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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 4595DC4BA24 for ; Wed, 26 Feb 2020 22:43:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1848620658 for ; Wed, 26 Feb 2020 22:43:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="G4kRN/gb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727815AbgBZWn0 (ORCPT ); Wed, 26 Feb 2020 17:43:26 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:43491 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727822AbgBZWn0 (ORCPT ); Wed, 26 Feb 2020 17:43:26 -0500 Received: by mail-pl1-f193.google.com with SMTP id p11so273088plq.10 for ; Wed, 26 Feb 2020 14:43:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:content-transfer-encoding:in-reply-to:references :subject:from:cc:to:date:message-id:user-agent; bh=tmmzbig6kKd2J1vSLS/3+Ly3DK1KMOkPEr7ocA5n8BU=; b=G4kRN/gblOwhZ9Ydgqv7ZiG7wbtZIxzqLwbWe4wGx7O3kdMCtDPX8HYO7WSz9jaYG6 qRDSPJTqBduvJZ5hNUCW9fZ4YUI1AwZd/VN4tmk6kvh3t1vDDgi8WIXh1Na0DTBy+IoV /gLLKqvaHocsv0u8y+Q+IwrIQb/27Gw2n6sy4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:content-transfer-encoding :in-reply-to:references:subject:from:cc:to:date:message-id :user-agent; bh=tmmzbig6kKd2J1vSLS/3+Ly3DK1KMOkPEr7ocA5n8BU=; b=k4UQkW77WUhgtyo0fZKYuMaO629gXeGiVwLayfpSlj8MRAgXN5UJjEyAf+ynF/0Hx+ VzJo1QoacshvkAEOYmhRxfjobfRG7RzZpwj2oebVw4rf5U5hOVAp30NOOK+OXdyzP7X6 qeaZ6Qj63bB6yJqNYxJIOpMOOJY8s2ul7Nw6yp6qf3yqJJFnyQqv3h6PqXz+GgV2DqtT J7SawqfXXAN/0ha1L86f29S2KeErO4+lFAAyDuuX+jZOpwK6QPsweC1F6PvqMRBOasNt D4hysSM8wqDmy/fbUtLl/9EkWmd6d2wHT53pTrAK/vqScN2mXyEv3e4OJ6aOeJLPg1Et 7Ncw== X-Gm-Message-State: APjAAAXGwubZaSFAYD9elHM0SK2R8aI9+YHB9cCvxLb9clmbYujVpS+A brh90UeqzEHnJ4Nsw0EmxLHs2A== X-Google-Smtp-Source: APXvYqyU28YSEFboz9xxQdDdc2W7O/rwUruv/UskcxB861z9ZN4/Qcv4sP2DfN01S+LwztHf98W1Hw== X-Received: by 2002:a17:902:8d94:: with SMTP id v20mr1565171plo.259.1582757005506; Wed, 26 Feb 2020 14:43:25 -0800 (PST) Received: from chromium.org ([2620:15c:202:1:fa53:7765:582b:82b9]) by smtp.gmail.com with ESMTPSA id v8sm3944025pgt.52.2020.02.26.14.43.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Feb 2020 14:43:24 -0800 (PST) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: <1582694833-9407-3-git-send-email-mkshah@codeaurora.org> References: <1582694833-9407-1-git-send-email-mkshah@codeaurora.org> <1582694833-9407-3-git-send-email-mkshah@codeaurora.org> Subject: Re: [PATCH v7 2/3] soc: qcom: rpmh: Update dirty flag only when data changes From: Stephen Boyd Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, agross@kernel.org, dianders@chromium.org, rnayak@codeaurora.org, ilina@codeaurora.org, lsrao@codeaurora.org, Maulik Shah To: Maulik Shah , bjorn.andersson@linaro.org, evgreen@chromium.org, mka@chromium.org Date: Wed, 26 Feb 2020 14:43:23 -0800 Message-ID: <158275700389.177367.5843608826404724304@swboyd.mtv.corp.google.com> User-Agent: alot/0.9 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Quoting Maulik Shah (2020-02-25 21:27:12) > Currently rpmh ctrlr dirty flag is set for all cases regardless > of data is really changed or not. Add changes to update it when > data is updated to newer values. >=20 > Also move dirty flag updates to happen from within cache_lock. >=20 > Signed-off-by: Maulik Shah > Reviewed-by: Srinivas Rao L Probably worth adding a Fixes tag here? Doesn't make sense to mark something dirty when it isn't changed. > --- > drivers/soc/qcom/rpmh.c | 21 ++++++++++++++++----- > 1 file changed, 16 insertions(+), 5 deletions(-) >=20 > diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c > index eb0ded0..83ba4e0 100644 > --- a/drivers/soc/qcom/rpmh.c > +++ b/drivers/soc/qcom/rpmh.c > @@ -139,20 +139,27 @@ static struct cache_req *cache_rpm_request(struct r= pmh_ctrlr *ctrlr, > existing: > switch (state) { > case RPMH_ACTIVE_ONLY_STATE: > - if (req->sleep_val !=3D UINT_MAX) > + if (req->sleep_val !=3D UINT_MAX) { > req->wake_val =3D cmd->data; > + ctrlr->dirty =3D true; > + } > break; > case RPMH_WAKE_ONLY_STATE: > - req->wake_val =3D cmd->data; > + if (req->wake_val !=3D cmd->data) { > + req->wake_val =3D cmd->data; > + ctrlr->dirty =3D true; > + } > break; > case RPMH_SLEEP_STATE: > - req->sleep_val =3D cmd->data; > + if (req->sleep_val !=3D cmd->data) { > + req->sleep_val =3D cmd->data; > + ctrlr->dirty =3D true; > + } > break; > default: > break; Please remove the default case. There are only three states in the enum. The compiler will warn if a switch statement doesn't cover all cases and we'll know to add something here if another enum value is added in the future. > } > =20 > - ctrlr->dirty =3D true; > unlock: > spin_unlock_irqrestore(&ctrlr->cache_lock, flags); > =20 > @@ -323,6 +331,7 @@ static void invalidate_batch(struct rpmh_ctrlr *ctrlr) > list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list) > kfree(req); > INIT_LIST_HEAD(&ctrlr->batch_cache); > + ctrlr->dirty =3D true; > spin_unlock_irqrestore(&ctrlr->cache_lock, flags); > } > =20 > @@ -456,6 +465,7 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum= rpmh_state state, > int rpmh_flush(struct rpmh_ctrlr *ctrlr) > { > struct cache_req *p; > + unsigned long flags; > int ret; > =20 > if (!ctrlr->dirty) { > @@ -488,7 +498,9 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr) > return ret; > } > =20 > + spin_lock_irqsave(&ctrlr->cache_lock, flags); > ctrlr->dirty =3D false; > + spin_unlock_irqrestore(&ctrlr->cache_lock, flags); So we take the spinlock to update it here. But we don't hold the spinlock to test for !dirty up above. Seems like either rpmh_flush() can only be called sequentially, or the lock added here needs to be held during the whole flush. Which way is it?