diff options
| author | Huang Ying <ying.huang@intel.com> | 2020-06-01 21:50:05 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-02 10:59:10 -0700 |
| commit | c94b6923fa0a954fbe14ea0168b9d324011fd817 (patch) | |
| tree | 413eeb55b72eb140fc22caee996ca897bea5bc7a /fs/proc | |
| parent | 99395ee3f7b4accc3a16a6aa4c2abb3774fc33ca (diff) | |
/proc/PID/smaps: Add PMD migration entry parsing
Now, when reading /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.
To test the patch, we run pmbench to eat 400 MB memory in background,
then run /usr/bin/migratepages and `cat /proc/PID/smaps` every second.
The issue as follows can be reproduced within 60 seconds.
Before the patch, for the fully populated 400 MB anonymous VMA, some THP
pages under migration may be lost as below.
7f3f6a7e5000-7f3f837e5000 rw-p 00000000 00:00 0
Size: 409600 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Rss: 407552 kB
Pss: 407552 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 407552 kB
Referenced: 301056 kB
Anonymous: 407552 kB
LazyFree: 0 kB
AnonHugePages: 405504 kB
ShmemPmdMapped: 0 kB
FilePmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
Locked: 0 kB
THPeligible: 1
VmFlags: rd wr mr mw me ac
After the patch, it will be always,
7f3f6a7e5000-7f3f837e5000 rw-p 00000000 00:00 0
Size: 409600 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Rss: 409600 kB
Pss: 409600 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 409600 kB
Referenced: 294912 kB
Anonymous: 409600 kB
LazyFree: 0 kB
AnonHugePages: 407552 kB
ShmemPmdMapped: 0 kB
FilePmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
Locked: 0 kB
THPeligible: 1
VmFlags: rd wr mr mw me ac
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Link: http://lkml.kernel.org/r/20200403123059.1846960-1-ying.huang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/task_mmu.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 8d382d4ec067..36dc7417c0df 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -546,10 +546,17 @@ 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; + struct page *page = NULL; + + 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(thp_migration_supported() && is_swap_pmd(*pmd))) { + swp_entry_t entry = pmd_to_swp_entry(*pmd); - /* FOLL_DUMP will return -EFAULT on huge zero page */ - page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); + if (is_migration_entry(entry)) + page = migration_entry_to_page(entry); + } if (IS_ERR_OR_NULL(page)) return; if (PageAnon(page)) @@ -578,8 +585,7 @@ 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; } |