pagemap: rework hugetlb and thp report

This patch moves pmd dissection out of reporting loop: huge pages are
reported as bunch of normal pages with contiguous PFNs.

Add missing "FILE" bit in hugetlb vmas.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Mark Williamson <mwilliamson@undo-software.com>
Tested-by:  Mark Williamson <mwilliamson@undo-software.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 44 insertions, 56 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 41c0a0a500f7..98ba9ea96b19 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1040,33 +1040,7 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
         return make_pme(frame, flags);
 }
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm,
-                pmd_t pmd, int offset, u64 flags)
-{
-        u64 frame = 0;
-
-        /*
-         * Currently pmd for thp is always present because thp can not be
-         * swapped-out, migrated, or HWPOISONed (split in such cases instead.)
-         * This if-check is just to prepare for future implementation.
-         */
-        if (pmd_present(pmd)) {
-                frame = pmd_pfn(pmd) + offset;
-                flags |= PM_PRESENT;
-        }
-
-        return make_pme(frame, flags);
-}
-#else
-static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm,
-                pmd_t pmd, int offset, u64 flags)
-{
-        return make_pme(0, 0);
-}
-#endif
-
-static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
                              struct mm_walk *walk)
 {
         struct vm_area_struct *vma = walk->vma;
@@ -1075,35 +1049,48 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
         pte_t *pte, *orig_pte;
         int err = 0;
 
-        if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
-                u64 flags = 0;
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        if (pmd_trans_huge_lock(pmdp, vma, &ptl) == 1) {
+                u64 flags = 0, frame = 0;
+                pmd_t pmd = *pmdp;
 
-                if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
+                if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(pmd))
                         flags |= PM_SOFT_DIRTY;
 
+                /*
+                 * Currently pmd for thp is always present because thp
+                 * can not be swapped-out, migrated, or HWPOISONed
+                 * (split in such cases instead.)
+                 * This if-check is just to prepare for future implementation.
+                 */
+                if (pmd_present(pmd)) {
+                        flags |= PM_PRESENT;
+                        frame = pmd_pfn(pmd) +
+                                ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+                }
+
                 for (; addr != end; addr += PAGE_SIZE) {
-                        unsigned long offset;
-                        pagemap_entry_t pme;
+                        pagemap_entry_t pme = make_pme(frame, flags);
 
-                        offset = (addr & ~PAGEMAP_WALK_MASK) >>
-                                        PAGE_SHIFT;
-                        pme = thp_pmd_to_pagemap_entry(pm, *pmd, offset, flags);
                         err = add_to_pagemap(addr, &pme, pm);
                         if (err)
                                 break;
+                        if (flags & PM_PRESENT)
+                                frame++;
                 }
                 spin_unlock(ptl);
                 return err;
         }
 
-        if (pmd_trans_unstable(pmd))
+        if (pmd_trans_unstable(pmdp))
                 return 0;
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
         /*
          * We can assume that @vma always points to a valid one and @end never
          * goes beyond vma->vm_end.
          */
-        orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+        orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
         for (; addr < end; pte++, addr += PAGE_SIZE) {
                 pagemap_entry_t pme;
 
@@ -1120,39 +1107,40 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 }
 
 #ifdef CONFIG_HUGETLB_PAGE
-static pagemap_entry_t huge_pte_to_pagemap_entry(struct pagemapread *pm,
-                                        pte_t pte, int offset, u64 flags)
-{
-        u64 frame = 0;
-
-        if (pte_present(pte)) {
-                frame = pte_pfn(pte) + offset;
-                flags |= PM_PRESENT;
-        }
-
-        return make_pme(frame, flags);
-}
-
 /* This function walks within one hugetlb entry in the single call */
-static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
+static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
                                  unsigned long addr, unsigned long end,
                                  struct mm_walk *walk)
 {
         struct pagemapread *pm = walk->private;
         struct vm_area_struct *vma = walk->vma;
+        u64 flags = 0, frame = 0;
         int err = 0;
-        u64 flags = 0;
-        pagemap_entry_t pme;
+        pte_t pte;
 
         if (vma->vm_flags & VM_SOFTDIRTY)
                 flags |= PM_SOFT_DIRTY;
 
+        pte = huge_ptep_get(ptep);
+        if (pte_present(pte)) {
+                struct page *page = pte_page(pte);
+
+                if (!PageAnon(page))
+                        flags |= PM_FILE;
+
+                flags |= PM_PRESENT;
+                frame = pte_pfn(pte) +
+                        ((addr & ~hmask) >> PAGE_SHIFT);
+        }
+
         for (; addr != end; addr += PAGE_SIZE) {
-                int offset = (addr & ~hmask) >> PAGE_SHIFT;
-                pme = huge_pte_to_pagemap_entry(pm, *pte, offset, flags);
+                pagemap_entry_t pme = make_pme(frame, flags);
+
                 err = add_to_pagemap(addr, &pme, pm);
                 if (err)
                         return err;
+                if (flags & PM_PRESENT)
+                        frame++;
         }
 
         cond_resched();
@@ -1216,7 +1204,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
         if (!pm.buffer)
                 goto out_mm;
 
-        pagemap_walk.pmd_entry = pagemap_pte_range;
+        pagemap_walk.pmd_entry = pagemap_pmd_range;
         pagemap_walk.pte_hole = pagemap_pte_hole;
 #ifdef CONFIG_HUGETLB_PAGE
         pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;