diff options
Diffstat (limited to 'block/blk-mq-tag.c')
| -rw-r--r-- | block/blk-mq-tag.c | 12 |
1 files changed, 12 insertions, 0 deletions
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 <linux/kernel.h> #include <linux/module.h> #include <linux/random.h> |