On Sun, 16 September 2007 00:30:32 +0200, Andrea Arcangeli wrote: > > Movable? I rather assume all slab allocations aren't movable. Then > slab defrag can try to tackle on users like dcache and inodes. Keep in > mind that with the exception of updatedb, those inodes/dentries will > be pinned and you won't move them, which is why I prefer to consider > them not movable too... since there's no guarantee they are. I have been toying with the idea of having seperate caches for pinned and movable dentries. Downside of such a patch would be the number of memcpy() operations when moving dentries from one cache to the other. Upside is that a fair amount of slab cache can be made movable. memcpy() is still faster than reading an object from disk. Most likely the current reaction to such a patch would be to shoot it down due to overhead, so I didn't pursue it. All I have is an old patch to seperate never-cached from possibly-cached dentries. It will increase the odds of freeing a slab, but provide no guarantee. But the point here is: dentries/inodes can be made movable if there are clear advantages to it. Maybe they should? Jörn -- Joern's library part 2: http://www.art.net/~hopkins/Don/unix-haters/tirix/embarrassing-memo.html - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
