memcg: flatten task_struct->memcg_oom

task_struct->memcg_oom is a sub-struct containing fields which are used
for async memcg oom handling.  Most task_struct fields aren't packaged
this way and it can lead to unnecessary alignment paddings.  This patch
flattens it.

* task.memcg_oom.memcg          -> task.memcg_in_oom
* task.memcg_oom.gfp_mask	-> task.memcg_oom_gfp_mask
* task.memcg_oom.order          -> task.memcg_oom_order
* task.memcg_oom.may_oom        -> task.memcg_may_oom

In addition, task.memcg_may_oom is relocated to where other bitfields are
which reduces the size of task_struct.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 7 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5423b9c82fee..17bf8b845aa0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1473,7 +1473,9 @@ struct task_struct {
         unsigned sched_reset_on_fork:1;
         unsigned sched_contributes_to_load:1;
         unsigned sched_migrated:1;
-
+#ifdef CONFIG_MEMCG
+        unsigned memcg_may_oom:1;
+#endif
 #ifdef CONFIG_MEMCG_KMEM
         unsigned memcg_kmem_skip_account:1;
 #endif
@@ -1804,12 +1806,9 @@ struct task_struct {
         unsigned long trace_recursion;
 #endif /* CONFIG_TRACING */
 #ifdef CONFIG_MEMCG
-        struct memcg_oom_info {
-                struct mem_cgroup *memcg;
-                gfp_t gfp_mask;
-                int order;
-                unsigned int may_oom:1;
-        } memcg_oom;
+        struct mem_cgroup *memcg_in_oom;
+        gfp_t memcg_oom_gfp_mask;
+        int memcg_oom_order;
 #endif
 #ifdef CONFIG_UPROBES
         struct uprobe_task *utask;