mm, thp: remove infrastructure for handling splitting PMDs

With new refcounting we don't need to mark PMDs splitting.  Let's drop
code to handle this.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 11 deletions

diff --git a/mm/gup.c b/mm/gup.c
index 7017abe..70d65e4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -241,13 +241,6 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
 		spin_unlock(ptl);
 		return follow_page_pte(vma, address, pmd, flags);
 	}
-
-	if (unlikely(pmd_trans_splitting(*pmd))) {
-		spin_unlock(ptl);
-		wait_split_huge_page(vma->anon_vma, pmd);
-		return follow_page_pte(vma, address, pmd, flags);
-	}
-
 	if (flags & FOLL_SPLIT) {
 		int ret;
 		page = pmd_page(*pmd);
@@ -1068,9 +1061,6 @@ struct page *get_dump_page(unsigned long addr)
  *  *) HAVE_RCU_TABLE_FREE is enabled, and tlb_remove_table is used to free
  *      pages containing page tables.
  *
- *  *) THP splits will broadcast an IPI, this can be achieved by overriding
- *      pmdp_splitting_flush.
- *
  *  *) ptes can be read atomically by the architecture.
  *
  *  *) access_ok is sufficient to validate userspace address ranges.
@@ -1267,7 +1257,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
 		pmd_t pmd = READ_ONCE(*pmdp);
 
 		next = pmd_addr_end(addr, end);
-		if (pmd_none(pmd) || pmd_trans_splitting(pmd))
+		if (pmd_none(pmd))
 			return 0;
 
 		if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd))) {