Messages in this thread Patch in this message |  | | Subject | Re: [PATCH] /proc/PID/smaps: Add PMD migration entry parsing | From | Konstantin Khlebnikov <> | Date | Tue, 31 Mar 2020 12:51:38 +0300 |
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On 31/03/2020 11.56, Huang, Ying wrote: > From: Huang Ying <ying.huang@intel.com> > > Now, when read /proc/PID/smaps, the PMD migration entry in page table is simply > ignored. To improve the accuracy of /proc/PID/smaps, its parsing and processing > is added. > > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > Cc: Andrea Arcangeli <aarcange@redhat.com> > Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Cc: Zi Yan <ziy@nvidia.com> > Cc: Vlastimil Babka <vbabka@suse.cz> > Cc: Alexey Dobriyan <adobriyan@gmail.com> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> > Cc: "Jérôme Glisse" <jglisse@redhat.com> > Cc: Yang Shi <yang.shi@linux.alibaba.com> > --- > fs/proc/task_mmu.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 8d382d4ec067..b5b3aef8cb3b 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -548,8 +548,17 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, > bool locked = !!(vma->vm_flags & VM_LOCKED); > struct page *page;
struct page *page = NULL;
> > - /* FOLL_DUMP will return -EFAULT on huge zero page */ > - page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); > + if (pmd_present(*pmd)) { > + /* FOLL_DUMP will return -EFAULT on huge zero page */ > + page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); > + } else if (unlikely(is_swap_pmd(*pmd))) { > + swp_entry_t entry = pmd_to_swp_entry(*pmd); > + > + VM_BUG_ON(!is_migration_entry(entry)); > + page = migration_entry_to_page(entry);
if (is_migration_entry(entry)) page = migration_entry_to_page(entry);
Seems safer and doesn't add much code.
> + } else { > + return; > + } > if (IS_ERR_OR_NULL(page)) > return; > if (PageAnon(page)) > @@ -578,8 +587,7 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, > > ptl = pmd_trans_huge_lock(pmd, vma); > if (ptl) { > - if (pmd_present(*pmd)) > - smaps_pmd_entry(pmd, addr, walk); > + smaps_pmd_entry(pmd, addr, walk); > spin_unlock(ptl); > goto out; > } >
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