linux-kernel - Re: About lock-less data structure patches

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 7 Apr 2011 15:05:24 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc:	Huang Ying <ying.huang@...el.com>,
	huang ying <huang.ying.caritas@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andi Kleen <andi@...stfloor.org>,
	"lenb@...nel.org" <lenb@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: About lock-less data structure patches

On Thu, Apr 07, 2011 at 02:32:06PM -0400, Mathieu Desnoyers wrote:
> * Huang Ying (ying.huang@...el.com) wrote:
> > On 04/06/2011 09:48 AM, Mathieu Desnoyers wrote:
> > > * huang ying (huang.ying.caritas@...il.com) wrote:
> > [snip]
> > >>>>
> > >>>> OK.  I will change the comments, adding these semantics explanation.
> > >>>> The user should be warned :)
> > >>>
> > >>> Yes, that makes sense. After this generalization step, if you're ok with
> > >>> this, we could aim at moving the implementation from a stack to a queue
> > >>> and provide fifo semantic rather than lifo, so that other users (e.g.
> > >>> call_rcu in the kernel) can start benefiting from it.

Just to be clear...  Currently, call_rcu() works on a per-CPU basis,
so that it can simply disable interrupts and then do the queuing
non-atomically.

However, should it be necessary to cross-queue RCU callbacks in order
to avoid ever executing an RCU callback on a given CPU, then something
like this might become useful.

							Thanx, Paul

> > >> I think that is good to move from stack to queue.
> > >>
> > >> I will send out changed lock-less data structure patchset soon.  And
> > >> we can continue to work on the new lock-less queue at the same time.
> > > 
> > > Sounds like a very good plan! Thanks!
> > 
> > Maybe you can send out your lock-less queue patches, so we can work on that.
> 
> Yep, let's wait until your implementation is finalized and merged, and
> then ping me again so I can cook up a RFC patch turning llist into a
> queue, if it's OK with you.
> 
> Thanks,
> 
> Mathieu
> 
> > 
> > Best Regards,
> > Huang Ying
> 
> -- 
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/