Add an memcg parameter to bdi_start_background_writeback(). If a memcg
is specified then the resulting background writeback call to
wb_writeback() will run until the memcg dirty memory usage drops below
the memcg background limit. This is used when balancing memcg dirty
memory with mem_cgroup_balance_dirty_pages().
If the memcg parameter is not specified, then background writeback runs
globally system dirty memory usage falls below the system background
limit.
Signed-off-by: Greg Thelen <gthelen@xxxxxxxxxx>
---
fs/fs-writeback.c | 63 ++++++++++++++++++++----------------------
include/linux/backing-dev.h | 3 +-
mm/memcontrol.c | 2 +-
mm/page-writeback.c | 2 +-
4 files changed, 34 insertions(+), 36 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 59c6e49..975741d 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -20,6 +20,7 @@
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/mm.h>
+#include <linux/memcontrol.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/writeback.h>
@@ -35,6 +36,7 @@
struct wb_writeback_work {
long nr_pages;
struct super_block *sb;
+ struct mem_cgroup *mem_cgroup; /* NULL for global (root cgroup) */
enum writeback_sync_modes sync_mode;
unsigned int for_kupdate:1;
unsigned int range_cyclic:1;
@@ -113,7 +115,8 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
static void
__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
- bool range_cyclic)
+ bool range_cyclic, bool for_background,
+ struct mem_cgroup *mem_cgroup)
{
struct wb_writeback_work *work;
@@ -133,6 +136,8 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
work->sync_mode = WB_SYNC_NONE;
work->nr_pages = nr_pages;
work->range_cyclic = range_cyclic;
+ work->for_background = for_background;
+ work->mem_cgroup = mem_cgroup;
bdi_queue_work(bdi, work);
}
@@ -150,7 +155,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
*/
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
{
- __bdi_start_writeback(bdi, nr_pages, true);
+ __bdi_start_writeback(bdi, nr_pages, true, false, NULL);
}
/**
@@ -163,16 +168,10 @@ void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
* some IO is happening if we are over background dirty threshold.
* Caller need not hold sb s_umount semaphore.
*/
-void bdi_start_background_writeback(struct backing_dev_info *bdi)
+void bdi_start_background_writeback(struct backing_dev_info *bdi,
+ struct mem_cgroup *mem_cgroup)
{
- /*
- * We just wake up the flusher thread. It will perform background
- * writeback as soon as there is no other work to do.
- */
- trace_writeback_wake_background(bdi);
- spin_lock_bh(&bdi->wb_lock);
- bdi_wakeup_flusher(bdi);
- spin_unlock_bh(&bdi->wb_lock);
+ __bdi_start_writeback(bdi, LONG_MAX, true, true, mem_cgroup);
}
/*
@@ -593,10 +592,22 @@ static void __writeback_inodes_sb(struct super_block *sb,
*/
#define MAX_WRITEBACK_PAGES 1024
-static inline bool over_bground_thresh(void)
+static inline bool over_bground_thresh(struct mem_cgroup *mem_cgroup)
{
unsigned long background_thresh, dirty_thresh;
+ if (mem_cgroup) {
+ struct dirty_info info;
+
+ if (!mem_cgroup_hierarchical_dirty_info(
+ determine_dirtyable_memory(), false,
+ mem_cgroup, &info))
+ return false;
+
+ return info.nr_file_dirty +
+ info.nr_unstable_nfs > info.background_thresh;
+ }
+
global_dirty_limits(&background_thresh, &dirty_thresh);
return (global_page_state(NR_FILE_DIRTY) +
@@ -683,7 +694,8 @@ static long wb_writeback(struct bdi_writeback *wb,
* For background writeout, stop when we are below the
* background dirty threshold
*/
- if (work->for_background && !over_bground_thresh())
+ if (work->for_background &&
+ !over_bground_thresh(work->mem_cgroup))
break;
wbc.more_io = 0;
@@ -761,23 +773,6 @@ static unsigned long get_nr_dirty_pages(void)
get_nr_dirty_inodes();
}
-static long wb_check_background_flush(struct bdi_writeback *wb)
-{
- if (over_bground_thresh()) {
-
- struct wb_writeback_work work = {
- .nr_pages = LONG_MAX,
- .sync_mode = WB_SYNC_NONE,
- .for_background = 1,
- .range_cyclic = 1,
- };
-
- return wb_writeback(wb, &work);
- }
-
- return 0;
-}
-
static long wb_check_old_data_flush(struct bdi_writeback *wb)
{
unsigned long expired;
@@ -839,15 +834,17 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
*/
if (work->done)
complete(work->done);
- else
+ else {
+ if (work->mem_cgroup)
+ mem_cgroup_bg_writeback_done(work->mem_cgroup);
kfree(work);
+ }
}
/*
* Check for periodic writeback, kupdated() style
*/
wrote += wb_check_old_data_flush(wb);
- wrote += wb_check_background_flush(wb);
clear_bit(BDI_writeback_running, &wb->bdi->state);
return wrote;
@@ -934,7 +931,7 @@ void wakeup_flusher_threads(long nr_pages)
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
if (!bdi_has_dirty_io(bdi))
continue;
- __bdi_start_writeback(bdi, nr_pages, false);
+ __bdi_start_writeback(bdi, nr_pages, false, false, NULL);
}
rcu_read_unlock();
}
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 4ce34fa..f794604 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -103,7 +103,8 @@ int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
void bdi_unregister(struct backing_dev_info *bdi);
int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
-void bdi_start_background_writeback(struct backing_dev_info *bdi);
+void bdi_start_background_writeback(struct backing_dev_info *bdi,
+ struct mem_cgroup *mem_cgroup);
int bdi_writeback_thread(void *data);
int bdi_has_dirty_io(struct backing_dev_info *bdi);
void bdi_arm_supers_timer(void);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 25dc077..41ba94f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1489,7 +1489,7 @@ void mem_cgroup_balance_dirty_pages(struct address_space *mapping,
* mem_cgroup_bg_writeback_done().
*/
css_get(&memcg->css);
- bdi_start_background_writeback(bdi);
+ bdi_start_background_writeback(bdi, memcg);
}
/* continue walking up hierarchy enabled parents */
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index f6a8dd6..492c3db 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -597,7 +597,7 @@ static void balance_dirty_pages(struct address_space *mapping,
*/
if ((laptop_mode && pages_written) ||
(!laptop_mode && (nr_reclaimable > background_thresh)))
- bdi_start_background_writeback(bdi);
+ bdi_start_background_writeback(bdi, NULL);
}
void set_page_dirty_balance(struct page *page, int page_mkwrite)
--
1.7.3.1
--
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