ovl: Fix ovl_getattr() to get number of blocks from lower

[linux.git] / mm / backing-dev.c

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 7441bd93b732000f7405f191991b102eefc26832..347cc834c04a8cbc388af1b7594e4f09bdc68b41 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -412,6 +412,7 @@ static void wb_exit(struct bdi_writeback *wb)
  * protected.
  */
 static DEFINE_SPINLOCK(cgwb_lock);
+static struct workqueue_struct *cgwb_release_wq;
 
 /**
  * wb_congested_get_create - get or create a wb_congested
@@ -522,7 +523,7 @@ static void cgwb_release(struct percpu_ref *refcnt)
 {
        struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback,
                                                refcnt);
-       schedule_work(&wb->release_work);
+       queue_work(cgwb_release_wq, &wb->release_work);
 }
 
 static void cgwb_kill(struct bdi_writeback *wb)
@@ -556,7 +557,7 @@ static int cgwb_create(struct backing_dev_info *bdi,
        memcg = mem_cgroup_from_css(memcg_css);
        blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys);
        blkcg = css_to_blkcg(blkcg_css);
-       memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
+       memcg_cgwb_list = &memcg->cgwb_list;
        blkcg_cgwb_list = &blkcg->cgwb_list;
 
        /* look up again under lock and discard on blkcg mismatch */
@@ -735,7 +736,7 @@ static void cgwb_bdi_unregister(struct backing_dev_info *bdi)
  */
 void wb_memcg_offline(struct mem_cgroup *memcg)
 {
-       struct list_head *memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
+       struct list_head *memcg_cgwb_list = &memcg->cgwb_list;
        struct bdi_writeback *wb, *next;
 
        spin_lock_irq(&cgwb_lock);
@@ -784,6 +785,21 @@ static void cgwb_bdi_register(struct backing_dev_info *bdi)
        spin_unlock_irq(&cgwb_lock);
 }
 
+static int __init cgwb_init(void)
+{
+       /*
+        * There can be many concurrent release work items overwhelming
+        * system_wq.  Put them in a separate wq and limit concurrency.
+        * There's no point in executing many of these in parallel.
+        */
+       cgwb_release_wq = alloc_workqueue("cgwb_release", 0, 1);
+       if (!cgwb_release_wq)
+               return -ENOMEM;
+
+       return 0;
+}
+subsys_initcall(cgwb_init);
+
 #else  /* CONFIG_CGROUP_WRITEBACK */
 
 static int cgwb_bdi_init(struct backing_dev_info *bdi)