[PATCH -mmotm 4/5] memcg: dirty pages accounting and limiting infrastructure

From: Andrea Righi
Date: Tue Mar 09 2010 - 18:01:39 EST

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 <arighi@xxxxxxxxxxx>
---
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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