From: David Howells on
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>

Commit 34e55232e59f7b19050267a05ff1226e5cd122a5 added sync_mm_rss() for
syncing loosely accounted rss counters. It's for CONFIG_MMU but sync_mm_rss
is called even in NOMMU enviroment (kerne/exit.c, fs/exec.c). Above commit
doesn't handle it well.

This patch changes
SPLIT_RSS_COUNTING depends on SPLIT_PTLOCKS && CONFIG_MMU

And for avoid unnecessary function calls, sync_mm_rss changed to be inlined
noop function in header file.

Reported-by: David Howells <dhowells(a)redhat.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>
Signed-off-by: Mike Frysinger <vapier(a)gentoo.org>
Signed-off-by: Michal Simek <monstr(a)monstr.eu>
Signed-off-by: David Howells <dhowells(a)redhat.com>
---

include/linux/mm.h | 6 ++++++
include/linux/mm_types.h | 2 +-
mm/memory.c | 3 ---
3 files changed, 7 insertions(+), 4 deletions(-)


diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3899395..7f693b2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -971,7 +971,13 @@ static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
*maxrss = hiwater_rss;
}

+#if defined(SPLIT_RSS_COUNTING)
void sync_mm_rss(struct task_struct *task, struct mm_struct *mm);
+#else
+static inline void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
+{
+}
+#endif

/*
* A callback you can register to apply pressure to ageable caches.
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 048b462..b8bb9a6 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -203,7 +203,7 @@ enum {
NR_MM_COUNTERS
};

-#if USE_SPLIT_PTLOCKS
+#if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
#define SPLIT_RSS_COUNTING
struct mm_rss_stat {
atomic_long_t count[NR_MM_COUNTERS];
diff --git a/mm/memory.c b/mm/memory.c
index d1153e3..3d9130b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -190,9 +190,6 @@ static void check_sync_rss_stat(struct task_struct *task)
{
}

-void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
-{
-}
#endif

/*

--
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