From: Eric Dumazet <dada1@cosmosbay.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: minyard@acm.org, Linux Kernel <linux-kernel@vger.kernel.org>,
netdev@vger.kernel.org, shemminger@vyatta.com,
paulmck@linux.vnet.ibm.com
Subject: Re: [PATCH 3/3] Convert the UDP hash lock to RCU
Date: Tue, 07 Oct 2008 11:24:51 +0200 [thread overview]
Message-ID: <48EB2AE3.3080200@cosmosbay.com> (raw)
In-Reply-To: <1223367480.26330.7.camel@lappy.programming.kicks-ass.net>
Peter Zijlstra a écrit :
> On Mon, 2008-10-06 at 23:22 +0200, Eric Dumazet wrote:
>
>> Or just add SLAB_DESTROY_BY_RCU to slab creation in proto_register()
>> for "struct proto udp_prot/udpv6_prot" so that kmem_cache_free()
>> done in sk_prot_free() can defer freeing to RCU...
>
> Be careful!, SLAB_DESTROY_BY_RCU just means the slab page gets
> RCU-freed, this means that slab object pointers stay pointing to valid
> memory, but it does _NOT_ mean those slab objects themselves remain
> valid.
>
> The slab allocator is free to re-use those objects at any time -
> irrespective of the rcu-grace period. Therefore you will have to be able
> to validate that the object you point to is indeed the object you
> expect, otherwise strange and wonderful things will happen.
>
Thanks for this clarification. I guess we really need a rcu head then :)
next prev parent reply other threads:[~2008-10-07 9:25 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-06 18:50 [PATCH 3/3] Convert the UDP hash lock to RCU Corey Minyard
2008-10-06 21:22 ` Eric Dumazet
2008-10-06 21:40 ` David Miller
2008-10-06 23:08 ` Corey Minyard
2008-10-07 8:37 ` Evgeniy Polyakov
2008-10-07 14:16 ` Christoph Lameter
2008-10-07 14:29 ` Evgeniy Polyakov
2008-10-07 14:38 ` Christoph Lameter
2008-10-07 14:33 ` Paul E. McKenney
2008-10-07 14:45 ` Christoph Lameter
2008-10-07 15:07 ` Eric Dumazet
2008-10-07 15:07 ` Paul E. McKenney
2008-10-07 5:24 ` Eric Dumazet
2008-10-07 8:54 ` Benny Amorsen
2008-10-07 12:59 ` Eric Dumazet
2008-10-07 14:07 ` Stephen Hemminger
2008-10-07 20:55 ` David Miller
2008-10-07 21:20 ` Stephen Hemminger
2008-10-08 13:55 ` Eric Dumazet
2008-10-08 18:45 ` David Miller
2008-10-07 16:43 ` Corey Minyard
2008-10-07 18:26 ` David Miller
2008-10-08 8:35 ` Eric Dumazet
2008-10-08 16:38 ` David Miller
2008-10-07 8:31 ` Peter Zijlstra
2008-10-07 14:36 ` Paul E. McKenney
2008-10-07 18:29 ` David Miller
2008-10-06 22:07 ` Corey Minyard
2008-10-07 8:17 ` Peter Zijlstra
2008-10-07 9:24 ` Eric Dumazet [this message]
2008-10-07 14:15 ` Christoph Lameter
2008-10-07 14:38 ` Paul E. McKenney
2008-10-07 14:50 ` Eric Dumazet
2008-10-07 15:05 ` Paul E. McKenney
2008-10-07 15:09 ` Peter Zijlstra
2008-10-07 15:23 ` Christoph Lameter
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=48EB2AE3.3080200@cosmosbay.com \
--to=dada1@cosmosbay.com \
--cc=a.p.zijlstra@chello.nl \
--cc=linux-kernel@vger.kernel.org \
--cc=minyard@acm.org \
--cc=netdev@vger.kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=shemminger@vyatta.com \
/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).