From: Huang Ying <ying.huang@xxxxxxxxx>
The swap offset reported by /proc/<pid>/pagemap may be not correct for
PMD migration entry. If addr passed into pagemap_range() isn't
aligned with PMD start address, the swap offset reported doesn't
reflect this. And in the loop to report information of each sub-page,
the swap offset isn't increased accordingly as that for PFN.
BTW: migration swap entries have PFN information, do we need to
restrict whether to show them?
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrei Vagin <avagin@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: "Jerome Glisse" <jglisse@xxxxxxxxxx>
Cc: Daniel Colascione <dancol@xxxxxxxxxx>
Cc: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 65ae54659833..757e748da613 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1310,9 +1310,11 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
else if (is_swap_pmd(pmd)) {
swp_entry_t entry = pmd_to_swp_entry(pmd);
+ unsigned long offset = swp_offset(entry);
+ offset += (addr & ~PMD_MASK) >> PAGE_SHIFT;
frame = swp_type(entry) |
- (swp_offset(entry) << MAX_SWAPFILES_SHIFT);
+ (offset << MAX_SWAPFILES_SHIFT);
flags |= PM_SWAP;
if (pmd_swp_soft_dirty(pmd))
flags |= PM_SOFT_DIRTY;
@@ -1332,6 +1334,8 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
break;
if (pm->show_pfn && (flags & PM_PRESENT))
frame++;
+ else if (flags | PM_SWAP)
+ frame += (1 << MAX_SWAPFILES_SHIFT);
}
spin_unlock(ptl);
return err;
--
2.15.1
