Re: [PATCH v2] mm: proc: smaps_rollup: Fix pss_locked calculation

On Sat, Feb 02, 2019 at 10:54:25PM -0800, Sandeep Patil wrote:

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

---

Reviewed-by: Joel Fernandes (Google) joel@joelfernandes.org

thanks,

- Joel

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