From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH] Fix interrupt distribution in ppc970 From: Michael Ellerman To: mohan@in.ibm.com In-Reply-To: <20070307045341.GG7476@in.ibm.com> References: <20061208045537.GA14626@in.ibm.com> <17798.6928.378248.28903@cargo.ozlabs.ibm.com> <20061218105706.GB3911@in.ibm.com> <20070306135754.GB7476@in.ibm.com> <1173190615.4675.30.camel@concordia.ozlabs.ibm.com> <20070306165529.GD7476@in.ibm.com> <1173202634.4675.37.camel@concordia.ozlabs.ibm.com> <20070307045341.GG7476@in.ibm.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-jVM5s4y5HBCdHwnTYQ07" Date: Wed, 07 Mar 2007 11:52:32 +0100 Message-Id: <1173264752.5101.49.camel@concordia.ozlabs.ibm.com> Mime-Version: 1.0 Cc: ppcdev , Paul Mackerras , fastboot@lists.osdl.org Reply-To: michael@ellerman.id.au List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-jVM5s4y5HBCdHwnTYQ07 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Wed, 2007-03-07 at 10:23 +0530, Mohan Kumar M wrote: > On Tue, Mar 06, 2007 at 06:37:14PM +0100, Michael Ellerman wrote: > > On Tue, 2007-03-06 at 22:25 +0530, Mohan Kumar M wrote: > > > On Tue, Mar 06, 2007 at 03:16:55PM +0100, Michael Ellerman wrote: > > > > First, I don't know why we keep telling people to use maxcpus=3D1 f= or > > > > kexec/kdump - it's causing bugs, and I don't know of any that it fi= xes? > > >=20 > > > Some distros want to use maxcpus=3D1 for kdump. > >=20 > > Yeah OK. > >=20 > > > > Second, the way you've written this is not so good. The xics code s= hould > > > > not be checking that "maxcpus" exists on the command line, it shoul= d be > > > > checking that the distrib server points to a cpu that is online - u= sing > > > > cpu_online() etc. > > > > > > >=20 > > > In get_irq_server function in xics.c, "noirqdistrib" command line > > > parameter is indirectly checked for routing the interrupts either to = a > > > specific cpu or to all cpus. So I think checking for maxcpus=3D comma= nd > > > line parameter in xics.c is not a problem. > >=20 > > No, it checks a flag, it doesn't run strstr on the saved command line. > > > What if I use a flag (or existing global variable if any) to check for > the presence of maxcpus kernel paramter? There's already maxcpus in init/main.c, that would probably be better, though still ugly. > > > Also during the xics_init_IRQ function other cpus (secondary cpus) wi= ll > > > not be online, they are made online at a later stage. So using > > > cpu_online() function at xics_init_IRQ will return true only for boot > > > cpu id. > >=20 > > OK, so you should be able to use cpus possible map or something similar= . > > > Hmm, I think cpus possible map will have an entry for the offline cpu > also. You're right, it will, did I mention that maxcpus=3D is broken :) cheers --=20 Michael Ellerman OzLabs, IBM Australia Development Lab wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183) We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person --=-jVM5s4y5HBCdHwnTYQ07 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (GNU/Linux) iD8DBQBF7plwdSjSd0sB4dIRAhidAJ0fodEx0rXo4T1k2gKC1Np2GAQT5wCfUPqi VTDIlnQmlXZhP4vqEZ4kNYw= =4r62 -----END PGP SIGNATURE----- --=-jVM5s4y5HBCdHwnTYQ07--