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| author | Huang Ying <ying.huang@intel.com> | 2018-04-20 14:55:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-20 17:18:35 -0700 |
| commit | 88c28f2469151b031f8cea9b28ed5be1b74a4172 (patch) | |
| tree | 267a1a70a86b441e1a7131996c0447acb5b8198e | |
| parent | 8f175cf5c99dc0e3add2aac0ea1cd54e0f9ca87d (diff) | |
| download | linux-88c28f2469151b031f8cea9b28ed5be1b74a4172.tar.gz | |
mm, pagemap: fix swap offset value for PMD migration entry
The swap offset reported by /proc/<pid>/pagemap may be not correct for PMD migration entries. If addr passed into pagemap_pmd_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. This may happen after opening /proc/<pid>/pagemap and seeking to a page whose address doesn't align with a PMD start address. I have verified this with a simple test program. BTW: migration swap entries have PFN information, do we need to restrict whether to show them? [akpm@linux-foundation.org: fix typo, per Huang, Ying] Link: http://lkml.kernel.org/r/20180408033737.10897-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrei Vagin <avagin@openvz.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Jerome Glisse" <jglisse@redhat.com> Cc: Daniel Colascione <dancol@google.com> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/proc/task_mmu.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 65ae54659833..c486ad4b43f0 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; |