From b57d74aff9ab92fbfb7c197c384d1adfa2827b2e Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Thu, 1 Sep 2016 10:20:33 -0600
Subject: [PATCH] writeback: track if we're sleeping on progress in
balance_dirty_pages()
Note in the bdi_writeback structure whenever a task ends up sleeping
waiting for progress. We can use that information in the lower layers
to increase the priority of writes.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
include/linux/backing-dev-defs.h | 2 ++
mm/backing-dev.c | 1 +
mm/page-writeback.c | 1 +
3 files changed, 4 insertions(+)
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index c357f27d54835..dc5f76d7f648b 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -116,6 +116,8 @@ struct bdi_writeback {
struct list_head work_list;
struct delayed_work dwork; /* work item used for writeback */
+ unsigned long dirty_sleep; /* last wait */
+
struct list_head bdi_node; /* anchored at bdi->wb_list */
#ifdef CONFIG_CGROUP_WRITEBACK
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8fde443f36d77..3bfed5ab2475c 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -310,6 +310,7 @@ static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
spin_lock_init(&wb->work_lock);
INIT_LIST_HEAD(&wb->work_list);
INIT_DELAYED_WORK(&wb->dwork, wb_workfn);
+ wb->dirty_sleep = jiffies;
wb->congested = wb_congested_get_create(bdi, blkcg_id, gfp);
if (!wb->congested)
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 439cc63ad903f..52e2f8e3b4721 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1778,6 +1778,7 @@ static void balance_dirty_pages(struct address_space *mapping,
pause,
start_time);
__set_current_state(TASK_KILLABLE);
+ wb->dirty_sleep = now;
io_schedule_timeout(pause);
current->dirty_paused_when = now + pause;
--
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