From nobody Wed Apr 8 18:38:48 2026 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 919EEECAAA1 for ; Fri, 28 Oct 2022 09:35:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230113AbiJ1Jf2 (ORCPT ); Fri, 28 Oct 2022 05:35:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229719AbiJ1JfG (ORCPT ); Fri, 28 Oct 2022 05:35:06 -0400 Received: from mail-wm1-x332.google.com (mail-wm1-x332.google.com [IPv6:2a00:1450:4864:20::332]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C2EA52E58 for ; Fri, 28 Oct 2022 02:35:04 -0700 (PDT) Received: by mail-wm1-x332.google.com with SMTP id c3-20020a1c3503000000b003bd21e3dd7aso6137705wma.1 for ; Fri, 28 Oct 2022 02:35:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=references:in-reply-to:message-id:date:subject:cc:to:from:from:to :cc:subject:date:message-id:reply-to; bh=Oeg4H6o/dcPx5AQqGWzAkKIEqb6LjGQnX/XTYoDflfQ=; b=HctYI/C7VcSDtt3f/hIEQL/8vpU0BuX0Hwu9pgY55Md1D7JqQ6c+9U39THwyDbF6BH T6EUa274nL0DFvpqVPcPS+0JWT6vm/Z6ky+KN7M9+ZoFjbK8/wb31oHPihhIlLM5dgHE dq+hFK7F2pLw5hnKH5vKGh9GlEc2KONNX6iPbzjnXyKuAA8+JnAS6Bw0idMMnswjxL38 Ouw5JhFh9Nh6TQBRW5pOBdSgAhOCj1RdJ4w+HkvBQvD/mp+iBfQj1vXDCETu6/UNdfsB obg2Zh7vwDrbqNjjjYenQwZhkpkxUONDoeWf/xPWqpqlGPCqOFjWY+V752dNYIFJHAro T98A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=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=Oeg4H6o/dcPx5AQqGWzAkKIEqb6LjGQnX/XTYoDflfQ=; b=EZwSdmwaQ2+pOja3YfzTtw6vfMfNTk/PZRldhIk03DyqK7KqLENHiY8eY/oOgG1cek lOEazsLcPRw4H0VYJThHtaVBLspyMSf0TR844u2ij6sSJ/A3kL5/HIANgjrJLkhB+jyc NHd117p0DTNgQhXf29OX+erWH46+CLKyusr1ydfeUZmm/4V4IcxuthJnYZALN53HRXdv kRJSvpaYXxEuBiDKp33H9j4YCpE8cyDU+0Fzi7s7gU0UgpDz9XsX/dCOpWUU66Zk6hLN N1VtkSX7VSkRy4oxAU3y3rJQLgTjm9D1jtVOLnt2l0nCEAUTEOo1jaG5DJXxlLcqBnRs /F5Q== X-Gm-Message-State: ACrzQf2syE9nuOGtdWkxR4RKHulHk5M0WZMnqgCE4wquPaBmjNtZbsyh yRaFExEGpBx00N+AypSWHf0yFw== X-Google-Smtp-Source: AMsMyM45PTAucK12EKuGrQvxLrfjpzn8/VrOlBGQIqApr8MXGU9nq+pBKaowDZQbEO1m3YjWLBxV7g== X-Received: by 2002:a05:6000:2a7:b0:22f:bb40:83f8 with SMTP id l7-20020a05600002a700b0022fbb4083f8mr34795320wry.288.1666949702527; Fri, 28 Oct 2022 02:35:02 -0700 (PDT) Received: from localhost.localdomain ([2a01:e0a:f:6020:c12b:b448:f0a9:83ef]) by smtp.gmail.com with ESMTPSA id k3-20020a05600c1c8300b003c6b7f5567csm10909426wms.0.2022.10.28.02.35.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Oct 2022 02:35:01 -0700 (PDT) From: Vincent Guittot To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, linux-kernel@vger.kernel.org, parth@linux.ibm.com Cc: qais.yousef@arm.com, chris.hyser@oracle.com, patrick.bellasi@matbug.net, David.Laight@aculab.com, pjt@google.com, pavel@ucw.cz, tj@kernel.org, qperret@google.com, tim.c.chen@linux.intel.com, joshdon@google.com, timj@gnu.org, kprateek.nayak@amd.com, yu.c.chen@intel.com, youssefesmat@chromium.org, joel@joelfernandes.org, Vincent Guittot Subject: [PATCH v7 4/9] sched: Allow sched_{get,set}attr to change latency_nice of the task Date: Fri, 28 Oct 2022 11:33:58 +0200 Message-Id: <20221028093403.6673-5-vincent.guittot@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20221028093403.6673-1-vincent.guittot@linaro.org> References: <20221028093403.6673-1-vincent.guittot@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Parth Shah Introduce the latency_nice attribute to sched_attr and provide a mechanism to change the value with the use of sched_setattr/sched_getattr syscall. Also add new flag "SCHED_FLAG_LATENCY_NICE" to hint the change in latency_nice of the task on every sched_setattr syscall. Signed-off-by: Parth Shah [rebase and add a dedicated __setscheduler_latency ] Signed-off-by: Vincent Guittot --- include/uapi/linux/sched.h | 4 +++- include/uapi/linux/sched/types.h | 19 +++++++++++++++++++ kernel/sched/core.c | 24 ++++++++++++++++++++++++ tools/include/uapi/linux/sched.h | 4 +++- 4 files changed, 49 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index 3bac0a8ceab2..b2e932c25be6 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -132,6 +132,7 @@ struct clone_args { #define SCHED_FLAG_KEEP_PARAMS 0x10 #define SCHED_FLAG_UTIL_CLAMP_MIN 0x20 #define SCHED_FLAG_UTIL_CLAMP_MAX 0x40 +#define SCHED_FLAG_LATENCY_NICE 0x80 =20 #define SCHED_FLAG_KEEP_ALL (SCHED_FLAG_KEEP_POLICY | \ SCHED_FLAG_KEEP_PARAMS) @@ -143,6 +144,7 @@ struct clone_args { SCHED_FLAG_RECLAIM | \ SCHED_FLAG_DL_OVERRUN | \ SCHED_FLAG_KEEP_ALL | \ - SCHED_FLAG_UTIL_CLAMP) + SCHED_FLAG_UTIL_CLAMP | \ + SCHED_FLAG_LATENCY_NICE) =20 #endif /* _UAPI_LINUX_SCHED_H */ diff --git a/include/uapi/linux/sched/types.h b/include/uapi/linux/sched/ty= pes.h index f2c4589d4dbf..db1e8199e8c8 100644 --- a/include/uapi/linux/sched/types.h +++ b/include/uapi/linux/sched/types.h @@ -10,6 +10,7 @@ struct sched_param { =20 #define SCHED_ATTR_SIZE_VER0 48 /* sizeof first published struct */ #define SCHED_ATTR_SIZE_VER1 56 /* add: util_{min,max} */ +#define SCHED_ATTR_SIZE_VER2 60 /* add: latency_nice */ =20 /* * Extended scheduling parameters data structure. @@ -98,6 +99,22 @@ struct sched_param { * scheduled on a CPU with no more capacity than the specified value. * * A task utilization boundary can be reset by setting the attribute to -1. + * + * Latency Tolerance Attributes + * =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D + * + * A subset of sched_attr attributes allows to specify the relative latency + * requirements of a task with respect to the other tasks running/queued i= n the + * system. + * + * @ sched_latency_nice task's latency_nice value + * + * The latency_nice of a task can have any value in a range of + * [MIN_LATENCY_NICE..MAX_LATENCY_NICE]. + * + * A task with latency_nice with the value of LATENCY_NICE_MIN can be + * taken for a task requiring a lower latency as opposed to the task with + * higher latency_nice. */ struct sched_attr { __u32 size; @@ -120,6 +137,8 @@ struct sched_attr { __u32 sched_util_min; __u32 sched_util_max; =20 + /* latency requirement hints */ + __s32 sched_latency_nice; }; =20 #endif /* _UAPI_LINUX_SCHED_TYPES_H */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 54544353025b..b2accc9da4fe 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7318,6 +7318,14 @@ static void __setscheduler_params(struct task_struct= *p, p->rt_priority =3D attr->sched_priority; p->normal_prio =3D normal_prio(p); set_load_weight(p, true); + +} + +static void __setscheduler_latency(struct task_struct *p, + const struct sched_attr *attr) +{ + if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE) + p->latency_nice =3D attr->sched_latency_nice; } =20 /* @@ -7460,6 +7468,13 @@ static int __sched_setscheduler(struct task_struct *= p, return retval; } =20 + if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE) { + if (attr->sched_latency_nice > MAX_LATENCY_NICE) + return -EINVAL; + if (attr->sched_latency_nice < MIN_LATENCY_NICE) + return -EINVAL; + } + if (pi) cpuset_read_lock(); =20 @@ -7494,6 +7509,9 @@ static int __sched_setscheduler(struct task_struct *p, goto change; if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) goto change; + if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE && + attr->sched_latency_nice !=3D p->latency_nice) + goto change; =20 p->sched_reset_on_fork =3D reset_on_fork; retval =3D 0; @@ -7582,6 +7600,7 @@ static int __sched_setscheduler(struct task_struct *p, __setscheduler_params(p, attr); __setscheduler_prio(p, newprio); } + __setscheduler_latency(p, attr); __setscheduler_uclamp(p, attr); =20 if (queued) { @@ -7792,6 +7811,9 @@ static int sched_copy_attr(struct sched_attr __user *= uattr, struct sched_attr *a size < SCHED_ATTR_SIZE_VER1) return -EINVAL; =20 + if ((attr->sched_flags & SCHED_FLAG_LATENCY_NICE) && + size < SCHED_ATTR_SIZE_VER2) + return -EINVAL; /* * XXX: Do we want to be lenient like existing syscalls; or do we want * to be strict and return an error on out-of-bounds values? @@ -8029,6 +8051,8 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sch= ed_attr __user *, uattr, get_params(p, &kattr); kattr.sched_flags &=3D SCHED_FLAG_ALL; =20 + kattr.sched_latency_nice =3D p->latency_nice; + #ifdef CONFIG_UCLAMP_TASK /* * This could race with another potential updater, but this is fine diff --git a/tools/include/uapi/linux/sched.h b/tools/include/uapi/linux/sc= hed.h index 3bac0a8ceab2..b2e932c25be6 100644 --- a/tools/include/uapi/linux/sched.h +++ b/tools/include/uapi/linux/sched.h @@ -132,6 +132,7 @@ struct clone_args { #define SCHED_FLAG_KEEP_PARAMS 0x10 #define SCHED_FLAG_UTIL_CLAMP_MIN 0x20 #define SCHED_FLAG_UTIL_CLAMP_MAX 0x40 +#define SCHED_FLAG_LATENCY_NICE 0x80 =20 #define SCHED_FLAG_KEEP_ALL (SCHED_FLAG_KEEP_POLICY | \ SCHED_FLAG_KEEP_PARAMS) @@ -143,6 +144,7 @@ struct clone_args { SCHED_FLAG_RECLAIM | \ SCHED_FLAG_DL_OVERRUN | \ SCHED_FLAG_KEEP_ALL | \ - SCHED_FLAG_UTIL_CLAMP) + SCHED_FLAG_UTIL_CLAMP | \ + SCHED_FLAG_LATENCY_NICE) =20 #endif /* _UAPI_LINUX_SCHED_H */ --=20 2.17.1