Infrastructure to account dirty pages per cgroup and add dirty limit
interfaces in the cgroupfs:

 - Direct write-out: memory.dirty_ratio, memory.dirty_bytes

 - Background write-out: memory.dirty_background_ratio, 
memory.dirty_background_bytes

Signed-off-by: Andrea Righi <ari...@develer.com>
---
 include/linux/memcontrol.h |   87 +++++++++-
 mm/memcontrol.c            |  432 ++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 480 insertions(+), 39 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 44301c6..0602ec9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -19,12 +19,55 @@
 
 #ifndef _LINUX_MEMCONTROL_H
 #define _LINUX_MEMCONTROL_H
+
+#include <linux/writeback.h>
 #include <linux/cgroup.h>
+
 struct mem_cgroup;
 struct page_cgroup;
 struct page;
 struct mm_struct;
 
+/* Cgroup memory statistics items exported to the kernel */
+enum mem_cgroup_read_page_stat_item {
+       MEMCG_NR_DIRTYABLE_PAGES,
+       MEMCG_NR_RECLAIM_PAGES,
+       MEMCG_NR_WRITEBACK,
+       MEMCG_NR_DIRTY_WRITEBACK_PAGES,
+};
+
+/* File cache pages accounting */
+enum mem_cgroup_write_page_stat_item {
+       MEMCG_NR_FILE_MAPPED,           /* # of pages charged as file rss */
+       MEMCG_NR_FILE_DIRTY,            /* # of dirty pages in page cache */
+       MEMCG_NR_FILE_WRITEBACK,        /* # of pages under writeback */
+       MEMCG_NR_FILE_WRITEBACK_TEMP,   /* # of pages under writeback using
+                                          temporary buffers */
+       MEMCG_NR_FILE_UNSTABLE_NFS,     /* # of NFS unstable pages */
+
+       MEMCG_NR_FILE_NSTAT,
+};
+
+/* Dirty memory parameters */
+struct vm_dirty_param {
+       int dirty_ratio;
+       int dirty_background_ratio;
+       unsigned long dirty_bytes;
+       unsigned long dirty_background_bytes;
+};
+
+/*
+ * TODO: provide a validation check routine. And retry if validation
+ * fails.
+ */
+static inline void get_global_vm_dirty_param(struct vm_dirty_param *param)
+{
+       param->dirty_ratio = vm_dirty_ratio;
+       param->dirty_bytes = vm_dirty_bytes;
+       param->dirty_background_ratio = dirty_background_ratio;
+       param->dirty_background_bytes = dirty_background_bytes;
+}
+
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
 /*
  * All "charge" functions with gfp_mask should use GFP_KERNEL or
@@ -117,6 +160,25 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup 
*memcg,
 extern int do_swap_account;
 #endif
 
+extern bool mem_cgroup_has_dirty_limit(void);
+extern void get_vm_dirty_param(struct vm_dirty_param *param);
+extern s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item);
+
+extern void mem_cgroup_update_page_stat(struct page *page,
+                       enum mem_cgroup_write_page_stat_item idx, bool charge);
+
+static inline void mem_cgroup_inc_page_stat(struct page *page,
+               enum mem_cgroup_write_page_stat_item idx)
+{
+       mem_cgroup_update_page_stat(page, idx, true);
+}
+
+static inline void mem_cgroup_dec_page_stat(struct page *page,
+               enum mem_cgroup_write_page_stat_item idx)
+{
+       mem_cgroup_update_page_stat(page, idx, false);
+}
+
 static inline bool mem_cgroup_disabled(void)
 {
        if (mem_cgroup_subsys.disabled)
@@ -124,7 +186,6 @@ static inline bool mem_cgroup_disabled(void)
        return false;
 }
 
-void mem_cgroup_update_file_mapped(struct page *page, int val);
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
                                                gfp_t gfp_mask, int nid,
                                                int zid);
@@ -294,8 +355,18 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct 
task_struct *p)
 {
 }
 
-static inline void mem_cgroup_update_file_mapped(struct page *page,
-                                                       int val)
+static inline s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item 
item)
+{
+       return -ENOSYS;
+}
+
+static inline void mem_cgroup_inc_page_stat(struct page *page,
+                       enum mem_cgroup_write_page_stat_item idx)
+{
+}
+
+static inline void mem_cgroup_dec_page_stat(struct page *page,
+                       enum mem_cgroup_write_page_stat_item idx)
 {
 }
 
@@ -306,6 +377,16 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone 
*zone, int order,
        return 0;
 }
 
+static inline bool mem_cgroup_has_dirty_limit(void)
+{
+       return false;
+}
+
+static inline void get_vm_dirty_param(struct vm_dirty_param *param)
+{
+       get_global_vm_dirty_param(param);
+}
+
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a9fd736..ffcf37c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -80,14 +80,21 @@ enum mem_cgroup_stat_index {
        /*
         * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
         */
-       MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */
+       MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */
        MEM_CGROUP_STAT_RSS,       /* # of pages charged as anon rss */
-       MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
        MEM_CGROUP_STAT_PGPGIN_COUNT,   /* # of pages paged in */
        MEM_CGROUP_STAT_PGPGOUT_COUNT,  /* # of pages paged out */
        MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
        MEM_CGROUP_EVENTS,      /* incremented at every  pagein/pageout */
 
+       /* File cache pages accounting */
+       MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
+       MEM_CGROUP_STAT_FILE_DIRTY,   /* # of dirty pages in page cache */
+       MEM_CGROUP_STAT_WRITEBACK,   /* # of pages under writeback */
+       MEM_CGROUP_STAT_WRITEBACK_TEMP,   /* # of pages under writeback using
+                                               temporary buffers */
+       MEM_CGROUP_STAT_UNSTABLE_NFS,   /* # of NFS unstable pages */
+
        MEM_CGROUP_STAT_NSTATS,
 };
 
@@ -95,6 +102,19 @@ struct mem_cgroup_stat_cpu {
        s64 count[MEM_CGROUP_STAT_NSTATS];
 };
 
+/* Per cgroup page statistics */
+struct mem_cgroup_page_stat {
+       enum mem_cgroup_read_page_stat_item item;
+       s64 value;
+};
+
+enum {
+       MEM_CGROUP_DIRTY_RATIO,
+       MEM_CGROUP_DIRTY_BYTES,
+       MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
+       MEM_CGROUP_DIRTY_BACKGROUND_BYTES,
+};
+
 /*
  * per-zone information in memory controller.
  */
@@ -208,6 +228,9 @@ struct mem_cgroup {
 
        unsigned int    swappiness;
 
+       /* control memory cgroup dirty pages */
+       struct vm_dirty_param dirty_param;
+
        /* set when res.limit == memsw.limit */
        bool            memsw_is_minimum;
 
@@ -1033,6 +1056,157 @@ static unsigned int get_swappiness(struct mem_cgroup 
*memcg)
        return swappiness;
 }
 
+static bool dirty_param_is_valid(struct vm_dirty_param *param)
+{
+       if (param->dirty_ratio && param->dirty_bytes)
+               return false;
+       if (param->dirty_background_ratio && param->dirty_background_bytes)
+               return false;
+       return true;
+}
+
+static void __mem_cgroup_get_dirty_param(struct vm_dirty_param *param,
+                               struct mem_cgroup *mem)
+{
+       param->dirty_ratio = mem->dirty_param.dirty_ratio;
+       param->dirty_bytes = mem->dirty_param.dirty_bytes;
+       param->dirty_background_ratio = mem->dirty_param.dirty_background_ratio;
+       param->dirty_background_bytes = mem->dirty_param.dirty_background_bytes;
+}
+
+/*
+ * get_vm_dirty_param() - get dirty memory parameters of the current memcg
+ * @param:     a structure that is filled with the dirty memory settings
+ *
+ * The function fills @param with the current memcg dirty memory settings. If
+ * memory cgroup is disabled or in case of error the structure is filled with
+ * the global dirty memory settings.
+ */
+void get_vm_dirty_param(struct vm_dirty_param *param)
+{
+       struct mem_cgroup *memcg;
+
+       if (mem_cgroup_disabled()) {
+               get_global_vm_dirty_param(param);
+               return;
+       }
+       /*
+        * It's possible that "current" may be moved to other cgroup while we
+        * access cgroup. But precise check is meaningless because the task can
+        * be moved after our access and writeback tends to take long time.
+        * At least, "memcg" will not be freed under rcu_read_lock().
+        */
+       while (1) {
+               rcu_read_lock();
+               memcg = mem_cgroup_from_task(current);
+               if (likely(memcg))
+                       __mem_cgroup_get_dirty_param(param, memcg);
+               else
+                       get_global_vm_dirty_param(param);
+               rcu_read_unlock();
+               /*
+                * Since global and memcg vm_dirty_param are not protected we
+                * try to speculatively read them and retry if we get
+                * inconsistent values.
+                */
+               if (likely(dirty_param_is_valid(param)))
+                       break;
+       }
+}
+
+static inline bool mem_cgroup_can_swap(struct mem_cgroup *memcg)
+{
+       if (!do_swap_account)
+               return nr_swap_pages > 0;
+       return !memcg->memsw_is_minimum &&
+               (res_counter_read_u64(&memcg->memsw, RES_LIMIT) > 0);
+}
+
+static s64 mem_cgroup_get_local_page_stat(struct mem_cgroup *memcg,
+                               enum mem_cgroup_read_page_stat_item item)
+{
+       s64 ret;
+
+       switch (item) {
+       case MEMCG_NR_DIRTYABLE_PAGES:
+               ret = res_counter_read_u64(&memcg->res, RES_LIMIT) -
+                       res_counter_read_u64(&memcg->res, RES_USAGE);
+               /* Translate free memory in pages */
+               ret >>= PAGE_SHIFT;
+               ret += mem_cgroup_read_stat(memcg, LRU_ACTIVE_FILE) +
+                       mem_cgroup_read_stat(memcg, LRU_INACTIVE_FILE);
+               if (mem_cgroup_can_swap(memcg))
+                       ret += mem_cgroup_read_stat(memcg, LRU_ACTIVE_ANON) +
+                               mem_cgroup_read_stat(memcg, LRU_INACTIVE_ANON);
+               break;
+       case MEMCG_NR_RECLAIM_PAGES:
+               ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_FILE_DIRTY) +
+                       mem_cgroup_read_stat(memcg,
+                                       MEM_CGROUP_STAT_UNSTABLE_NFS);
+               break;
+       case MEMCG_NR_WRITEBACK:
+               ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+               break;
+       case MEMCG_NR_DIRTY_WRITEBACK_PAGES:
+               ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK) +
+                       mem_cgroup_read_stat(memcg,
+                               MEM_CGROUP_STAT_UNSTABLE_NFS);
+               break;
+       default:
+               BUG();
+               break;
+       }
+       return ret;
+}
+
+/*
+ * mem_cgroup_has_dirty_limit() - check if current memcg has local dirty limits
+ *
+ * Return true if the current memory cgroup has local dirty memory settings,
+ * false otherwise.
+ */
+bool mem_cgroup_has_dirty_limit(void)
+{
+       if (mem_cgroup_disabled())
+               return false;
+       return mem_cgroup_from_task(current) != NULL;
+}
+
+static int mem_cgroup_page_stat_cb(struct mem_cgroup *mem, void *data)
+{
+       struct mem_cgroup_page_stat *stat = (struct mem_cgroup_page_stat *)data;
+
+       stat->value += mem_cgroup_get_local_page_stat(mem, stat->item);
+       return 0;
+}
+
+/*
+ * mem_cgroup_page_stat() - get memory cgroup file cache statistics
+ * @item:      memory statistic item exported to the kernel
+ *
+ * Return the accounted statistic value, or a negative value in case of error.
+ */
+s64 mem_cgroup_page_stat(enum mem_cgroup_read_page_stat_item item)
+{
+       struct mem_cgroup_page_stat stat = {};
+       struct mem_cgroup *memcg;
+
+       rcu_read_lock();
+       memcg = mem_cgroup_from_task(current);
+       if (memcg) {
+               /*
+                * Recursively evaulate page statistics against all cgroup
+                * under hierarchy tree
+                */
+               stat.item = item;
+               mem_cgroup_walk_tree(memcg, &stat, mem_cgroup_page_stat_cb);
+       } else
+               stat.value = -EINVAL;
+       rcu_read_unlock();
+
+       return stat.value;
+}
+
 static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
 {
        int *val = data;
@@ -1344,36 +1518,86 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, 
gfp_t mask)
        return true;
 }
 
+static void __mem_cgroup_update_page_stat(struct page_cgroup *pc,
+                       enum mem_cgroup_write_page_stat_item idx, bool charge)
+{
+       struct mem_cgroup *mem = pc->mem_cgroup;
+
+       /*
+        * Set the opportune flags of page_cgroup and translate the public
+        * mem_cgroup_page_stat_index into the local mem_cgroup_stat_index.
+        *
+        * In this way we can export to the kernel only a restricted subset of
+        * memcg flags.
+        */
+       switch (idx) {
+       case MEMCG_NR_FILE_MAPPED:
+               if (charge)
+                       SetPageCgroupFileMapped(pc);
+               else
+                       ClearPageCgroupFileMapped(pc);
+               idx = MEM_CGROUP_STAT_FILE_MAPPED;
+               break;
+       case MEMCG_NR_FILE_DIRTY:
+               if (charge)
+                       SetPageCgroupDirty(pc);
+               else
+                       ClearPageCgroupDirty(pc);
+               idx = MEM_CGROUP_STAT_FILE_DIRTY;
+               break;
+       case MEMCG_NR_FILE_WRITEBACK:
+               if (charge)
+                       SetPageCgroupWriteback(pc);
+               else
+                       ClearPageCgroupWriteback(pc);
+               idx = MEM_CGROUP_STAT_WRITEBACK;
+               break;
+       case MEMCG_NR_FILE_WRITEBACK_TEMP:
+               if (charge)
+                       SetPageCgroupWritebackTemp(pc);
+               else
+                       ClearPageCgroupWritebackTemp(pc);
+               idx = MEM_CGROUP_STAT_WRITEBACK_TEMP;
+               break;
+       case MEMCG_NR_FILE_UNSTABLE_NFS:
+               if (charge)
+                       SetPageCgroupUnstableNFS(pc);
+               else
+                       ClearPageCgroupUnstableNFS(pc);
+               idx = MEM_CGROUP_STAT_UNSTABLE_NFS;
+               break;
+       default:
+               BUG();
+               break;
+       }
+       __this_cpu_add(mem->stat->count[idx], charge ? 1 : -1);
+}
+
 /*
- * Currently used to update mapped file statistics, but the routine can be
- * generalized to update other statistics as well.
+ * mem_cgroup_update_page_stat() - update memcg file cache's accounting
+ * @page:      the page involved in a file cache operation.
+ * @idx:       the particular file cache statistic.
+ * @charge:    true to increment, false to decrement the statistic specified
+ *             by @idx.
+ *
+ * Update memory cgroup file cache's accounting.
  */
-void mem_cgroup_update_file_mapped(struct page *page, int val)
+void mem_cgroup_update_page_stat(struct page *page,
+                       enum mem_cgroup_write_page_stat_item idx, bool charge)
 {
-       struct mem_cgroup *mem;
        struct page_cgroup *pc;
        unsigned long flags;
 
+       if (mem_cgroup_disabled())
+               return;
        pc = lookup_page_cgroup(page);
-       if (unlikely(!pc))
+       if (unlikely(!pc) || !PageCgroupUsed(pc))
                return;
-
        lock_page_cgroup(pc, flags);
-       mem = pc->mem_cgroup;
-       if (!mem)
-               goto done;
-
-       if (!PageCgroupUsed(pc))
-               goto done;
-
-       /*
-        * Preemption is already disabled. We can use __this_cpu_xxx
-        */
-       __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], val);
-
-done:
+       __mem_cgroup_update_page_stat(pc, idx, charge);
        unlock_page_cgroup(pc, flags);
 }
+EXPORT_SYMBOL_GPL(mem_cgroup_update_page_stat_unlocked);
 
 /*
  * size of first charge trial. "32" comes from vmscan.c's magic value.
@@ -1785,6 +2009,39 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup 
*mem,
        memcg_check_events(mem, pc->page);
 }
 
+/* Update file cache accounted statistics on task migration. */
+static void __mem_cgroup_update_file_stat(struct page_cgroup *pc,
+       struct mem_cgroup *from, struct mem_cgroup *to)
+{
+       struct page *page = pc->page;
+
+       if (!page_mapped(page) || PageAnon(page))
+               return;
+
+       if (PageCgroupFileMapped(pc)) {
+               __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
+               __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
+       }
+       if (PageCgroupDirty(pc)) {
+               __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_DIRTY]);
+               __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_DIRTY]);
+       }
+       if (PageCgroupWriteback(pc)) {
+               __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_WRITEBACK]);
+               __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_WRITEBACK]);
+       }
+       if (PageCgroupWritebackTemp(pc)) {
+               __this_cpu_dec(
+                       from->stat->count[MEM_CGROUP_STAT_WRITEBACK_TEMP]);
+               __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_WRITEBACK_TEMP]);
+       }
+       if (PageCgroupUnstableNFS(pc)) {
+               __this_cpu_dec(
+                       from->stat->count[MEM_CGROUP_STAT_UNSTABLE_NFS]);
+               __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_UNSTABLE_NFS]);
+       }
+}
+
 /**
  * __mem_cgroup_move_account - move account of the page
  * @pc:        page_cgroup of the page.
@@ -1805,22 +2062,14 @@ static void __mem_cgroup_commit_charge(struct 
mem_cgroup *mem,
 static void __mem_cgroup_move_account(struct page_cgroup *pc,
        struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
 {
-       struct page *page;
-
        VM_BUG_ON(from == to);
        VM_BUG_ON(PageLRU(pc->page));
        VM_BUG_ON(!PageCgroupLocked(pc));
        VM_BUG_ON(!PageCgroupUsed(pc));
        VM_BUG_ON(pc->mem_cgroup != from);
 
-       page = pc->page;
-       if (page_mapped(page) && !PageAnon(page)) {
-               /* Update mapped_file data for mem_cgroup */
-               preempt_disable();
-               __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
-               __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
-               preempt_enable();
-       }
+       __mem_cgroup_update_file_stat(pc, from, to);
+
        mem_cgroup_charge_statistics(from, pc, false);
        if (uncharge)
                /* This is not "cancel", but cancel_charge does all we need. */
@@ -1847,6 +2096,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
 {
        int ret = -EINVAL;
        unsigned long flags;
+
        lock_page_cgroup(pc, flags);
        if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
                __mem_cgroup_move_account(pc, from, to, uncharge);
@@ -3125,10 +3375,14 @@ static int mem_cgroup_move_charge_write(struct cgroup 
*cgrp,
 enum {
        MCS_CACHE,
        MCS_RSS,
-       MCS_FILE_MAPPED,
        MCS_PGPGIN,
        MCS_PGPGOUT,
        MCS_SWAP,
+       MCS_FILE_MAPPED,
+       MCS_FILE_DIRTY,
+       MCS_WRITEBACK,
+       MCS_WRITEBACK_TEMP,
+       MCS_UNSTABLE_NFS,
        MCS_INACTIVE_ANON,
        MCS_ACTIVE_ANON,
        MCS_INACTIVE_FILE,
@@ -3147,10 +3401,14 @@ struct {
 } memcg_stat_strings[NR_MCS_STAT] = {
        {"cache", "total_cache"},
        {"rss", "total_rss"},
-       {"mapped_file", "total_mapped_file"},
        {"pgpgin", "total_pgpgin"},
        {"pgpgout", "total_pgpgout"},
        {"swap", "total_swap"},
+       {"mapped_file", "total_mapped_file"},
+       {"filedirty", "dirty_pages"},
+       {"writeback", "writeback_pages"},
+       {"writeback_tmp", "writeback_temp_pages"},
+       {"nfs", "nfs_unstable"},
        {"inactive_anon", "total_inactive_anon"},
        {"active_anon", "total_active_anon"},
        {"inactive_file", "total_inactive_file"},
@@ -3169,8 +3427,6 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup 
*mem, void *data)
        s->stat[MCS_CACHE] += val * PAGE_SIZE;
        val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
        s->stat[MCS_RSS] += val * PAGE_SIZE;
-       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
-       s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
        val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
        s->stat[MCS_PGPGIN] += val;
        val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
@@ -3179,6 +3435,16 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup 
*mem, void *data)
                val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
                s->stat[MCS_SWAP] += val * PAGE_SIZE;
        }
+       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
+       s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
+       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_DIRTY);
+       s->stat[MCS_FILE_DIRTY] += val;
+       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK);
+       s->stat[MCS_WRITEBACK] += val;
+       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK_TEMP);
+       s->stat[MCS_WRITEBACK_TEMP] += val;
+       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_UNSTABLE_NFS);
+       s->stat[MCS_UNSTABLE_NFS] += val;
 
        /* per zone stat */
        val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
@@ -3540,6 +3806,63 @@ unlock:
        return ret;
 }
 
+static u64 mem_cgroup_dirty_read(struct cgroup *cgrp, struct cftype *cft)
+{
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+       switch (cft->private) {
+       case MEM_CGROUP_DIRTY_RATIO:
+               return memcg->dirty_param.dirty_ratio;
+       case MEM_CGROUP_DIRTY_BYTES:
+               return memcg->dirty_param.dirty_bytes;
+       case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
+               return memcg->dirty_param.dirty_background_ratio;
+       case MEM_CGROUP_DIRTY_BACKGROUND_BYTES:
+               return memcg->dirty_param.dirty_background_bytes;
+       default:
+               BUG();
+       }
+}
+
+static int
+mem_cgroup_dirty_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+       int type = cft->private;
+
+       if (cgrp->parent == NULL)
+               return -EINVAL;
+       if ((type == MEM_CGROUP_DIRTY_RATIO ||
+               type == MEM_CGROUP_DIRTY_BACKGROUND_RATIO) && val > 100)
+               return -EINVAL;
+       /*
+        * TODO: provide a validation check routine. And retry if validation
+        * fails.
+        */
+       switch (type) {
+       case MEM_CGROUP_DIRTY_RATIO:
+               memcg->dirty_param.dirty_ratio = val;
+               memcg->dirty_param.dirty_bytes = 0;
+               break;
+       case MEM_CGROUP_DIRTY_BYTES:
+               memcg->dirty_param.dirty_ratio  = 0;
+               memcg->dirty_param.dirty_bytes = val;
+               break;
+       case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
+               memcg->dirty_param.dirty_background_ratio = val;
+               memcg->dirty_param.dirty_background_bytes = 0;
+               break;
+       case MEM_CGROUP_DIRTY_BACKGROUND_BYTES:
+               memcg->dirty_param.dirty_background_ratio = 0;
+               memcg->dirty_param.dirty_background_bytes = val;
+               break;
+       default:
+               BUG();
+               break;
+       }
+       return 0;
+}
+
 static struct cftype mem_cgroup_files[] = {
        {
                .name = "usage_in_bytes",
@@ -3591,6 +3914,30 @@ static struct cftype mem_cgroup_files[] = {
                .write_u64 = mem_cgroup_swappiness_write,
        },
        {
+               .name = "dirty_ratio",
+               .read_u64 = mem_cgroup_dirty_read,
+               .write_u64 = mem_cgroup_dirty_write,
+               .private = MEM_CGROUP_DIRTY_RATIO,
+       },
+       {
+               .name = "dirty_bytes",
+               .read_u64 = mem_cgroup_dirty_read,
+               .write_u64 = mem_cgroup_dirty_write,
+               .private = MEM_CGROUP_DIRTY_BYTES,
+       },
+       {
+               .name = "dirty_background_ratio",
+               .read_u64 = mem_cgroup_dirty_read,
+               .write_u64 = mem_cgroup_dirty_write,
+               .private = MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
+       },
+       {
+               .name = "dirty_background_bytes",
+               .read_u64 = mem_cgroup_dirty_read,
+               .write_u64 = mem_cgroup_dirty_write,
+               .private = MEM_CGROUP_DIRTY_BACKGROUND_BYTES,
+       },
+       {
                .name = "move_charge_at_immigrate",
                .read_u64 = mem_cgroup_move_charge_read,
                .write_u64 = mem_cgroup_move_charge_write,
@@ -3849,8 +4196,21 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct 
cgroup *cont)
        mem->last_scanned_child = 0;
        spin_lock_init(&mem->reclaim_param_lock);
 
-       if (parent)
+       if (parent) {
                mem->swappiness = get_swappiness(parent);
+               mem->dirty_param = parent->dirty_param;
+       } else {
+               while (1) {
+                       get_global_vm_dirty_param(&mem->dirty_param);
+                       /*
+                        * Since global dirty parameters are not protected we
+                        * try to speculatively read them and retry if we get
+                        * inconsistent values.
+                        */
+                       if (likely(dirty_param_is_valid(&mem->dirty_param)))
+                               break;
+               }
+       }
        atomic_set(&mem->refcnt, 1);
        mem->move_charge_at_immigrate = 0;
        mutex_init(&mem->thresholds_lock);
-- 
1.6.3.3

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