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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 BC7E3C4BA06 for ; Thu, 27 Feb 2020 05:33:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B0112468C for ; Thu, 27 Feb 2020 05:33:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="dTZZPicr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728526AbgB0FdF (ORCPT ); Thu, 27 Feb 2020 00:33:05 -0500 Received: from mail26.static.mailgun.info ([104.130.122.26]:16722 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728453AbgB0FdE (ORCPT ); Thu, 27 Feb 2020 00:33:04 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1582781583; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=z5QCR+5CQZXJeKsaK1cOJr/DwfcXkvDbVqkcSQPZeS0=; b=dTZZPicrsXfQx0LtihyTIpnlHtEWoqFTkRP1prDVrKhHV90kqVDxDKcB7xdpfBBNHmEML5XO t6VDN65CA4TruDhNkkzKRJXsPxjRekf7l3aYL0N3pa+vBrBf6tXmO3J8lk93wKN1lJrokOUn zZ4X+Tp+okHkJ5TY5/5cvVopfjA= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5e57547a.7f45e60cea08-smtp-out-n02; Thu, 27 Feb 2020 05:32:42 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 1C20FC4479F; Thu, 27 Feb 2020 05:32:41 +0000 (UTC) Received: from [10.206.13.37] (blr-c-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mkshah) by smtp.codeaurora.org (Postfix) with ESMTPSA id 5888BC43383; Thu, 27 Feb 2020 05:32:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5888BC43383 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=mkshah@codeaurora.org Subject: Re: [PATCH v7 2/3] soc: qcom: rpmh: Update dirty flag only when data changes To: Stephen Boyd , bjorn.andersson@linaro.org, evgreen@chromium.org, mka@chromium.org 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 References: <1582694833-9407-1-git-send-email-mkshah@codeaurora.org> <1582694833-9407-3-git-send-email-mkshah@codeaurora.org> <158275700389.177367.5843608826404724304@swboyd.mtv.corp.google.com> From: Maulik Shah Message-ID: <3f7c689b-700a-1d76-505e-76446c62439f@codeaurora.org> Date: Thu, 27 Feb 2020 11:02:34 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <158275700389.177367.5843608826404724304@swboyd.mtv.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-GB Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 2/27/2020 4:13 AM, Stephen Boyd wrote: > 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. >> >> Also move dirty flag updates to happen from within cache_lock. >> >> 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. Done. will update in v8. >> --- >> drivers/soc/qcom/rpmh.c | 21 ++++++++++++++++----- >> 1 file changed, 16 insertions(+), 5 deletions(-) >> >> 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 rpmh_ctrlr *ctrlr, >> existing: >> switch (state) { >> case RPMH_ACTIVE_ONLY_STATE: >> - if (req->sleep_val != UINT_MAX) >> + if (req->sleep_val != UINT_MAX) { >> req->wake_val = cmd->data; >> + ctrlr->dirty = true; >> + } >> break; >> case RPMH_WAKE_ONLY_STATE: >> - req->wake_val = cmd->data; >> + if (req->wake_val != cmd->data) { >> + req->wake_val = cmd->data; >> + ctrlr->dirty = true; >> + } >> break; >> case RPMH_SLEEP_STATE: >> - req->sleep_val = cmd->data; >> + if (req->sleep_val != cmd->data) { >> + req->sleep_val = cmd->data; >> + ctrlr->dirty = 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. Done. >> } >> >> - ctrlr->dirty = true; >> unlock: >> spin_unlock_irqrestore(&ctrlr->cache_lock, flags); >> >> @@ -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 = true; >> spin_unlock_irqrestore(&ctrlr->cache_lock, flags); >> } >> >> @@ -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; >> >> if (!ctrlr->dirty) { >> @@ -488,7 +498,9 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr) >> return ret; >> } >> >> + spin_lock_irqsave(&ctrlr->cache_lock, flags); >> ctrlr->dirty = 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? Thanks, i will remove !ctrlr->dirty check within rpmh_flush() as currently we invoke it only when caches are dirty. Last cpu going down can first check dirty flag outside rpmh_flush() and decide to invoke it accoringly. -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation