Messages in this thread | | | Date | Sat, 3 May 2014 19:25:28 +0100 | From | Al Viro <> | Subject | Re: dcache shrink list corruption? |
| |
On Sat, May 03, 2014 at 11:07:57AM -0700, Linus Torvalds wrote: > Sure, umount itself should be serialized by the sb lock, so there > should be only one umount dentry collector. But why wouldn't there be > shrinkers active due to memory pressure? > > generic_unmount_super() is called by ->kill_sb(), which is done > *before* the superblock shrinker is unregistered So any memory > pressure during that will cause dentries to be shrunk other ways. > > What am I missing?
This: if (!grab_super_passive(sb)) return SHRINK_STOP; before calling prune_dcache_sb(). grab_super_passive() returns with ->s_umount held shared on success (with down_read_trylock()) and ->kill_sb() is called only with ->s_umount held exclusive.
| |