[PATCH 4/7] page-writeback: pass in '0' for nr_pages writeback in laptop mode

From: Jens Axboe
Date: Wed Sep 20 2017 - 11:34:12 EST


Laptop mode really wants to writeback the number of dirty
pages and inodes. Instead of calculating this in the caller,
just pass in 0 and let wakeup_flusher_threads() handle it.

Use the new wakeup_flusher_threads_bdi() instead of rolling
our own. This changes the writeback to not be range cyclic,
but that should not matter for laptop mode flush-all
semantics.

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Tested-by: Chris Mason <clm@xxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
mm/page-writeback.c | 17 +----------------
1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0b9c5cbe8eba..8d1fc593bce8 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1980,23 +1980,8 @@ int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
void laptop_mode_timer_fn(unsigned long data)
{
struct request_queue *q = (struct request_queue *)data;
- int nr_pages = global_node_page_state(NR_FILE_DIRTY) +
- global_node_page_state(NR_UNSTABLE_NFS);
- struct bdi_writeback *wb;

- /*
- * We want to write everything out, not just down to the dirty
- * threshold
- */
- if (!bdi_has_dirty_io(q->backing_dev_info))
- return;
-
- rcu_read_lock();
- list_for_each_entry_rcu(wb, &q->backing_dev_info->wb_list, bdi_node)
- if (wb_has_dirty_io(wb))
- wb_start_writeback(wb, nr_pages, true,
- WB_REASON_LAPTOP_TIMER);
- rcu_read_unlock();
+ wakeup_flusher_threads_bdi(q->backing_dev_info, WB_REASON_LAPTOP_TIMER);
}

/*
--
2.7.4