linux-kernel - Re: [rfc][patch] x86-64 new smp_call

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

Date:	Wed, 27 Feb 2008 14:50:41 +0100
From:	Nick Piggin <npiggin@...e.de>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Andi Kleen <ak@...e.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-arch@...r.kernel.org
Subject: Re: [rfc][patch] x86-64 new smp_call_function design

On Wed, Feb 27, 2008 at 02:27:13PM +0100, Ingo Molnar wrote:
> 
> * Nick Piggin <npiggin@...e.de> wrote:
> 
> > This isn't finished yet, however I'd just like to ask for comments.
> 
> looks really interesting!
> 
> only one fundamental observation:
> 
> > +struct call_data {
> > +	spinlock_t lock;
> > +	struct list_head list;
> >  	void (*func) (void *info);
> >  	void *info;
> > +	unsigned int flags;
> > +	unsigned int refs;
> > +	cpumask_t cpumask;
> > +	struct rcu_head rcu_head;
> >  };
> 
> > +struct call_single_data {
> > +	struct list_head list;
> > +	void (*func) (void *info);
> > +	void *info;
> > +	unsigned int flags;
> > +};
> 
> the two structures are quite similar in size and role - why not have a 
> type field and handle them largely together? I think we should try to 
> preserve a single queue and a single vector - that would remove a number 
> of ugly special-cases from the patch.

A single queue will kill one of the big fundamental scalability
improvements of the call_single. That's the problem.

--
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/