From dc6d36c9710d1fed42d1bbe7d8e4f742abd844c6 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 12 Apr 2011 10:28:28 +0200 Subject: [PATCH] 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 --- block/blk-core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) 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);