mm: use updated pmdp_invalidate() interface to track dirty/accessed bits
Use the modifed pmdp_invalidate() that returns the previous value of pmd
to transfer dirty and accessed bits.
Link: http://lkml.kernel.org/r/20171213105756.69879-12-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Daney <david.daney@cavium.com>
Cc: David Miller <davem@davemloft.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Nitin Gupta <nitin.m.gupta@oracle.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 0d3ae51..2a79a6b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1910,17 +1910,7 @@
* pmdp_invalidate() is required to make sure we don't miss
* dirty/young flags set by hardware.
*/
- entry = *pmd;
- pmdp_invalidate(vma, addr, pmd);
-
- /*
- * Recover dirty/young flags. It relies on pmdp_invalidate to not
- * corrupt them.
- */
- if (pmd_dirty(*pmd))
- entry = pmd_mkdirty(entry);
- if (pmd_young(*pmd))
- entry = pmd_mkyoung(entry);
+ entry = pmdp_invalidate(vma, addr, pmd);
entry = pmd_modify(entry, newprot);
if (preserve_write)
@@ -2073,8 +2063,8 @@
struct mm_struct *mm = vma->vm_mm;
struct page *page;
pgtable_t pgtable;
- pmd_t _pmd;
- bool young, write, dirty, soft_dirty, pmd_migration = false;
+ pmd_t old, _pmd;
+ bool young, write, soft_dirty, pmd_migration = false;
unsigned long addr;
int i;
@@ -2130,7 +2120,6 @@
page_ref_add(page, HPAGE_PMD_NR - 1);
write = pmd_write(*pmd);
young = pmd_young(*pmd);
- dirty = pmd_dirty(*pmd);
soft_dirty = pmd_soft_dirty(*pmd);
pmdp_huge_split_prepare(vma, haddr, pmd);
@@ -2160,8 +2149,6 @@
if (soft_dirty)
entry = pte_mksoft_dirty(entry);
}
- if (dirty)
- SetPageDirty(page + i);
pte = pte_offset_map(&_pmd, addr);
BUG_ON(!pte_none(*pte));
set_pte_at(mm, addr, pte, entry);
@@ -2209,7 +2196,15 @@
* for this pmd), then we flush the SMP TLB and finally we write the
* non-huge version of the pmd entry with pmd_populate.
*/
- pmdp_invalidate(vma, haddr, pmd);
+ old = pmdp_invalidate(vma, haddr, pmd);
+
+ /*
+ * Transfer dirty bit using value returned by pmd_invalidate() to be
+ * sure we don't race with CPU that can set the bit under us.
+ */
+ if (pmd_dirty(old))
+ SetPageDirty(page);
+
pmd_populate(mm, pmd, pgtable);
if (freeze) {