From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH] x86/numa: Adjust datatypes for node and pxm Date: Mon, 23 Feb 2015 09:42:41 -0500 Message-ID: <54EB3C61.1060606@oracle.com> References: <1424542459-2615-1-git-send-email-boris.ostrovsky@oracle.com> <54EB07B10200007800062614@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <54EB07B10200007800062614@mail.emea.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: kevin.tian@intel.com, keir@xen.org, ian.campbell@citrix.com, Andrew.Cooper3@citrix.com, dario.faggioli@citrix.com, tim@xen.org, xen-devel@lists.xen.org, stefano.stabellini@citrix.com, yang.z.zhang@intel.com List-Id: xen-devel@lists.xenproject.org On 02/23/2015 04:57 AM, Jan Beulich wrote: >>>> On 21.02.15 at 19:14, wrote: >> Use u8-sized node IDs and unsigned PXMs consistently throughout >> code (and introduce nodeid_t type). >> >> Signed-off-by: Boris Ostrovsky > I think the description should call out areas not covered, like the > node encoding in the top bits of MEMF_*. > >> --- a/xen/arch/x86/srat.c >> +++ b/xen/arch/x86/srat.c >> @@ -21,44 +21,55 @@ >> #include >> #include >> >> +#define MAX_PXM 255 > Perhaps better (MAX_NUMNODES - 1) than a literal number? Or > even do away with it altogether, use MAX_NUMNODES - 1 in the > array definition and ARRAY_SIZE() elsewhere? I am not sure we can do this: PXMs are not guaranteed to be zero-based. And, in fact, the way we map PXMs to nodes is not quite right because of this --- it just so happens that PXMs are usually under 255 (and zero-based) and we can use them as index to 255-sized array. IIRC the spec defines them as 32-bit values. -boris