[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <200901151217.54989.rusty@rustcorp.com.au>
Date: Thu, 15 Jan 2009 12:17:53 +1030
From: Rusty Russell <rusty@...tcorp.com.au>
To: Tejun Heo <tj@...nel.org>
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>,
Christoph Lameter <cl@...ux-foundation.org>,
Ingo Molnar <mingo@...e.hu>, travis@....com,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Andrew Morton <akpm@...ux-foundation.org>, steiner@....com,
Hugh Dickins <hugh@...itas.com>
Subject: Re: regarding the x86_64 zero-based percpu patches
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.
--
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/
Powered by blists - more mailing lists