[PATCH 10/18] writeback: add dirty_throttle_control->dom

Tejun Heo
2015-03-23T05:11:30Z

Currently all dirty throttle operations use global_wb_domain; however,
cgroup writeback support requires considering per-memcg wb_domain too.
This patch adds dirty_throttle_control->dom and updates functions
which are directly using globabl_wb_domain to use it instead.

As this makes global_update_bandwidth() a misnomer, the function is
renamed to domain_update_bandwidth().

This patch doesn't introduce any behavioral changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Thelen <gthelen@google.com>
---
mm/page-writeback.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 1f216cf..840b8f2 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -126,6 +126,9 @@ struct wb_domain global_wb_domain;

/* consolidated parameters for balance_dirty_pages() and its subroutines */
struct dirty_throttle_control {
+#ifdef CONFIG_CGROUP_WRITEBACK
+ struct wb_domain *dom;
+#endif
struct bdi_writeback *wb;
struct fprop_local_percpu *wb_completions;

@@ -140,7 +143,7 @@ struct dirty_throttle_control {
unsigned long pos_ratio;
};

-#define GDTC_INIT(__wb) .wb = (__wb), \
+#define DTC_INIT_COMMON(__wb) .wb = (__wb), \
.wb_completions = &(__wb)->completions

/*
@@ -152,6 +155,14 @@ struct dirty_throttle_control {

#ifdef CONFIG_CGROUP_WRITEBACK

+#define GDTC_INIT(__wb) .dom = &global_wb_domain, \
+ DTC_INIT_COMMON(__wb)
+
+static struct wb_domain *dtc_dom(struct dirty_throttle_control *dtc)
+{
+ return dtc->dom;
+}
+
static void wb_min_max_ratio(struct bdi_writeback *wb,
unsigned long *minp, unsigned long *maxp)
{
@@ -181,6 +192,13 @@ static void wb_min_max_ratio(struct bdi_writeback *wb,

#else /* CONFIG_CGROUP_WRITEBACK */

+#define GDTC_INIT(__wb) DTC_INIT_COMMON(__wb)
+
+static struct wb_domain *dtc_dom(struct dirty_throttle_control *dtc)
+{
+ return &global_wb_domain;
+}
+
static void wb_min_max_ratio(struct bdi_writeback *wb,
unsigned long *minp, unsigned long *maxp)
{
@@ -583,7 +601,7 @@ static unsigned long hard_dirty_limit(unsigned long thresh)
*/
static unsigned long __wb_dirty_limit(struct dirty_throttle_control *dtc)
{
- struct wb_domain *dom = &global_wb_domain;
+ struct wb_domain *dom = dtc_dom(dtc);
unsigned long dirty = dtc->dirty;
u64 wb_dirty;
long numerator, denominator;
@@ -952,7 +970,7 @@ out:

static void update_dirty_limit(struct dirty_throttle_control *dtc)
{
- struct wb_domain *dom = &global_wb_domain;
+ struct wb_domain *dom = dtc_dom(dtc);
unsigned long thresh = dtc->thresh;
unsigned long limit = dom->dirty_limit;

@@ -979,10 +997,10 @@ update:
dom->dirty_limit = limit;
}

-static void global_update_bandwidth(struct dirty_throttle_control *dtc,
+static void domain_update_bandwidth(struct dirty_throttle_control *dtc,
unsigned long now)
{
- struct wb_domain *dom = &global_wb_domain;
+ struct wb_domain *dom = dtc_dom(dtc);

/*
* check locklessly first to optimize away locking for the most time
@@ -1190,7 +1208,7 @@ static void __wb_update_bandwidth(struct dirty_throttle_control *dtc,
goto snapshot;

if (update_ratelimit) {
- global_update_bandwidth(dtc, now);
+ domain_update_bandwidth(dtc, now);
wb_update_dirty_ratelimit(dtc, dirtied, elapsed);
}
wb_update_write_bandwidth(wb, elapsed, written);
--
2.1.0