1 files changed, 19 insertions, 34 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 8438c15..3416b6e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -125,17 +125,17 @@ core_initcall(init_zero_pfn);
 
 #if defined(SPLIT_RSS_COUNTING)
 
-static void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm)
+void sync_mm_rss(struct mm_struct *mm)
 {
 	int i;
 
 	for (i = 0; i < NR_MM_COUNTERS; i++) {
-		if (task->rss_stat.count[i]) {
-			add_mm_counter(mm, i, task->rss_stat.count[i]);
-			task->rss_stat.count[i] = 0;
+		if (current->rss_stat.count[i]) {
+			add_mm_counter(mm, i, current->rss_stat.count[i]);
+			current->rss_stat.count[i] = 0;
 		}
 	}
-	task->rss_stat.events = 0;
+	current->rss_stat.events = 0;
 }
 
 static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
@@ -157,30 +157,7 @@ static void check_sync_rss_stat(struct task_struct *task)
 	if (unlikely(task != current))
 		return;
 	if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
-		__sync_task_rss_stat(task, task->mm);
-}
-
-unsigned long get_mm_counter(struct mm_struct *mm, int member)
-{
-	long val = 0;
-
-	/*
-	 * Don't use task->mm here...for avoiding to use task_get_mm()..
-	 * The caller must guarantee task->mm is not invalid.
-	 */
-	val = atomic_long_read(&mm->rss_stat.count[member]);
-	/*
-	 * counter is updated in asynchronous manner and may go to minus.
-	 * But it's never be expected number for users.
-	 */
-	if (val < 0)
-		return 0;
-	return (unsigned long)val;
-}
-
-void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
-{
-	__sync_task_rss_stat(task, mm);
+		sync_mm_rss(task->mm);
 }
 #else /* SPLIT_RSS_COUNTING */
 
@@ -661,7 +638,7 @@ static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
 	int i;
 
 	if (current->mm == mm)
-		sync_mm_rss(current, mm);
+		sync_mm_rss(mm);
 	for (i = 0; i < NR_MM_COUNTERS; i++)
 		if (rss[i])
 			add_mm_counter(mm, i, rss[i]);
@@ -1247,16 +1224,24 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
 	do {
 		next = pmd_addr_end(addr, end);
 		if (pmd_trans_huge(*pmd)) {
-			if (next-addr != HPAGE_PMD_SIZE) {
+			if (next - addr != HPAGE_PMD_SIZE) {
 				VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem));
 				split_huge_page_pmd(vma->vm_mm, pmd);
 			} else if (zap_huge_pmd(tlb, vma, pmd, addr))
-				continue;
+				goto next;
 			/* fall through */
 		}
-		if (pmd_none_or_clear_bad(pmd))
-			continue;
+		/*
+		 * Here there can be other concurrent MADV_DONTNEED or
+		 * trans huge page faults running, and if the pmd is
+		 * none or trans huge it can change under us. This is
+		 * because MADV_DONTNEED holds the mmap_sem in read
+		 * mode.
+		 */
+		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
+			goto next;
 		next = zap_pte_range(tlb, vma, pmd, addr, next, details);
+next:
 		cond_resched();
 	} while (pmd++, addr = next, addr != end);