linux-kernel - Re: [PATCH 20/40] autonuma: alloc/free/init mm

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]

Message-ID: <20120712180828.GL20382@redhat.com>
Date:	Thu, 12 Jul 2012 20:08:28 +0200
From:	Andrea Arcangeli <aarcange@...hat.com>
To:	Konrad Rzeszutek Wilk <konrad@...nok.org>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Hillf Danton <dhillf@...il.com>, Dan Smith <danms@...ibm.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, Paul Turner <pjt@...gle.com>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	Mike Galbraith <efault@....de>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Bharata B Rao <bharata.rao@...il.com>,
	Lee Schermerhorn <Lee.Schermerhorn@...com>,
	Rik van Riel <riel@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
	Christoph Lameter <cl@...ux.com>,
	Alex Shi <alex.shi@...el.com>,
	Mauricio Faria de Oliveira <mauricfo@...ux.vnet.ibm.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Don Morris <don.morris@...com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: Re: [PATCH 20/40] autonuma: alloc/free/init mm_autonuma

On Sat, Jun 30, 2012 at 01:12:18AM -0400, Konrad Rzeszutek Wilk wrote:
> On Thu, Jun 28, 2012 at 02:56:00PM +0200, Andrea Arcangeli wrote:
> > This is where the mm_autonuma structure is being handled. Just like
> > sched_autonuma, this is only allocated at runtime if the hardware the
> > kernel is running on has been detected as NUMA. On not NUMA hardware
> 
> I think the correct wording is "non-NUMA", not "not NUMA".

That sounds far too easy to me, but I've no idea what's the right is here.

> > the memory cost is reduced to one pointer per mm.
> > 
> > To get rid of the pointer in the each mm, the kernel can be compiled
> > with CONFIG_AUTONUMA=n.
> > 
> > Signed-off-by: Andrea Arcangeli <aarcange@...hat.com>
> > ---
> >  kernel/fork.c |    7 +++++++
> >  1 files changed, 7 insertions(+), 0 deletions(-)
> > 
> > diff --git a/kernel/fork.c b/kernel/fork.c
> > index 0adbe09..3e5a0d9 100644
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -527,6 +527,8 @@ static void mm_init_aio(struct mm_struct *mm)
> >  
> >  static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
> >  {
> > +	if (unlikely(alloc_mm_autonuma(mm)))
> > +		goto out_free_mm;
> 
> So reading that I would think that on non-NUMA machines this would fail
> (since there is nothing to allocate). But that is not the case
> (I hope!?) Perhaps just make the function not return any values?

It doesn't fail, it returns 0 on non-NUMA. It's identical to
alloc_task_autonuma, per prev email.
--
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/