From: Rusty Russell <rusty@rustcorp.com.au>
To: Tejun Heo <tj@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Christoph Lameter <cl@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
travis@sgi.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
steiner@sgi.com, Hugh Dickins <hugh@veritas.com>
Subject: Re: regarding the x86_64 zero-based percpu patches
Date: Thu, 15 Jan 2009 12:17:53 +1030 [thread overview]
Message-ID: <200901151217.54989.rusty@rustcorp.com.au> (raw)
In-Reply-To: <496D6300.9070402@kernel.org>
On Wednesday 14 January 2009 14:28:56 Tejun Heo wrote:
> The main problem is that the area needs to be congruent which
> basically mandates them to be contiguous.
I want to explore this assumption a little. Logically, yes, if 50% of pages are free and we have 4096 cpus, the chance that a page is free on all CPUs is 1 in 2^4095. But maybe such systems are fine with 2M pages for per-cpu areas at boot? And can page mobility tricks help us make the odds reasonable here?
Only allowing movable pages in our expansion-of-percpu area?
Thanks,
Rusty.
next prev parent reply other threads:[~2009-01-15 3:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <49649814.4040005@kernel.org>
[not found] ` <20090107120225.GA30651@elte.hu>
2009-01-07 12:13 ` regarding the x86_64 zero-based percpu patches Tejun Heo
2009-01-10 6:46 ` Rusty Russell
2009-01-12 17:23 ` Christoph Lameter
2009-01-12 17:44 ` Eric W. Biederman
2009-01-12 19:00 ` Christoph Lameter
2009-01-13 0:33 ` Tejun Heo
2009-01-13 3:01 ` Eric W. Biederman
2009-01-13 3:14 ` Tejun Heo
2009-01-13 4:07 ` Eric W. Biederman
2009-01-14 3:58 ` Tejun Heo
2009-01-15 1:47 ` Rusty Russell [this message]
2009-01-15 1:49 ` Rusty Russell
2009-01-15 20:26 ` Christoph Lameter
2009-01-15 1:34 ` Rusty Russell
2009-01-15 13:55 ` Ingo Molnar
2009-01-15 20:27 ` Christoph Lameter
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