On Tue, Aug 02, 2016 at 05:42:23PM +0300, Nikolay Borisov wrote: > Currently when /proc/locks is read it will show all the file locks > which are currently created on the machine. On containers, hosted > on busy servers this means that doing lsof can be very slow. I > observed up to 5 seconds stalls reading 50k locks,
Do you mean just that the reading process itself was blocked, or that others were getting stuck on blocked_lock_lock? (And what process was actually reading /proc/locks, out of curiosity?) > while the container > itself had only a small number of relevant entries. Fix it by > filtering the locks listed by the pidns of the current process > and the process which created the lock. Thanks, that's interesting. So you show a lock if it was created by someone in the current pid namespace. With a special exception for the init namespace so that If a filesystem is shared between containers that means you won't necessarily be able to figure out from within a container which lock is conflicting with your lock. (I don't know if that's really a problem. I'm unfortunately short on evidence aobut what people actually use /proc/locks for....) --b. > > Signed-off-by: Nikolay Borisov <[email protected]> > --- > fs/locks.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/fs/locks.c b/fs/locks.c > index 6333263b7bc8..53e96df4c583 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -2615,9 +2615,17 @@ static int locks_show(struct seq_file *f, void *v) > { > struct locks_iterator *iter = f->private; > struct file_lock *fl, *bfl; > + struct pid_namespace *pid_ns = task_active_pid_ns(current); > + > > fl = hlist_entry(v, struct file_lock, fl_link); > > + pr_info ("Current pid_ns: %p init_pid_ns: %p, fl->fl_nspid: %p > nspidof:%p\n", pid_ns, &init_pid_ns, > + fl->fl_nspid, ns_of_pid(fl->fl_nspid)); > + if ((pid_ns != &init_pid_ns) && fl->fl_nspid && > + (pid_ns != ns_of_pid(fl->fl_nspid))) > + return 0; > + > lock_get_status(f, fl, iter->li_pos, ""); > > list_for_each_entry(bfl, &fl->fl_block, fl_block) > -- > 2.5.0
