[PATCH] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range

[PATCH] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range

[Aneesh Kumar K.V]

We remove one instace of flush_tlb_range here. That was added by
f714f4f20e59ea6eea264a86b9a51fd51b88fc54 ("mm: numa: call MMU notifiers
on THP migration"). But the pmdp_huge_clear_flush_notify should have
done the require flush for us. Hence remove the extra flush.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 mm/migrate.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index b1034f9c77e7..c079c115d038 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1767,7 +1767,10 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 		put_page(new_page);
 		goto out_fail;
 	}
-
+	/*
+	 * We are not sure a pending tlb flush here is for a huge page
+	 * mapping or not. Hence use the tlb range variant
+	 */
 	if (mm_tlb_flush_pending(mm))
 		flush_tlb_range(vma, mmun_start, mmun_end);
 
@@ -1823,12 +1826,11 @@ fail_putback:
 	page_add_anon_rmap(new_page, vma, mmun_start, true);
 	pmdp_huge_clear_flush_notify(vma, mmun_start, pmd);
 	set_pmd_at(mm, mmun_start, pmd, entry);
-	flush_tlb_range(vma, mmun_start, mmun_end);
 	update_mmu_cache_pmd(vma, address, &entry);
 
 	if (page_count(page) != 2) {
 		set_pmd_at(mm, mmun_start, pmd, orig_entry);
-		flush_tlb_range(vma, mmun_start, mmun_end);
+		flush_pmd_tlb_range(vma, mmun_start, mmun_end);
 		mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
 		update_mmu_cache_pmd(vma, address, &entry);
 		page_remove_rmap(new_page, true);
-- 
2.5.0

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Re: [PATCH] mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range

[kbuild test robot]

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Hi Aneesh,

[auto build test ERROR on v4.5-rc3]
[also build test ERROR on next-20160209]
[cannot apply to arc/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Aneesh-Kumar-K-V/mm-thp-migration-switch-from-flush_tlb_range-to-flush_pmd_tlb_range/20160210-135701
config: x86_64-randconfig-x012-201606 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   mm/migrate.c: In function 'migrate_misplaced_transhuge_page':
>> mm/migrate.c:1833:3: error: implicit declaration of function 'flush_pmd_tlb_range' [-Werror=implicit-function-declaration]
      flush_pmd_tlb_range(vma, mmun_start, mmun_end);
      ^
   cc1: some warnings being treated as errors

vim +/flush_pmd_tlb_range +1833 mm/migrate.c

  1827		pmdp_huge_clear_flush_notify(vma, mmun_start, pmd);
  1828		set_pmd_at(mm, mmun_start, pmd, entry);
  1829		update_mmu_cache_pmd(vma, address, &entry);
  1830	
  1831		if (page_count(page) != 2) {
  1832			set_pmd_at(mm, mmun_start, pmd, orig_entry);
> 1833			flush_pmd_tlb_range(vma, mmun_start, mmun_end);
  1834			mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
  1835			update_mmu_cache_pmd(vma, address, &entry);
  1836			page_remove_rmap(new_page, true);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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