on-non-write-page-fault
+++ a/mm/huge_memory.c
@@ -734,6 +734,16 @@ int do_huge_pmd_anonymous_page(struct mm
return VM_FAULT_OOM;
if (unlikely(khugepaged_enter(vma)))
return VM_FAULT_OOM;
+ if (!(flags & FAULT_FLAG_WRITE)) {
+ pgtable_t pgtable;
+ pgtable = pte_alloc_one(mm, haddr);
+ if (unlikely(!pgtable))
+ goto out;
+ spin_lock(&mm->page_table_lock);
+ set_huge_zero_page(pgtable, mm, vma, haddr, pmd);
+ spin_unlock(&mm->page_table_lock);
+ return 0;
+ }
page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
vma, haddr, numa_node_id(), 0);
if (unlikely(!page)) {
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
linux-next.patch
mm-use-is_enabledconfig_numa-instead-of-numa_build.patch
mm-use-is_enabledconfig_compaction-instead-of-compaction_build.patch
thp-huge-zero-page-basic-preparation.patch
thp-zap_huge_pmd-zap-huge-zero-pmd.patch
thp-copy_huge_pmd-copy-huge-zero-page.patch
thp-do_huge_pmd_wp_page-handle-huge-zero-page.patch
thp-change_huge_pmd-keep-huge-zero-page-write-protected.patch
thp-change-split_huge_page_pmd-interface.patch
thp-implement-splitting-pmd-for-huge-zero-page.patch
thp-setup-huge-zero-page-on-non-write-page-fault.patch
thp-lazy-huge-zero-page-allocation.patch
thp-implement-refcounting-for-huge-zero-page.patch
thp-vmstat-implement-hzp_alloc-and-hzp_alloc_failed-events.patch
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