Peter Zijlstra a écrit : > On Wed, 2008-05-21 at 12:25 +0200, Louis Rilling wrote: > >>> http://programming.kicks-ass.net/kernel-patches/concurrent-pagecache/23-rc1-rt/radix-concurrent-lockdep.patch >> Thanks for pointing this out. >> >> Yes this could solve part of the issue, at the price of duplicating the >> inode mutex class. However, this still does not solve the issue when >> deleting config_groups, since in that case all nodes of the tree are >> locked. Thinking about adding lockdep support for concurrent locking of >> the direct children of a node in a tree... > > Why doesn't sysfs have this problem? - the code says configfs was > derived from sysfs.
Perhaps because sysfs is driven from the kernel, where behaviors can be controlled, while in configfs only userspace creates/removes directories. > > Also, do you really need to hold all locks when removing something? > sound like a bit overdone. Also realise there is a maximum number of > held locks - various people have already requested it to be increased or > made dynamic. We're reluctant in doing so because we feel lock chains > should not be of unlimited length. The deeper the chains the bigger the > PI overhead etc.. I did not write configfs, so I can only observe that a whole inode tree is locked when removing a directory hierarchy. I suspect that this is intended to provide userspace and client sub-systems with some atomic semantics... > > As to modifying lockdep - it currently doesn't know about trees and > teaching it about them isn't easy. That was my guess. -- Dr Louis Rilling Kerlabs Skype: louis.rilling Batiment Germanium Phone: (+33|0) 6 80 89 08 23 80 avenue des Buttes de Coesmes http://www.kerlabs.com/ 35700 Rennes _______________________________________________ Ocfs2-devel mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-devel
