Merge branch 'akpm' (Andrew's incoming - part two)

Says Andrew:

 "60 patches.  That's good enough for -rc1 I guess.  I have quite a lot
  of detritus to be rechecked, work through maintainers, etc.

 - most of the remains of MM
 - rtc
 - various misc
 - cgroups
 - memcg
 - cpusets
 - procfs
 - ipc
 - rapidio
 - sysctl
 - pps
 - w1
 - drivers/misc
 - aio"

* akpm: (60 commits)
  memcg: replace ss->id_lock with a rwlock
  aio: allocate kiocbs in batches
  drivers/misc/vmw_balloon.c: fix typo in code comment
  drivers/misc/vmw_balloon.c: determine page allocation flag can_sleep outside loop
  w1: disable irqs in critical section
  drivers/w1/w1_int.c: multiple masters used same init_name
  drivers/power/ds2780_battery.c: fix deadlock upon insertion and removal
  drivers/power/ds2780_battery.c: add a nolock function to w1 interface
  drivers/power/ds2780_battery.c: create central point for calling w1 interface
  w1: ds2760 and ds2780, use ida for id and ida_simple_get() to get it
  pps gpio client: add missing dependency
  pps: new client driver using GPIO
  pps: default echo function
  include/linux/dma-mapping.h: add dma_zalloc_coherent()
  sysctl: make CONFIG_SYSCTL_SYSCALL default to n
  sysctl: add support for poll()
  RapidIO: documentation update
  drivers/net/rionet.c: fix ethernet address macros for LE platforms
  RapidIO: fix potential null deref in rio_setup_device()
  RapidIO: add mport driver for Tsi721 bridge
  ...

1 files changed, 6 insertions, 3 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 10131fd..ed0ff44 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -949,6 +949,8 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
 static void cpuset_change_task_nodemask(struct task_struct *tsk,
 					nodemask_t *newmems)
 {
+	bool masks_disjoint = !nodes_intersects(*newmems, tsk->mems_allowed);
+
 repeat:
 	/*
 	 * Allow tasks that have access to memory reserves because they have
@@ -963,7 +965,6 @@ repeat:
 	nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
 	mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
 
-
 	/*
 	 * ensure checking ->mems_allowed_change_disable after setting all new
 	 * allowed nodes.
@@ -980,9 +981,11 @@ repeat:
 
 	/*
 	 * Allocation of memory is very fast, we needn't sleep when waiting
-	 * for the read-side.
+	 * for the read-side.  No wait is necessary, however, if at least one
+	 * node remains unchanged.
 	 */
-	while (ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
+	while (masks_disjoint &&
+			ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
 		task_unlock(tsk);
 		if (!task_curr(tsk))
 			yield();