From: Thomas Graf <tgraf@suug.ch>
To: Cong Wang <cwang@twopensource.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
"David S. Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: mmap()ed AF_NETLINK: lockdep and sleep-in-atomic warnings
Date: Tue, 14 Jul 2015 11:38:25 +0200 [thread overview]
Message-ID: <20150714093825.GC20597@pox.localdomain> (raw)
In-Reply-To: <CAHA+R7OPHFjL83RKkTmso3s25_f7TKA=HhFKU_yOnRhsn1WxQg@mail.gmail.com>
On 07/13/15 at 10:11pm, Cong Wang wrote:
> Caused by:
>
> commit 21e4902aea80ef35afc00ee8d2abdea4f519b7f7
> Author: Thomas Graf <tgraf@suug.ch>
> Date: Fri Jan 2 23:00:22 2015 +0100
>
> netlink: Lockless lookup with RCU grace period in socket release
>
> Defers the release of the socket reference using call_rcu() to
> allow using an RCU read-side protected call to rhashtable_lookup()
>
> This restores behaviour and performance gains as previously
> introduced by e341694 ("netlink: Convert netlink_lookup() to use
> RCU protected hash table") without the side effect of severely
> delayed socket destruction.
>
> Signed-off-by: Thomas Graf <tgraf@suug.ch>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
>
> We can't hold mutex lock in a rcu callback, perhaps we could
> defer the mmap ring cleanup to a workqueue.
The socket should be dead at this point. It might be simpler to
add a netlink_release_ring() function which doesn't require
locking at all. It would also get rid of all the special handling
for closing vs. non-closing.
next prev parent reply other threads:[~2015-07-14 9:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-13 13:18 mmap()ed AF_NETLINK: lockdep and sleep-in-atomic warnings Kirill A. Shutemov
2015-07-14 5:11 ` Cong Wang
2015-07-14 9:38 ` Thomas Graf [this message]
2015-07-14 9:50 ` Florian Westphal
2015-07-14 18:40 ` Stephen Hemminger
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=20150714093825.GC20597@pox.localdomain \
--to=tgraf@suug.ch \
--cc=cwang@twopensource.com \
--cc=davem@davemloft.net \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.