From patchwork Mon Mar 20 14:43:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rob Clark X-Patchwork-Id: 665256 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 C4472C6FD1D for ; Mon, 20 Mar 2023 14:46:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232009AbjCTOqw (ORCPT ); Mon, 20 Mar 2023 10:46:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231899AbjCTOqR (ORCPT ); Mon, 20 Mar 2023 10:46:17 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3C79D302; Mon, 20 Mar 2023 07:45:10 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id p3-20020a17090a74c300b0023f69bc7a68so8146731pjl.4; Mon, 20 Mar 2023 07:45:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679323509; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=4LG2BAueGKKjRd5oOzkHW01KAXz7hJtO0YTeAZX7ebQ=; b=JYMfuqbtpiJILVkp0uoqa+oBsFme/4zOTzeVWYi3j3wR1ZQJWuMq7gV27NVroQ4Cof DvrYwJDRdr8vjUe7AoOTjec4wKPvjzpSGWLEwjaFkMJH0s8z+PQvoCMmcpojocLE7ybO oo+/Hl2TVSIoCQa+s4zQECFi1GZGH4VbTC86Yqlf91CDneoARc4TOJ4Z2guCXmZDIpSu /196tgzmV3xQEvnInxfSyu1LNUDP3vSbz96LAF3Eqc21Kvo8zow4uMY7aNpcZ4+NT4Yg MDg9DNeVPHKmg+hxMcvtXfab3OuON64cpe+DAyLDIvSqDWJdJRf7qPJfP/BVFmTravPm rQuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679323509; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=4LG2BAueGKKjRd5oOzkHW01KAXz7hJtO0YTeAZX7ebQ=; b=UrNvbjjWzYc5ua1kh5fogAC/kGvNkeEO/mH/8s/RbZZnP5042J0uXChEEoknNxGfyL UH0zwFqJX5eCROH24/M7uqIub0l6hBYTbUytYna8balEm6JVHnQ11PrV41dFdzSDCIY8 R0ra9MXwCNmEKUHi231Ff/MMMmnYXA+w2Ohl9AtMfi+iYijV0rdbnsbLxlnJonftPWBi vNQy1B4vI7N7juWymju54QnKUyavLrZlede47FenT4ZvGXRY5U0MPlL2eMJLgFKBylXX pyBojVIwStxyzXRLswXcxcsIJ/XrVDiYBLfNkJTLVGORmOWVQmZBb6I7HPruWKnV38Jb IesA== X-Gm-Message-State: AO0yUKWBbmQ1kD6WIYSIHf1CX+ZiTOVHuCM010AlE4lYEfCYVXjrExMj dF4i+Z6WxaAITxPJYwZc1Uw= X-Google-Smtp-Source: AK7set8ZMssF9rVaP9Q2tyqSeIvwgvafCYLFB4nuIVnqISbFD6NVpbGZbgq3RCYIRz5Qz1iGPiJ1mg== X-Received: by 2002:a17:902:c40a:b0:1a1:b9e0:fa1c with SMTP id k10-20020a170902c40a00b001a1b9e0fa1cmr10839593plk.0.1679323509573; Mon, 20 Mar 2023 07:45:09 -0700 (PDT) Received: from localhost ([2a00:79e1:abd:4a00:61b:48ed:72ab:435b]) by smtp.gmail.com with ESMTPSA id io7-20020a17090312c700b001a1ca6dc38csm2920651plb.118.2023.03.20.07.45.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Mar 2023 07:45:09 -0700 (PDT) From: Rob Clark To: dri-devel@lists.freedesktop.org Cc: Daniel Vetter , freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, Rob Clark , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Greg Kroah-Hartman , linux-pm@vger.kernel.org (open list:POWER MANAGEMENT CORE), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx Date: Mon, 20 Mar 2023 07:43:40 -0700 Message-Id: <20230320144356.803762-19-robdclark@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230320144356.803762-1-robdclark@gmail.com> References: <20230320144356.803762-1-robdclark@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org From: Rob Clark Similar to the previous patch, move the allocation out from under dev_pm_qos_mtx, by speculatively doing the allocation and handle any race after acquiring dev_pm_qos_mtx by freeing the redundant allocation. Signed-off-by: Rob Clark --- drivers/base/power/qos.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c index f3e0c6b65635..9cba334b3729 100644 --- a/drivers/base/power/qos.c +++ b/drivers/base/power/qos.c @@ -922,12 +922,16 @@ s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev) */ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val) { + struct dev_pm_qos_request *req = NULL; int ret; ret = dev_pm_qos_constraints_ensure_allocated(dev); if (ret) return ret; + if (!dev->power.qos->latency_tolerance_req) + req = kzalloc(sizeof(*req), GFP_KERNEL); + mutex_lock(&dev_pm_qos_mtx); if (!dev->power.qos->latency_tolerance_req) { @@ -940,7 +944,6 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val) ret = -EINVAL; goto out; } - req = kzalloc(sizeof(*req), GFP_KERNEL); if (!req) { ret = -ENOMEM; goto out; @@ -952,6 +955,13 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val) } dev->power.qos->latency_tolerance_req = req; } else { + /* + * If we raced with another thread to allocate the request, + * simply free the redundant allocation and move on. + */ + if (req) + kfree(req); + if (val < 0) { __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE); ret = 0;