mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range

We remove one instace of flush_tlb_range here.  That was added by commit
f714f4f2 ("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>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/pgtable.h

@@ -783,6 +783,23 @@ static inline int pmd_clear_huge(pmd_t *pmd)
 }
 #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
+#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * ARCHes with special requirements for evicting THP backing TLB entries can
+ * implement this. Otherwise also, it can help optimize normal TLB flush in
+ * THP regime. stock flush_tlb_range() typically has optimization to nuke the
+ * entire TLB TLB if flush span is greater than a threshold, which will
+ * likely be true for a single huge page. Thus a single thp flush will
+ * invalidate the entire TLB which is not desitable.
+ * e.g. see arch/arc: flush_pmd_tlb_range
+ */
+#define flush_pmd_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
+#else
+#define flush_pmd_tlb_range(vma, addr, end)	BUILD_BUG()
+#endif
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #ifndef io_remap_pfn_range

mm/migrate.c

@@ -1773,7 +1773,10 @@ 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);
 
@@ -1829,12 +1832,11 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 	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);

mm/pgtable-generic.c

@@ -84,20 +84,6 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 
-#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
-
-/*
- * ARCHes with special requirements for evicting THP backing TLB entries can
- * implement this. Otherwise also, it can help optimize normal TLB flush in
- * THP regime. stock flush_tlb_range() typically has optimization to nuke the
- * entire TLB if flush span is greater than a threshold, which will
- * likely be true for a single huge page. Thus a single thp flush will
- * invalidate the entire TLB which is not desirable.
- * e.g. see arch/arc: flush_pmd_tlb_range
- */
-#define flush_pmd_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
-#endif
-
 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 int pmdp_set_access_flags(struct vm_area_struct *vma,
 			  unsigned long address, pmd_t *pmdp,