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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B869EC43334 for ; Tue, 19 Jul 2022 14:30:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235932AbiGSOaC (ORCPT ); Tue, 19 Jul 2022 10:30:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239546AbiGSO3g (ORCPT ); Tue, 19 Jul 2022 10:29:36 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BD125FACE; Tue, 19 Jul 2022 07:17:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658240241; x=1689776241; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=6PAXqYH/NtVLRyLe2sv7ux6nLdISex8fMwmJ79lrbUo=; b=nncN1c8oYkRD3wkpyhekzipqYeQ7eh1QmHx5hlbIzDm/m/XjhWp+bQdX tPwwIcGyzMl+JPadr6F9V+85G7NxEJbJ3fLE8hyldMARuGNY5EnuyYEO4 E30hISSnK5MOI3C1k3H2YwjthTFPyXoOqMJMigkVgPp4AMFTgdm2JQ+OJ YOUi+RzTfSQ3XHWACwb5F6bSipUS95hMv8idGvTIJG0ZCBv1904UMkxYC TR7NR0IJqTLUdLe5k8iFb7Rx0e1uapj+PPCY5GxgA1p7eH3yigjx69pqX 1Uf7HNBqBQBBiKhqoyceAL/4X84W92cJ4Jjdtsfy1HqIdty87L+XD2yfs Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10412"; a="287247085" X-IronPort-AV: E=Sophos;i="5.92,284,1650956400"; d="scan'208";a="287247085" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jul 2022 07:17:21 -0700 X-IronPort-AV: E=Sophos;i="5.92,284,1650956400"; d="scan'208";a="630344929" Received: from dukechan-mobl.gar.corp.intel.com ([10.215.250.179]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jul 2022 07:17:17 -0700 Message-ID: Subject: Re: [PATCH v3 3/4] thermal/core: Build ascending ordered indexes for the trip points From: Zhang Rui To: Daniel Lezcano , rafael@kernel.org Cc: quic_manafm@quicinc.com, amitk@kernel.org, lukasz.luba@arm.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 19 Jul 2022 22:17:20 +0800 In-Reply-To: References: <20220715210911.714479-1-daniel.lezcano@linaro.org> <20220715210911.714479-3-daniel.lezcano@linaro.org> <6d08939a167870ff7c1c83bb254fda5939f1d648.camel@intel.com> <04bd27a8-5148-c8eb-5687-83ef511618df@linaro.org> <7ee301b76beb679f89e946dfb5921a2d853bd8dc.camel@intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.1-0ubuntu1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Tue, 2022-07-19 at 09:22 +0200, Daniel Lezcano wrote: > On 19/07/2022 03:14, Zhang Rui wrote: > > On Mon, 2022-07-18 at 15:21 +0200, Daniel Lezcano wrote: > > >=20 > > > Hi Zhang, > > >=20 > > > thanks for the review > > >=20 > > > On 18/07/2022 07:28, Zhang Rui wrote: > > > > On Fri, 2022-07-15 at 23:09 +0200, Daniel Lezcano wrote: > > >=20 > > > [ ... ] > > >=20 > > > > > Instead of taking the risk of breaking the existing > > > > > platforms, > > > > > use an > > > > > array of temperature ordered trip identifiers and make it > > > > > available > > > > > for the code needing to browse the trip points in an ordered > > > > > way. > > > > >=20 > > > > > Signed-off-by: Daniel Lezcano > > > > > --- > > >=20 > > > [ ... ] > > >=20 > > > > > +static void sort_trips_indexes(struct thermal_zone_device > > > > > *tz) > > > > > +{ > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0int i, j; > > > > > + > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0for (i =3D 0; i < tz->= trips; i++) > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0tz->trips_indexes[i] =3D i; > > > > > + > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0for (i =3D 0; i < tz->= trips; i++) { > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0for (j =3D i + 1; j < tz->trips; j++) { > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= int t1, t2; > > > > > + > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= tz->ops->get_trip_temp(tz, tz- > > > > > > trips_indexes[i], &t1); > > > >=20 > > > > This line can be moved to the upper loop. > > >=20 > > > Right, thanks! > > >=20 > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= tz->ops->get_trip_temp(tz, tz- > > > > > > trips_indexes[j], &t2); > > > > > + > > > >=20 > > > > what about the disabled trip points? > > > >=20 > > > > we should ignore those trip points and check the return value > > > > to > > > > make > > > > sure we're comparing the valid trip_temp values. > > >=20 > > > We don't have to care about, whatever the position, the > > > corresponding > > > trip id will be disabled by the trip init function before calling > > > this > > > one and ignored in the handle_thermal_trip() function > >=20 > > hah, I missed this one and replied to your latest reply directly. > >=20 > > The thing I'm concerning is that=C2=A0if we don't check the return > > value, > > for a disabled trip point, the trip_temp (t1/t2) returned is some > > random value, it all depends on the previous value set by last > > successful .get_trip_temp(), and this may screw up the sorting. >=20 > The indexes array is the same size as the trip array, that makes the=20 > code much less prone to errors. >=20 > To have the same number of trip points, the index of the disabled > trip=20 > must be inserted also in the array. We don't care about its position > in=20 > the indexes array because it is discarded in the handle_trip_point()=20 > function anyway. For this reason, the random temperature of the > disabled=20 > trip point and the resulting position in the sorting is harmless. >=20 > It is made on purpose to ignore the return value, so we have a > simpler code. >=20 Let's take below case for example, say, we have three trip points 0, 1, 2, and trip point 1 is broken and disabled. trip temp for trip point 0 is 10 and for trip point 2 is 20. .get_trip_temp(tz, 1, &t) fails, and t is an uninitialized random value Initial: trip_indexes[0]=3D0,trip_indexes[1]=3D1,trip_indexes[2]=3D2 step1: i=3D0,j=3D1 get trip temp for trip point trip_indexes[0]=3D0 and trip_indexes[1]=3D1 trip point 1 returns trip temp 5, and it swaps with trip point 0 so trip_indexes[0]=3D1,trip_indexes[1]=3D0,trip_indexes[2]=3D2 step2: i=3D0,j=3D2 get trip temp for trip point trip_indexes[0]=3D1 and trip_indexes[2]=3D2 trip point 1 returns trip temp 25, and it swaps with trip point 2 so trip_indexes[0]=3D2,trip_indexes[1]=3D0,trip_indexes[2]=3D1 And the sorting is broken now. please correct me if I'm missing anything. thanks, rui