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authorJens Axboe <jaxboe@fusionio.com>2011-04-12 12:28:28 +0400
committerJens Axboe <jaxboe@fusionio.com>2011-04-12 12:28:28 +0400
commitdc6d36c9710d1fed42d1bbe7d8e4f742abd844c6 (patch)
tree88062deeeb7f8d6973056422f08d47f8c5a27c51
parentf75664570d8b75469cc468f23c2b27220984983b (diff)
downloadlinux-dc6d36c9710d1fed42d1bbe7d8e4f742abd844c6.tar.xz
block: readd plug trace event
This was removed with the queue plug state. But we can easily readd by checking if this is the first request going to this queue. It's good information to have when tracing to see how effective the plugging is. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
-rw-r--r--block/blk-core.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 76850fc9cf23..52e756c526be 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1311,7 +1311,15 @@ get_rq:
plug = current->plug;
if (plug) {
- if (!plug->should_sort && !list_empty(&plug->list)) {
+ /*
+ * If this is the first request added after a plug, fire
+ * of a plug trace. If others have been added before, check
+ * if we have multiple devices in this plug. If so, make a
+ * note to sort the list before dispatch.
+ */
+ if (list_empty(&plug->list))
+ trace_block_plug(q);
+ else if (!plug->should_sort) {
struct request *__rq;
__rq = list_entry_rq(plug->list.prev);