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 CC70DC4332F for ; Wed, 23 Mar 2022 14:56:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244961AbiCWO5q (ORCPT ); Wed, 23 Mar 2022 10:57:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244933AbiCWO5k (ORCPT ); Wed, 23 Mar 2022 10:57:40 -0400 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 895767DE23 for ; Wed, 23 Mar 2022 07:56:10 -0700 (PDT) Received: by mail-ej1-x62e.google.com with SMTP id bi12so3393163ejb.3 for ; Wed, 23 Mar 2022 07:56:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=xxpZ0iiJJ0ZwZEvYkcJ55MAH2/mjQ7Nkl8lEGJi9pe8=; b=LABB1GCxIPlD3luxLyc/Nvl+Hx/y317qPwHAgq23XvnHF9qpUBg7Oj4qKR9m2oKy9Z nLHPjFsSVxbqnfMNTml3G5XFtYhv8f8ntalWyDLPzFpp/dHrB+gFda+AuFQOaMhvDpOG lVJ8tx+kfAFLsN1d7jnDqXAnP4HnCw5VLTupQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=xxpZ0iiJJ0ZwZEvYkcJ55MAH2/mjQ7Nkl8lEGJi9pe8=; b=g61D0WCUVUGFeF9yAvYF4FjVAeiAriee/cn6pNH+I4V5OxaqVwTpiGEpoNYBUAinaP BPE5y66s7LvlP8JgHbv+0EEzoEoGgMA0dHctM5y+EgSIHoFXetu3S7tP+3Dw/BbGd290 z2A5X/bFuKWqXQ+Hv6Jl0PTJw4h776l7dU5NcFCCRRTs6hTR6xqF6vCgLVFRpwwKzIEt 7OEpKFV98pKn0Xf5AazN42TlR97l8xw12JAJsN04PhM9zPF7sCNWLJAq5ujxlOXbYmw/ LNt1hzlbYXy5ePqW006YkqgLbIHjXXQwGHu6izasyU7+FU1sNVw4/cWzyRx9+mLXsXFD XLIg== X-Gm-Message-State: AOAM531uCQy2RMmJZ8jywsIMMY5SXau8890Mv8CNO/ikI8B6sQ5Uq9Sj 5Qj5xrLqZEl1D/QetM/luRhJFQ== X-Google-Smtp-Source: ABdhPJyFFyzCsMB02alxju10p2mtcDMblMiJlaXPaFNhnOhkRjAQ/fDW1gf6qTgwYf+nZz7WQmnLzQ== X-Received: by 2002:a17:906:57c1:b0:6d6:da73:e9c0 with SMTP id u1-20020a17090657c100b006d6da73e9c0mr363734ejr.45.1648047369103; Wed, 23 Mar 2022 07:56:09 -0700 (PDT) Received: from prevas-ravi.tritech.se ([80.208.64.233]) by smtp.gmail.com with ESMTPSA id p14-20020a05640210ce00b00413211746d4sm77256edu.51.2022.03.23.07.56.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Mar 2022 07:56:08 -0700 (PDT) From: Rasmus Villemoes To: Tejun Heo , Lai Jiangshan Cc: =?UTF-8?q?Andr=C3=A9=20Pribil?= , Steven Walter , Oleksij Rempel , Esben Haabendal , Jiri Slaby , Pengutronix Kernel Team , Peter Hurley , linux-rt-users@vger.kernel.org, Rasmus Villemoes , linux-kernel@vger.kernel.org Subject: [RFC PATCH 2/2] workqueue: update sysfs handlers, allow setting RT policies Date: Wed, 23 Mar 2022 15:56:00 +0100 Message-Id: <20220323145600.2156689-3-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220323145600.2156689-1-linux@rasmusvillemoes.dk> References: <20220323145600.2156689-1-linux@rasmusvillemoes.dk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For this POC, this (ab)uses the "nice" attribute. It's of course not exactly pretty, but it avoids the problem of "what to show in the xyz file when using SCHED_NORMAL, and what to show in the nice file when using SCHED_RR/SCHED_FIFO". It's backwards-compatible, in that a bare integer is interpreted as a nice value, while an integer prefixed by "fifo:" or "rr:" chooses that RT scheduling policy with the associated value as the priority. The show method of course reflects what the store method accepts. Signed-off-by: Rasmus Villemoes --- kernel/workqueue.c | 54 ++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 47 insertions(+), 7 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 9eb2ff7bcc04..a97f1aff809e 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5538,13 +5538,34 @@ static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr, char *buf) { struct workqueue_struct *wq = dev_to_wq(dev); - int written; + struct workqueue_attrs *wqattrs; + const char *pfx; + int val; mutex_lock(&wq->mutex); - written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice); + wqattrs = wq->unbound_attrs; + switch (wqattrs->policy) { + case SCHED_NORMAL: + pfx = ""; + val = wqattrs->nice; + break; + case SCHED_FIFO: + pfx = "fifo:"; + val = wqattrs->priority; + break; + case SCHED_RR: + pfx = "rr:"; + val = wqattrs->priority; + break; + default: + /* Shouldn't happen. */ + pfx = NULL; + } mutex_unlock(&wq->mutex); - return written; + if (!pfx) + return -EIO; + return scnprintf(buf, PAGE_SIZE, "%s%d\n", pfx, val); } /* prepare workqueue_attrs for sysfs store operations */ @@ -5568,6 +5589,24 @@ static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, struct workqueue_struct *wq = dev_to_wq(dev); struct workqueue_attrs *attrs; int ret = -ENOMEM; + int policy, val; + + if (sscanf(buf, "fifo:%d", &val) == 1) + policy = SCHED_FIFO; + else if (sscanf(buf, "rr:%d", &val) == 1) + policy = SCHED_RR; + else if (sscanf(buf, "%d", &val) == 1) + policy = SCHED_NORMAL; + else + return -EINVAL; + + if (policy == SCHED_NORMAL) { + if (val < MIN_NICE || val > MAX_NICE) + return -EINVAL; + } else { + if (val <= 0 || val >= MAX_RT_PRIO) + return -EINVAL; + } apply_wqattrs_lock(); @@ -5575,11 +5614,12 @@ static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, if (!attrs) goto out_unlock; - if (sscanf(buf, "%d", &attrs->nice) == 1 && - attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE) - ret = apply_workqueue_attrs_locked(wq, attrs); + attrs->policy = policy; + if (policy == SCHED_NORMAL) + attrs->nice = val; else - ret = -EINVAL; + attrs->priority = val; + ret = apply_workqueue_attrs_locked(wq, attrs); out_unlock: apply_wqattrs_unlock(); -- 2.31.1