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>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 41c0a0a..98ba9ea 100644 (file)
--- 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;