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From: Andi Kleen <andi@firstfloor.org>
To: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Andi Kleen <andi@firstfloor.org>, Yinghai Lu <yinghai@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"ananth@in.ibm.com" <ananth@in.ibm.com>,
	Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -v2 5/5] x86: use dmi check to treat disabled cpus as hotplug cpus.
Date: Thu, 14 Jan 2010 10:25:15 +0100	[thread overview]
Message-ID: <20100114092515.GG12241@basil.fritz.box> (raw)
In-Reply-To: <1263422958.2865.107.camel@sbs-t61.sc.intel.com>

On Wed, Jan 13, 2010 at 02:49:18PM -0800, Suresh Siddha wrote:
> On Wed, 2010-01-13 at 14:36 -0800, H. Peter Anvin wrote:
> > On 01/13/2010 02:29 PM, Suresh Siddha wrote:
> > >>
> > >> Well, that *is* working around broken code, in this case the broken code
> > >> is the percpu allocation strategy.
> > > 
> > > Andi, Recently percpu folks changed the per-cpu static first chunk to
> > > PMD SIZE right. I think that is what causing all this issue.
> > > 
> > 
> > Please don't tell me we're allocating 2 MB per CPU and throwing away
> > most of it...
> 
> Looking at the percpu code, they do seem to free the unused memory in
> that hole.

I took a look at alloc_percpu() at least and it seems to always
allocate for all possible cpus.

Unfortunately we don't have a nice accounting mechanism for it in /proc,
perhaps we should. So it's unclear right now if that is a problem or not.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

  parent reply	other threads:[~2010-01-14  9:25 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-12 23:17 [PATCH 0/5] clean up logical flat apic mode using Yinghai Lu
2010-01-12 23:17 ` [PATCH -v2 1/5] use nr_cpus= to set nr_cpu_ids early Yinghai Lu
2010-01-12 23:17 ` [PATCH 2/5] x86: using logical flat for amd cpu too Yinghai Lu
2010-01-12 23:17 ` [PATCH -v2 3/5] x86: according to nr_cpu_ids to decide if need to leave logical flat Yinghai Lu
2010-01-12 23:17 ` [PATCH -v2 5/5] x86: use dmi check to treat disabled cpus as hotplug cpus Yinghai Lu
2010-01-12 23:56   ` Suresh Siddha
2010-01-13  0:05     ` Yinghai Lu
2010-01-13  1:48       ` Suresh Siddha
2010-01-13  1:55         ` Yinghai Lu
2010-01-13  2:06           ` Suresh Siddha
2010-01-13  2:13             ` Yinghai Lu
2010-01-13  2:21               ` Suresh Siddha
2010-01-13  2:26                 ` Yinghai Lu
2010-01-13 21:46       ` Andi Kleen
2010-01-13 22:00         ` H. Peter Anvin
2010-01-13 22:23           ` Andi Kleen
2010-01-13 22:27             ` H. Peter Anvin
2010-01-13 22:29               ` Suresh Siddha
2010-01-13 22:36                 ` H. Peter Anvin
2010-01-13 22:49                   ` Suresh Siddha
2010-01-13 23:02                     ` Yinghai Lu
2010-01-13 23:13                       ` H. Peter Anvin
2010-01-13 23:52                         ` Andi Kleen
2010-01-14  9:25                     ` Andi Kleen [this message]
2010-01-12 23:17 ` [PATCH 4/5] x86: make 32bit apic flat to physflat switch like 64bit Yinghai Lu

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