From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH 6/6] powerpc: Enable sparse irq_descs on powerpc From: Michael Ellerman To: Grant Likely In-Reply-To: References: <91cec5c64da4ca31a025fc7c45d9f1b93c8b98da.1255499081.git.michael@ellerman.id.au> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-FCoKYUK7LrGZ9aySGy+f" Date: Thu, 15 Oct 2009 10:51:16 +1100 Message-Id: <1255564276.9651.14.camel@concordia> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.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: , --=-FCoKYUK7LrGZ9aySGy+f Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Wed, 2009-10-14 at 12:44 -0600, Grant Likely wrote: > On Tue, Oct 13, 2009 at 11:45 PM, Michael Ellerman > wrote: > > Defining CONFIG_SPARSE_IRQ enables generic code that gets rid of the > > static irq_desc array, and replaces it with an array of pointers to > > irq_descs. > > > > It also allows node local allocation of irq_descs, however we > > currently don't have the information available to do that, so we just > > allocate them on all on node 0. > > > > Signed-off-by: Michael Ellerman >=20 > Why not make sparse IRQs manditory for all platforms? Is there a > performance concern with doing so? From a maintenance perspective, > I'd rather see IRQ descs manged in one way only to keep the code > simple. I agree on the maintenance angle. My thinking was we'd run with it optional but default y for a release or two, and if no one complains we can make it mandatory. It does make some code paths bigger, and looking up an irq_desc is going to take slightly more cycles. I don't think it's a big issue, but I thought we should try it for a while before making it mandatory. The code has only been tested on x86 and sh as far as I know. cheers ps. thanks for the review --=-FCoKYUK7LrGZ9aySGy+f Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEABECAAYFAkrWY/QACgkQdSjSd0sB4dJXaQCfWc5lnHMwbG2TDY+c2d3KL6hP TPgAnAxAtNrs/d1wd1CKnvtBX5n9p+XN =ySgu -----END PGP SIGNATURE----- --=-FCoKYUK7LrGZ9aySGy+f--