laptop-mode: Make flushes per-device

One of the features of laptop-mode is that it forces a writeout of dirty
pages if something else triggers a physical read or write from a device.
The current implementation flushes pages on all devices, rather than only
the one that triggered the flush. This patch alters the behaviour so that
only the recently accessed block device is flushed, preventing other
disks being spun up for no terribly good reason.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 1d94f15d7f0d..4b1b29ef2cb0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -451,6 +451,7 @@ void blk_cleanup_queue(struct request_queue *q)
          */
         blk_sync_queue(q);
 
+        del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
         mutex_lock(&q->sysfs_lock);
         queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
         mutex_unlock(&q->sysfs_lock);
@@ -511,6 +512,8 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
                 return NULL;
         }
 
+        setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
+                    laptop_mode_timer_fn, (unsigned long) q);
         init_timer(&q->unplug_timer);
         setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
         INIT_LIST_HEAD(&q->timeout_list);
@@ -2101,7 +2104,7 @@ static void blk_finish_request(struct request *req, int error)
         BUG_ON(blk_queued_rq(req));
 
         if (unlikely(laptop_mode) && blk_fs_request(req))
-                laptop_io_completion();
+                laptop_io_completion(&req->q->backing_dev_info);
 
         blk_delete_timer(req);