[RFC PATCH 2/7] mm: move check_mm to memory.c

[Kairui Song <ryncsn@gmail.com>]

From: Kairui Song <kasong@tencent.com>

No function change, make it possible to do extra mm operation on mm exit,
prepare for following commits.

Signed-off-by: Kairui Song <kasong@tencent.com>
---
 include/linux/mm.h |  3 +++
 kernel/fork.c      | 33 ---------------------------------
 mm/memory.c        | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6346f7e77dc7..81ad91621078 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1993,6 +1993,9 @@ static inline bool get_user_page_fast_only(unsigned long addr,
 {
 	return get_user_pages_fast_only(addr, 1, gup_flags, pagep) == 1;
 }
+
+void check_mm(struct mm_struct *mm);
+
 /*
  * per-process(per-mm_struct) statistics.
  */
diff --git a/kernel/fork.c b/kernel/fork.c
index c090ebd55063..86a239772208 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -128,15 +128,6 @@ int nr_threads;			/* The idle threads do not count.. */
 
 static int max_threads;		/* tunable limit on nr_threads */
 
-#define NAMED_ARRAY_INDEX(x)	[x] = __stringify(x)
-
-static const char * const resident_page_types[] = {
-	NAMED_ARRAY_INDEX(MM_FILEPAGES),
-	NAMED_ARRAY_INDEX(MM_ANONPAGES),
-	NAMED_ARRAY_INDEX(MM_SWAPENTS),
-	NAMED_ARRAY_INDEX(MM_SHMEMPAGES),
-};
-
 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
 
 __cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */
@@ -748,30 +739,6 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 #define mm_free_pgd(mm)
 #endif /* CONFIG_MMU */
 
-static void check_mm(struct mm_struct *mm)
-{
-	int i;
-
-	BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS,
-			 "Please make sure 'struct resident_page_types[]' is updated as well");
-
-	for (i = 0; i < NR_MM_COUNTERS; i++) {
-		long x = atomic_long_read(&mm->rss_stat.count[i]);
-
-		if (unlikely(x))
-			pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
-				 mm, resident_page_types[i], x);
-	}
-
-	if (mm_pgtables_bytes(mm))
-		pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
-				mm_pgtables_bytes(mm));
-
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
-	VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
-#endif
-}
-
 #define allocate_mm()	(kmem_cache_alloc(mm_cachep, GFP_KERNEL))
 #define free_mm(mm)	(kmem_cache_free(mm_cachep, (mm)))
 
diff --git a/mm/memory.c b/mm/memory.c
index 6bf7826e666b..c0597214f9b3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -179,6 +179,38 @@ void mm_trace_rss_stat(struct mm_struct *mm, int member, long count)
 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
 
+#define NAMED_ARRAY_INDEX(x)	[x] = __stringify(x)
+static const char * const resident_page_types[] = {
+	NAMED_ARRAY_INDEX(MM_FILEPAGES),
+	NAMED_ARRAY_INDEX(MM_ANONPAGES),
+	NAMED_ARRAY_INDEX(MM_SWAPENTS),
+	NAMED_ARRAY_INDEX(MM_SHMEMPAGES),
+};
+
+void check_mm(struct mm_struct *mm)
+{
+	int i;
+
+	BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS,
+			 "Please make sure 'struct resident_page_types[]' is updated as well");
+
+	for (i = 0; i < NR_MM_COUNTERS; i++) {
+		long x = atomic_long_read(&mm->rss_stat.count[i]);
+
+		if (unlikely(x))
+			pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
+				 mm, resident_page_types[i], x);
+	}
+
+	if (mm_pgtables_bytes(mm))
+		pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
+				mm_pgtables_bytes(mm));
+
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
+	VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
+#endif
+}
+
 /*
  * Note: this doesn't free the actual pages themselves. That
  * has been handled earlier when unmapping all the memory regions.
-- 
2.35.2