On Fri, May 14, 2010 at 05:24:18PM +1000, Dave Chinner wrote: > > This series reworks the filesystem shrinkers. We currently have a > set of issues with the current filesystem shrinkers: > > 1. There is an dependency between dentry and inode cache > shrinking that is only implicitly defined by the order of > shrinker registration. > 2. The shrinkers need to walk the superblock list and pin > the superblock to avoid unmount races with the sb going > away. > 3. The dentry cache uses per-superblock LRUs and proportions > reclaim between all the superblocks which means we are > doing breadth based reclaim. This means we touch every > superblock for every shrinker call, and may only reclaim > a single dentry at a time from a given superblock. > 4. The inode cache has a global LRU, so it has different > reclaim patterns to the dentry cache, despite the fact > that the dentry cache is generally the only thing that > pins inodes in memory. > 5. Filesystems need to register their own shrinkers for > caches and can't co-ordinate them with the dentry and > inode cache shrinkers. NAK in that form; sb refcounting and iterators had been reworked for .34, so at least it needs rediff on top of that. What's more, it's very obviously broken wrt locking - you are unregistering a shrinker from __put_super(). I.e. grab rwsem exclusively under a spinlock. Essentially, you've turned dropping a _passive_ reference to superblock (currently an operation safe in any context) into an operation allowed only when no fs or vm locks are held by caller. Not going to work... -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>