From: Omar Sandoval <osandov@osandov.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Alexey Dobriyan <adobriyan@gmail.com>,
Eric Biederman <ebiederm@xmission.com>,
James Morse <james.morse@arm.com>,
Bhupesh Sharma <bhsharma@redhat.com>,
kernel-team@fb.com
Subject: Re: [PATCH v2 2/7] proc/kcore: replace kclist_lock rwlock with rwsem
Date: Tue, 17 Jul 2018 20:24:05 -0700 [thread overview]
Message-ID: <20180718032405.GB29351@vader> (raw)
In-Reply-To: <20180717193841.271d1c57b6f88d75c83892be@linux-foundation.org>
On Tue, Jul 17, 2018 at 07:38:41PM -0700, Andrew Morton wrote:
> On Thu, 12 Jul 2018 17:09:34 -0700 Omar Sandoval <osandov@osandov.com> wrote:
>
> > From: Omar Sandoval <osandov@fb.com>
> >
> > Now we only need kclist_lock from user context and at fs init time, and
> > the following changes need to sleep while holding the kclist_lock.
> >
> > ...
> >
> > --- a/fs/proc/kcore.c
> > +++ b/fs/proc/kcore.c
> > @@ -59,8 +59,8 @@ struct memelfnote
> > };
> >
> > static LIST_HEAD(kclist_head);
> > -static DEFINE_RWLOCK(kclist_lock);
> > -static int kcore_need_update = 1;
> > +static DECLARE_RWSEM(kclist_lock);
> > +static atomic_t kcore_need_update = ATOMIC_INIT(1);
>
> It's unclear why kcore_need_update was changed to atomic_t - it's still
> updated under kclist_lock?
Not in the hotplug notifier (kcore_callback()) anymore, so I need the
atomic_cmpxchg() in __kcore_update_ram(). That could use a mention in
the commit message.
> Maybe it's for a later patch.
>
>
next prev parent reply other threads:[~2018-07-18 3:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 0:09 [PATCH v2 0/7] /proc/kcore improvements Omar Sandoval
2018-07-13 0:09 ` [PATCH v2 1/7] proc/kcore: don't grab lock for kclist_add() Omar Sandoval
2018-07-18 2:35 ` Andrew Morton
2018-07-18 3:19 ` Omar Sandoval
2018-07-13 0:09 ` [PATCH v2 2/7] proc/kcore: replace kclist_lock rwlock with rwsem Omar Sandoval
2018-07-18 2:38 ` Andrew Morton
2018-07-18 3:24 ` Omar Sandoval [this message]
2018-07-18 3:27 ` Andrew Morton
2018-07-18 3:36 ` Omar Sandoval
2018-07-13 0:09 ` [PATCH v2 3/7] proc/kcore: fix memory hotplug vs multiple opens race Omar Sandoval
2018-07-13 0:09 ` [PATCH v2 4/7] proc/kcore: hold lock during read Omar Sandoval
2018-07-13 0:09 ` [PATCH v2 5/7] proc/kcore: clean up ELF header generation Omar Sandoval
2018-07-13 0:09 ` [PATCH v2 6/7] proc/kcore: optimize multiple page reads Omar Sandoval
2018-07-13 0:09 ` [PATCH v2 7/7] proc/kcore: add vmcoreinfo note to /proc/kcore Omar Sandoval
2018-07-18 2:44 ` Andrew Morton
2018-07-18 3:27 ` Omar Sandoval
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=20180718032405.GB29351@vader \
--to=osandov@osandov.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=bhsharma@redhat.com \
--cc=ebiederm@xmission.com \
--cc=james.morse@arm.com \
--cc=kernel-team@fb.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/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).