From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from terminus.zytor.com ([198.137.202.10]) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1M2TOi-0003k5-It for kexec@lists.infradead.org; Fri, 08 May 2009 16:58:15 +0000 Message-ID: <4A0463D1.9090800@zytor.com> Date: Fri, 08 May 2009 09:54:41 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH 01/14] x86, boot: align the .bss section in the decompressor References: <1241735222-6640-1-git-send-email-hpa@linux.intel.com> <1241735222-6640-2-git-send-email-hpa@linux.intel.com> <20090508071759.GA12808@uranus.ravnborg.org> In-Reply-To: <20090508071759.GA12808@uranus.ravnborg.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Sam Ravnborg Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, hbabu@us.ibm.com, ebiederm@xmission.com, ying.huang@intel.com, mingo@elte.hu, "H. Peter Anvin" , tglx@linutronix.de, vgoyal@redhat.com Sam Ravnborg wrote: >> } >> + . = ALIGN(32); > > Where does this magic 32 comes from? > I would assume the better choice would be: > . = ALIGN(L1_CACHE_BYTES); > > So we match the relevant CPU. > > In general for alignmnet of output sections I see the need for: > 1) Function call > 2) L1_CACHE_BYTES > 3) PAGE_SIZE > 4) 2*PAGE_SIZE > > But I see magic constant used here and there that does not match > the above (when looking at all archs). > So I act when I see a new 'magic' number.. > I picked 32 as being larger than the maximum known size that affects rep performance, but L1_CACHE_BYTES really would make more sense, you're right. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec