mm: convert mm->nr_ptes to atomic_long_t

With split page table lock for PMD level we can't hold mm->page_table_lock
while updating nr_ptes.

Let's convert it to atomic_long_t to avoid races.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Alex Thorlton <athorlton@sgi.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 6738c47f1f72..1e4a600a6163 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -161,7 +161,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
          * The baseline for the badness score is the proportion of RAM that each
          * task's rss, pagetable and swap space use.
          */
-        points = get_mm_rss(p->mm) + p->mm->nr_ptes +
+        points = get_mm_rss(p->mm) + atomic_long_read(&p->mm->nr_ptes) +
                  get_mm_counter(p->mm, MM_SWAPENTS);
         task_unlock(p);
 
@@ -364,10 +364,10 @@ static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemas
                         continue;
                 }
 
-                pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu         %5hd %s\n",
+                pr_info("[%5d] %5d %5d %8lu %8lu %7ld %8lu         %5hd %s\n",
                         task->pid, from_kuid(&init_user_ns, task_uid(task)),
                         task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
-                        task->mm->nr_ptes,
+                        atomic_long_read(&task->mm->nr_ptes),
                         get_mm_counter(task->mm, MM_SWAPENTS),
                         task->signal->oom_score_adj, task->comm);
                 task_unlock(task);