From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 30 Mar 2008 16:03:56 -0500 From: Jack Steiner Subject: Re: [RFC 8/8] x86_64: Support for new UV apic Message-ID: <20080330210356.GA13383@sgi.com> References: <20080324182122.GA28327@sgi.com> <87abknhzhd.fsf@basil.nowhere.org> <20080325175657.GA6262@sgi.com> <20080326073823.GD3442@elte.hu> <86802c440803301323q5c4bd4f4k1f9bdc1d6b1a0a7b@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86802c440803301323q5c4bd4f4k1f9bdc1d6b1a0a7b@mail.gmail.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Yinghai Lu Cc: Ingo Molnar , Andi Kleen , tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Sun, Mar 30, 2008 at 01:23:12PM -0700, Yinghai Lu wrote: > On Wed, Mar 26, 2008 at 12:38 AM, Ingo Molnar wrote: > > > > * Jack Steiner wrote: > > > > > > > - obj-y += genapic_64.o genapic_flat_64.o > > > > > + obj-y += genapic_64.o genapic_flat_64.o genx2apic_uv_x.o > > > > > > > > Definitely should be a CONFIG > > > > > > Not sure that I understand why. The overhead of UV is minimal & we > > > want UV enabled in all distro kernels. OTOH, small embedded systems > > > probably want to eliminate every last bit of unneeded code. > > > > > > Might make sense to have a config option. Thoughts???? > > > > i wouldnt mind having UV enabled by default (it can be a config option > > but default-enabled on generic kernels so all distros will pick this hw > > support up), but we definitely need the genapic unification before we > > can add more features. > > config option would be reasonable. > for x86_64 > subarch already have X86_PC, X86_VSMP. > we have X86_UVSMP If there was a significant differece between UV and generic kernels (or hardware), then I would agree. However, the only significant difference is the APIC model on large systems. Small systems are exactly compatible. The problem with subarch is that we want 1 binary kernel to support both generic hardware AND uv hardware. This restriction is desirable for the distros and software vendors. Otherwise, additional kernel images would have to be built, released, & certified. --- jack -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org