From 75bb4625bb78d6a2d879dcb6a7d482861295765b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 28 May 2014 10:15:41 -0600 Subject: blk-mq: add file comments and update copyright notices None of the blk-mq files have an explanatory comment at the top for what that particular file does. Add that and add appropriate copyright notices as well. Signed-off-by: Jens Axboe --- block/blk-mq-tag.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'block/blk-mq-tag.c') diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 0d0640d38a06..d90c4aeb7dd3 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -1,3 +1,15 @@ +/* + * Fast and scalable bitmap tagging variant. Uses sparser bitmaps spread + * over multiple cachelines to avoid ping-pong between multiple submitters + * or submitter and completer. Uses rolling wakeups to avoid falling of + * the scaling cliff when we run out of tags and have to start putting + * submitters to sleep. + * + * Uses active queue tracking to support fairer distribution of tags + * between multiple submitters when a shared tag map is used. + * + * Copyright (C) 2013-2014 Jens Axboe + */ #include #include #include -- cgit v1.2.3