Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751732AbZIWNtI (ORCPT ); Wed, 23 Sep 2009 09:49:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751615AbZIWNtH (ORCPT ); Wed, 23 Sep 2009 09:49:07 -0400 Received: from smtp2.ultrahosting.com ([74.213.174.253]:48928 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751541AbZIWNtG (ORCPT ); Wed, 23 Sep 2009 09:49:06 -0400 Date: Wed, 23 Sep 2009 09:44:33 -0400 (EDT) From: Christoph Lameter X-X-Sender: cl@V090114053VZO-1 To: Tejun Heo cc: Nick Piggin , Tony Luck , Fenghua Yu , linux-ia64 , Ingo Molnar , Rusty Russell , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus In-Reply-To: <4AB983B6.6050203@kernel.org> Message-ID: References: <1253605214-23210-1-git-send-email-tj@kernel.org> <1253605214-23210-3-git-send-email-tj@kernel.org> <4AB983B6.6050203@kernel.org> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1080 Lines: 24 On Wed, 23 Sep 2009, Tejun Heo wrote: > On ia64, the first chunk is fixed at PERCPU_PAGE_SIZE. It's something > hardwired into the page fault logic and the linker script. Build will > fail if the static + reserved area goes over PERCPU_PAGE_SIZE and in > that case ia64 will need to update the special case page fault logic > and increase PERCPU_PAGE_SIZE. The area reserved above is interim > per-cpu area for cpu0 which is used between head.S and proper percpu > area setup and will be ditched once initialization is complete. You did not answer my question. The local percpu variables are accessed via a static per cpu virtual mapping. You cannot place per cpu variables outside of that virtual address range of PERCPU_PAGE_SIZE. What happens if the percpu allocator allocates more data than available in the reserved area? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/