Hi Jeff, I've dropped the spinlock conversion for the time beeing. Maybe the last patch which changes the usage of blocked_lock_lock is still useful. And in case I can convince of the spinlock conversion it can easliy done on top of it. I think it makes it also simpler to review doing it this after all. cheers, daniel v2: - added a few lockdep assertion - dropped spinlock conversion v1: - rebased on v3.19-8975-g3d88348 - splittet into smaller pieces - fixed a wrong usage of __locks_insert/delete_block() and it's posix version - added seqfile helpers to avoid ugly open coded version Original cover letter: I am looking at how to get rid of lglock. Reason being -rt is not too happy with that lock, especially that it uses arch_spinlock_t and therefore it is not changed into a mutex on -rt. I know no change is accepted only fixing something for -rt alone. So here my attempt to make things faster for mainline and fixing -rt. There are two users of lglock at this point. fs/locks.c and kernel/stop_machine.c I presume the fs/locks is the more interesting one in respect of performance. Let's have a look at that one first. The lglock version of file_lock_lock is used in combination of blocked_lock_lock to protect file_lock's fl_link, fl_block, fl_next, blocked_hash and the percpu file_lock_list. The plan is to reorganize the usage of the locks and what they protect so that the usage of the global blocked_lock_lock is reduced. Whenever we insert a new lock we are going to grab besides the i_lock also the corresponding percpu file_lock_lock. The global blocked_lock_lock is only used when blocked_hash is involved. file_lock_list exists to be being able to produce the content of /proc/locks. For listing the all locks it seems a bit excessive to grab all locks at once. We should be okay just grabbing the corresponding lock when iterating over the percpu file_lock_list. file_lock_lock protects now file_lock_list and fl_link, fl_block and fl_next allone. That means we need to define which file_lock_lock is used for all waiters. Luckely, fl_link_cpu can be reused for fl_block and fl_next. I haven't found a good way around for the open coded seq_ops (locks_start, locks_next, locks_stop). Maybe someone has good idea how to handle with the locks. For performance testing I used git://git.samba.org/jlayton/lockperf.git and for correctness https://github.com/linux-test-project/ltp/tree/master/testcases/network/nfsv4/locks In case you are missing the posix03 results, my machine doesn't like it too much. The load brings it to its knees due to the very high load. Propably I need different parameters. I didn't run excessive tests so far, because I am waiting for getting access on a bigger box compared to my small i7-4850HQ system. I hope to see larger improvements when there are more cores involved. [...] Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Jeff Layton <jlayton@xxxxxxxxxxxxxxx> Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx> Cc: linux-fsdevel@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Daniel Wagner (4): locks: Remove unnecessary IS_POSIX test locks: Add lockdep assertion for blocked_lock_lock locks: Split insert/delete block functions into flock/posix parts locks: Use blocked_lock_lock only to protect blocked_hash fs/locks.c | 124 +++++++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 84 insertions(+), 40 deletions(-) -- 2.1.0 -- 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
