From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C550C31E49 for ; Wed, 19 Jun 2019 13:57:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D53FE205ED for ; Wed, 19 Jun 2019 13:57:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729655AbfFSN5W (ORCPT ); Wed, 19 Jun 2019 09:57:22 -0400 Received: from shelob.surriel.com ([96.67.55.147]:56634 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726047AbfFSN5W (ORCPT ); Wed, 19 Jun 2019 09:57:22 -0400 Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92) (envelope-from ) id 1hdb5P-0001OE-GR; Wed, 19 Jun 2019 09:57:15 -0400 Message-ID: Subject: Re: [PATCH 1/8] sched: introduce task_se_h_load helper From: Rik van Riel To: Dietmar Eggemann , peterz@infradead.org Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, kernel-team@fb.com, morten.rasmussen@arm.com, tglx@linutronix.de, dietmar.eggeman@arm.com, mgorman@techsingularity.com, vincent.guittot@linaro.org Date: Wed, 19 Jun 2019 09:57:14 -0400 In-Reply-To: <55d914d2-fba2-48c0-e7ff-3c7337c8cf8e@arm.com> References: <20190612193227.993-1-riel@surriel.com> <20190612193227.993-2-riel@surriel.com> <55d914d2-fba2-48c0-e7ff-3c7337c8cf8e@arm.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-oEUOPJ5dbVg088eTgini" User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-oEUOPJ5dbVg088eTgini Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2019-06-19 at 14:52 +0200, Dietmar Eggemann wrote: > > @@ -7833,14 +7834,19 @@ static void update_cfs_rq_h_load(struct > > cfs_rq *cfs_rq) > > } > > } > > =20 > > -static unsigned long task_h_load(struct task_struct *p) > > +static unsigned long task_se_h_load(struct sched_entity *se) > > { > > - struct cfs_rq *cfs_rq =3D task_cfs_rq(p); > > + struct cfs_rq *cfs_rq =3D cfs_rq_of(se); > > =20 > > update_cfs_rq_h_load(cfs_rq); > > - return div64_ul(p->se.avg.load_avg * cfs_rq->h_load, > > + return div64_ul(se->avg.load_avg * cfs_rq->h_load, > > cfs_rq_load_avg(cfs_rq) + 1); > > } >=20 > I wonder if this is necessary. I placed a BUG_ON(!entity_is_task(se)) > into task_se_h_load() after I applied the whole patch-set and ran > some > taskgroup related testcases. It didn't hit. >=20 > So why not use task_h_load(task_of(se)) instead? >=20 > [...] That would work, but task_h_load then dereferences task->se to get the se->avg.load_avg value. Going back to task from the se, only to then get the se from the task seems a little unnecessary :) Can you explain why you think task_h_load(task_of(se)) would be better? I think I may be overlooking something. --=20 All Rights Reversed. --=-oEUOPJ5dbVg088eTgini Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAl0KPzsACgkQznnekoTE 3oPx1ggAjy93qmakRLrYS2CAJyHGDnZX81xCQXR5YGmPKVmQ85rNmNBNAapP5FHC UgRLZmPB1b8bA3gze3yiWeY/s6LLwvIa+LVXbxnhCnsWxATyRsbPOmtgcf1fpJ9+ rcWSAtCUxIMWUQcxcxHcHIyGdkaMfU0TYg45vB6D02tRuCMv+pRbzYNtEt05GWDH iUlm7OtMlWaII43pad7U74QBsHr+2NCnsGxaf6e+9YL8lLDtxDfN4HJaN3qyomhD Qawcf1ob6itUfqEbZ5HZZdQq2ha4D7cKplwwq88S0cqhN4Ow/rCLHnKkTFPUtfE0 avSSxATac/ldps74Pmd6dXTJY1WUew== =gXED -----END PGP SIGNATURE----- --=-oEUOPJ5dbVg088eTgini--