[PATCH 3/3] PowerTOP would like to be able to show who is keeping the disk busy by dirtying data. The most logical spot for this is in the vfs in the mark_inode_dirty() function, doing this on the block level is not possible because by the time the IO hits the block layer the guilty party can no longer be found ("kjournald" and "pdflush" are not useful answers to "who caused this file to be dirty).