vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces

The VM accounting makes no sense at this level, and half of the callers
didn't ever actually use the end result.  The only time we want to
unaccount the memory is when we actually remove the vma, so do the
accounting at that point instead.

This simplifies the interfaces (no need to pass down that silly page
counter to functions that really don't care), and also makes it much
more obvious what is actually going on: we do vm_[un]acct_memory() when
adding or removing the vma, not on random page walking.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 11 deletions

diff --git a/mm/memory.c b/mm/memory.c
index f7b6c98..1e77da6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1295,7 +1295,7 @@ static void unmap_page_range(struct mmu_gather *tlb,
 
 static void unmap_single_vma(struct mmu_gather *tlb,
 		struct vm_area_struct *vma, unsigned long start_addr,
-		unsigned long end_addr, unsigned long *nr_accounted,
+		unsigned long end_addr,
 		struct zap_details *details)
 {
 	unsigned long start = max(vma->vm_start, start_addr);
@@ -1307,9 +1307,6 @@ static void unmap_single_vma(struct mmu_gather *tlb,
 	if (end <= vma->vm_start)
 		return;
 
-	if (vma->vm_flags & VM_ACCOUNT)
-		*nr_accounted += (end - start) >> PAGE_SHIFT;
-
 	if (unlikely(is_pfn_mapping(vma)))
 		untrack_pfn_vma(vma, 0, 0);
 
@@ -1339,7 +1336,6 @@ static void unmap_single_vma(struct mmu_gather *tlb,
  * @vma: the starting vma
  * @start_addr: virtual address at which to start unmapping
  * @end_addr: virtual address at which to end unmapping
- * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
  *
  * Unmap all pages in the vma list.
  *
@@ -1354,13 +1350,13 @@ static void unmap_single_vma(struct mmu_gather *tlb,
  */
 void unmap_vmas(struct mmu_gather *tlb,
 		struct vm_area_struct *vma, unsigned long start_addr,
-		unsigned long end_addr, unsigned long *nr_accounted)
+		unsigned long end_addr)
 {
 	struct mm_struct *mm = vma->vm_mm;
 
 	mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
 	for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
-		unmap_single_vma(tlb, vma, start_addr, end_addr, nr_accounted, NULL);
+		unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
 	mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
 }
 
@@ -1379,14 +1375,13 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start,
 	struct mm_struct *mm = vma->vm_mm;
 	struct mmu_gather tlb;
 	unsigned long end = start + size;
-	unsigned long nr_accounted = 0;
 
 	lru_add_drain();
 	tlb_gather_mmu(&tlb, mm, 0);
 	update_hiwater_rss(mm);
 	mmu_notifier_invalidate_range_start(mm, start, end);
 	for ( ; vma && vma->vm_start < end; vma = vma->vm_next)
-		unmap_single_vma(&tlb, vma, start, end, &nr_accounted, details);
+		unmap_single_vma(&tlb, vma, start, end, details);
 	mmu_notifier_invalidate_range_end(mm, start, end);
 	tlb_finish_mmu(&tlb, start, end);
 }
@@ -1406,13 +1401,12 @@ static void zap_page_range_single(struct vm_area_struct *vma, unsigned long addr
 	struct mm_struct *mm = vma->vm_mm;
 	struct mmu_gather tlb;
 	unsigned long end = address + size;
-	unsigned long nr_accounted = 0;
 
 	lru_add_drain();
 	tlb_gather_mmu(&tlb, mm, 0);
 	update_hiwater_rss(mm);
 	mmu_notifier_invalidate_range_start(mm, address, end);
-	unmap_single_vma(&tlb, vma, address, end, &nr_accounted, details);
+	unmap_single_vma(&tlb, vma, address, end, details);
 	mmu_notifier_invalidate_range_end(mm, address, end);
 	tlb_finish_mmu(&tlb, address, end);
 }