Cc: Dmitry Monakhov <dmonakhov@...>, <torvalds@...>, <linux-fsdevel@...>, <linux-kernel@...>, Christoph Hellwig <hch@...>, Mel Gorman <mel@...>, William Lee Irwin III <wli@...>, David Chinner <dgc@...>, Badari Pulavarty <pbadari@...>, Maxim Levitsky <maximlevitsky@...>, Fengguang Wu <fengguang.wu@...>, swin wang <wangswin@...>, <totty.lu@...>, H. Peter Anvin <hpa@...>, <joern@...>, Eric W. Biederman <ebiederm@...>
Only the bottom part. Change controller, move disk, whatever. There are
lots of ways to change part of the IO path.
You pretty much hit the nail on the head there yourself. The io layer
_may_ coalesce them all together, but it may also stop at am arbitrary
point and put the remainder in another request.
This situation is different from submitting one huge piece, the above is
what has always happened regardless of whether the origin happens to be
a compound page or not.
--
Jens Axboe
-
