On Tue, Jan 10, 2012 at 05:22:22PM +0100, Miklos Szeredi wrote: > On Tue, Jan 10, 2012 at 5:00 PM, Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Jan 10, 2012 at 2:05 AM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > >> > >> I tested Dave's patch and the bug can still be easily reproduced. > >> > >> And that's to be expected, as the intermediate "being on the lru" > >> state that Dave's patch eliminates doesn't play a fundamental part in > >> the mechanism of the livelock. It does eliminate one trylock, but > >> that's not the one critical to this bug (removing it is a very good > >> idea anyway). > >> > >> The critical trylock here is the one in dentry_kill() which tries to > >> lock the parent. > > > > Ok. Here's your patch munged for current -git. You've got most of a > > changelog, can you send this out with the right subject and a > > sign-off, and re-test with the current git just to make sure. > > See the one with the subject "vfs: fix shrink_dcache_parent() > livelock" I sent out a bit earlier. > > You didn't quite get it right: the flag now needs to be set in > select_parent() not prune_dcache_sb(). > > I think prune_dcache_sb() doesn't need this logic (although it > wouldn't hurt either) because that one is called from the slab > shrinkers and those are protected from being run multiple times in > parallel, I hope. Shrinkers can be called in parallel by memory reclaim on different CPUs. The only thing serialising them is the LRU locks. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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
