On Sun, 2007-01-28 at 15:11 +0000, Christoph Hellwig wrote: > On Sun, Jan 28, 2007 at 02:43:25PM +0000, Christoph Hellwig wrote: > > On Sun, Jan 28, 2007 at 12:51:18PM +0100, Peter Zijlstra wrote: > > > This patch-set breaks up the global file_list_lock which was found to be a > > > severe contention point under basically any filesystem intensive workload. > > > > Benchmarks, please. Where exactly do you see contention for this? > > > > > > filesystem intensive workload apparently means namespace operation heavy > > workload, right? The biggest bottleneck I've seen with those is dcache > > lock. > > > > Even if this is becoming a real problem there must be simpler ways to fix > > this than introducing various new locking primitives and all kinds of > > complexity. > > One good way to fix scalability without all this braindamage is > to get rid of sb->s_files. Current uses are: > > - fs/dquot.c:add_dquot_ref() > > This performs it's actual operation on inodes. We should > be able to check inode->i_writecount to see which inodes > need quota initialization. > > - fs/file_table.c:fs_may_remount_ro() > > This one is gone in Dave Hansens per-mountpoint r/o patchkit > > - fs/proc/generic.c:proc_kill_inodes() > > This can be done with a list inside procfs. > > - fs/super.c:mark_files_ro() > > This one is only used for do_emergency_remount(), which is > and utter hack. It might be much better to just deny any > kind of write access through a superblock flag here. > > - fs/selinuxfs.c:sel_remove_bools() > > Utter madness. I have no idea how this ever got merged. > Maybe the selinux folks can explain what crack they were > on when writing this. The problem would go away with > a generic rewoke infrastructure.
It was modeled after proc_kill_inodes(), as noted in the comments. So if you have a suitable replacement for proc_kill_inodes(), you can apply the same approach to sel_remove_bools(). > > Once sb->s_files is gone we can also kill of fu_list entirely and > replace it by a list head entirely in the tty code and make the lock > for it per-tty. -- Stephen Smalley National Security Agency - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
