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Subject[PATCH v2] mm: proc: smaps_rollup: Fix pss_locked calculation
Date
The 'pss_locked' field of smaps_rollup was being calculated incorrectly.
It accumulated the current pss everytime a locked VMA was found. Fix
that by adding to 'pss_locked' the same time as that of 'pss' if the vma
being walked is locked.

Fixes: 493b0e9d945f ("mm: add /proc/pid/smaps_rollup")
Cc: stable@vger.kernel.org # 4.14.y 4.19.y
Signed-off-by: Sandeep Patil <sspatil@android.com>
---

v1->v2
------
- Move pss_locked accounting into smaps_account() inline with pss

fs/proc/task_mmu.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index f0ec9edab2f3..85b0ef890b28 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -423,7 +423,7 @@ struct mem_size_stats {
};

static void smaps_account(struct mem_size_stats *mss, struct page *page,
- bool compound, bool young, bool dirty)
+ bool compound, bool young, bool dirty, bool locked)
{
int i, nr = compound ? 1 << compound_order(page) : 1;
unsigned long size = nr * PAGE_SIZE;
@@ -450,24 +450,31 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
else
mss->private_clean += size;
mss->pss += (u64)size << PSS_SHIFT;
+ if (locked)
+ mss->pss_locked += (u64)size << PSS_SHIFT;
return;
}

for (i = 0; i < nr; i++, page++) {
int mapcount = page_mapcount(page);
+ unsigned long pss = (PAGE_SIZE << PSS_SHIFT);

if (mapcount >= 2) {
if (dirty || PageDirty(page))
mss->shared_dirty += PAGE_SIZE;
else
mss->shared_clean += PAGE_SIZE;
- mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount;
+ mss->pss += pss / mapcount;
+ if (locked)
+ mss->pss_locked += pss / mapcount;
} else {
if (dirty || PageDirty(page))
mss->private_dirty += PAGE_SIZE;
else
mss->private_clean += PAGE_SIZE;
- mss->pss += PAGE_SIZE << PSS_SHIFT;
+ mss->pss += pss;
+ if (locked)
+ mss->pss_locked += pss;
}
}
}
@@ -490,6 +497,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = walk->vma;
+ bool locked = !!(vma->vm_flags & VM_LOCKED);
struct page *page = NULL;

if (pte_present(*pte)) {
@@ -532,7 +540,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
if (!page)
return;

- smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte));
+ smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte), locked);
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -541,6 +549,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = walk->vma;
+ bool locked = !!(vma->vm_flags & VM_LOCKED);
struct page *page;

/* FOLL_DUMP will return -EFAULT on huge zero page */
@@ -555,7 +564,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
/* pass */;
else
VM_BUG_ON_PAGE(1, page);
- smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd));
+ smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd), locked);
}
#else
static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
@@ -737,11 +746,8 @@ static void smap_gather_stats(struct vm_area_struct *vma,
}
}
#endif
-
/* mmap_sem is held in m_start */
walk_page_vma(vma, &smaps_walk);
- if (vma->vm_flags & VM_LOCKED)
- mss->pss_locked += mss->pss;
}

#define SEQ_PUT_DEC(str, val) \
--
2.20.1.611.gfbb209baf1-goog
\
 
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