From: "J. Bruce Fields" <bfields@fieldses.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nikolay Borisov <kernel@kyup.com>,
jlayton@poochiereds.net, viro@zeniv.linux.org.uk,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
containers@lists.linux-foundation.org,
serge.hallyn@canonical.com
Subject: Re: [RFC PATCH] locks: Show only file_locks created in the same pidns as current process
Date: Tue, 2 Aug 2016 13:40:03 -0400 [thread overview]
Message-ID: <20160802174003.GD11767@fieldses.org> (raw)
In-Reply-To: <87r3a7qhy0.fsf@x220.int.ebiederm.org>
On Tue, Aug 02, 2016 at 11:00:39AM -0500, Eric W. Biederman wrote:
> Nikolay Borisov <kernel@kyup.com> writes:
>
> > 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, 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.
>
> The locks always confuse me so I am not 100% connecting locks
> to a pid namespace is appropriate.
>
> That said if you are going to filter by pid namespace please use the pid
> namespace of proc, not the pid namespace of the process reading the
> file.
Oh, that makes sense, thanks.
What does /proc/mounts use, out of curiosity? The mount namespace that
/proc was originally mounted in?
--b.
>
> Different contents of files depending on who opens them is generally to
> be discouraged.
>
> Eric
>
> > Signed-off-by: Nikolay Borisov <kernel@kyup.com>
> > ---
> > 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)
next prev parent reply other threads:[~2016-08-02 17:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-02 14:42 [RFC PATCH] locks: Show only file_locks created in the same pidns as current process Nikolay Borisov
2016-08-02 14:45 ` Nikolay Borisov
2016-08-02 15:05 ` J. Bruce Fields
2016-08-02 15:20 ` Nikolay Borisov
2016-08-02 15:43 ` J. Bruce Fields
2016-08-02 16:00 ` Eric W. Biederman
2016-08-02 17:40 ` J. Bruce Fields [this message]
2016-08-02 19:09 ` Eric W. Biederman
2016-08-02 19:44 ` J. Bruce Fields
2016-08-02 20:01 ` Jeff Layton
2016-08-02 20:11 ` Nikolay Borisov
2016-08-02 20:34 ` J. Bruce Fields
2016-08-03 7:35 ` [PATCH v2] locks: Filter /proc/locks output on proc pid ns Nikolay Borisov
2016-08-03 13:46 ` Jeff Layton
2016-08-03 14:17 ` Nikolay Borisov
2016-08-03 14:28 ` J. Bruce Fields
2016-08-03 14:33 ` Nikolay Borisov
2016-08-03 14:54 ` Pavel Emelyanov
2016-08-03 15:00 ` Nikolay Borisov
2016-08-03 15:06 ` J. Bruce Fields
2016-08-03 15:10 ` Nikolay Borisov
2016-08-03 17:35 ` Eric W. Biederman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160802174003.GD11767@fieldses.org \
--to=bfields@fieldses.org \
--cc=containers@lists.linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=jlayton@poochiereds.net \
--cc=kernel@kyup.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=serge.hallyn@canonical.com \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).