From nobody Sun Nov 24 11:08:31 2024 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6E46318FDCE for ; Wed, 6 Nov 2024 02:57:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730861826; cv=none; b=NTTpUssbb4iZtpCx1NchEDitoLAB7eiNyFexUQlb+bDAjAHJdwLe1QlUvB3QWy/gP5YPlSxTk1V2E8TY1ot60GP4X9xcLnzVkQIPd4HkLsIQcDxQXlGf+CgjI6pvDu6aWptFVKwSyoUia85JYNxZbEQSBFqdEDwddqAeS8Fjvek= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730861826; c=relaxed/simple; bh=h6TFkk3UWQbVFEnbht6yNjdbKrdQbKC/+TdjrBRVTyU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=bIS5AigEqyTyxq0bPzqRycC9RgVwrzIplrN5mVyliYTpAEWvsc2IDULafz89nWnTnUif6Q79mTdo+uym7MnQbQ1Pcl4nSITsvfCaDFnpaHan8D6Q+66/iNsg83Y0dCM5HtqGweYdYbv/Fy1hpAIEDbxmrq6nepYfqkJRDmoL5Nk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=NovCl0/k; arc=none smtp.client-ip=209.85.128.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NovCl0/k" Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-6ea863ecfe9so73139467b3.3 for ; Tue, 05 Nov 2024 18:57:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1730861823; x=1731466623; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=FAcghQf6R6kdCkj8rTfS8LDuV3Z5MU4VGrydA8s7ieg=; b=NovCl0/k0OKEjUkIuGpuv7qCCz5NZHz9ajR5bExOPxLn3dUf8KVVWfF4/ZsFMEi4X5 ongeIzjq0UOFTIlXqJVi+oM1zr3+tOKs9s7xrQAl2+KUnXi20L2p3lm0seF1fD2ZCMyu BGGNZ4j7DnBsuPYPnkFMsfngUrnRDbwIJpQBT1s8WMRKs/P4P5sfDiVkf/smhnZeDhbY WMbbLDYzCxZfXU/j31zK07VlGEAUXD64o/g9jk6XGamucIIftVB76iUYUJX2XQbfjsjk 9Y9CNzAG+mAXJ822za3z2El2P9WEN93VqZe1A0C/28Z0cWCFWWtylnQEV0WngBuEI/gR cEUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730861823; x=1731466623; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=FAcghQf6R6kdCkj8rTfS8LDuV3Z5MU4VGrydA8s7ieg=; b=HNau6TC17SM6XU9ucOxdh0W5TCRV07sxbOFSQBj4SUU3x82J9odL1KevUrqtuSzGrL ndCskPHltEToC4f47A0HM3gbcxU9Bv8DzuHevxQGWYj3oDOJsrHzNBxIx84MVd+a5062 FmlvfOZ5EpZv+4/k1wEe6pfdNsbkhD05HZqIbGD23uIo13kBU3gOsd6/Qs/tZBaanJNv RmrSpFNDZbGsebnpxwYbAf2lESz5EAHxEXS3uJcOStQVwAk5FwalscimhaxbmA5zr/uY bZi5xp7pHDtMdidCwiCLvG5xw7iWAjFbOgozVHoM0cYUAjAWWAf7zBim/CEe/l78W8N6 ac0Q== X-Gm-Message-State: AOJu0YwD4LFfuCsDCQEyVjiGVGCx+hosZpQjfpCtRt6Gos2/BfxRXdWZ E0hSPpqGXnoLHy/9+8mlA50Wdt/IBgsjcFqeXlaguAbfk5Md0LHKndclkXi2MO0cV6V5ZcP6zye FRk9PSJKtuctU0MtoTkDZ6P6CFOf2FfJgkCGtLhEyGgYHUX0M5+AdIGipCT0tjhr3TUDcmLsl8G cJIWws52wEHeBKFaDp9Z62N9JRwlH8n8++ruUsTv2o20b1 X-Google-Smtp-Source: AGHT+IGUWP+GWTBSONfEMXEftSPgQpmB2+QGLi3H5/olrnBR57+co6NioocX80C16bXkHPB1fkvygZCa2qvS X-Received: from jstultz-noogler2.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:600]) (user=jstultz job=sendgmr) by 2002:a5b:91:0:b0:e28:f2a5:f1d with SMTP id 3f1490d57ef6-e3087a4ed65mr70312276.4.1730861822133; Tue, 05 Nov 2024 18:57:02 -0800 (PST) Date: Tue, 5 Nov 2024 18:56:41 -0800 In-Reply-To: <20241106025656.2326794-1-jstultz@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241106025656.2326794-1-jstultz@google.com> X-Mailer: git-send-email 2.47.0.199.ga7371fff76-goog Message-ID: <20241106025656.2326794-2-jstultz@google.com> Subject: [RFC][PATCH v13 1/7] sched: Add CONFIG_SCHED_PROXY_EXEC & boot argument to enable/disable From: John Stultz To: LKML Cc: John Stultz , Joel Fernandes , Qais Yousef , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Valentin Schneider , Steven Rostedt , Ben Segall , Zimuzo Ezeozue , Mel Gorman , Will Deacon , Waiman Long , Boqun Feng , "Paul E. McKenney" , Metin Kaya , Xuewen Yan , K Prateek Nayak , Thomas Gleixner , Daniel Lezcano , kernel-team@android.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a CONFIG_SCHED_PROXY_EXEC option, along with a boot argument sched_proxy_exec=3D that can be used to disable the feature at boot time if CONFIG_SCHED_PROXY_EXEC was enabled. Cc: Joel Fernandes Cc: Qais Yousef Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Valentin Schneider Cc: Steven Rostedt Cc: Ben Segall Cc: Zimuzo Ezeozue Cc: Mel Gorman Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng Cc: "Paul E. McKenney" Cc: Metin Kaya Cc: Xuewen Yan Cc: K Prateek Nayak Cc: Thomas Gleixner Cc: Daniel Lezcano Cc: kernel-team@android.com Tested-by: K Prateek Nayak Signed-off-by: John Stultz --- v7: * Switch to CONFIG_SCHED_PROXY_EXEC/sched_proxy_exec=3D as suggested by Metin Kaya. * Switch boot arg from =3Ddisable/enable to use kstrtobool(), which supports =3Dyes|no|1|0|true|false|on|off, as also suggested by Metin Kaya, and print a message when a boot argument is used. v8: * Move CONFIG_SCHED_PROXY_EXEC under Scheduler Features as Suggested by Metin * Minor rework reordering with split sched contexts patch v12: * Rework for selected -> donor renaming --- .../admin-guide/kernel-parameters.txt | 5 ++++ include/linux/sched.h | 13 +++++++++ init/Kconfig | 7 +++++ kernel/sched/core.c | 29 +++++++++++++++++++ kernel/sched/sched.h | 12 ++++++++ 5 files changed, 66 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 1518343bbe22..5152935b54b6 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5944,6 +5944,11 @@ sa1100ir [NET] See drivers/net/irda/sa1100_ir.c. =20 + sched_proxy_exec=3D [KNL] + Enables or disables "proxy execution" style + solution to mutex-based priority inversion. + Format: + sched_verbose [KNL,EARLY] Enables verbose scheduler debug messages. =20 schedstats=3D [KNL,X86] Enable or disable scheduled statistics. diff --git a/include/linux/sched.h b/include/linux/sched.h index a76e3d074a2a..2a47228a4808 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1609,6 +1609,19 @@ struct task_struct { */ }; =20 +#ifdef CONFIG_SCHED_PROXY_EXEC +DECLARE_STATIC_KEY_TRUE(__sched_proxy_exec); +static inline bool sched_proxy_exec(void) +{ + return static_branch_likely(&__sched_proxy_exec); +} +#else +static inline bool sched_proxy_exec(void) +{ + return false; +} +#endif + #define TASK_REPORT_IDLE (TASK_REPORT + 1) #define TASK_REPORT_MAX (TASK_REPORT_IDLE << 1) =20 diff --git a/init/Kconfig b/init/Kconfig index c521e1421ad4..a91c51850731 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -863,6 +863,13 @@ config UCLAMP_BUCKETS_COUNT =20 If in doubt, use the default value. =20 +config SCHED_PROXY_EXEC + bool "Proxy Execution" + default n + help + This option enables proxy execution, a mechanism for mutex-owning + tasks to inherit the scheduling context of higher priority waiters. + endmenu =20 # diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c57a79e34911..731ebd8614a9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -119,6 +119,35 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(sched_compute_energy_tp); =20 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); =20 +#ifdef CONFIG_SCHED_PROXY_EXEC +DEFINE_STATIC_KEY_TRUE(__sched_proxy_exec); +static int __init setup_proxy_exec(char *str) +{ + bool proxy_enable; + + if (kstrtobool(str, &proxy_enable)) { + pr_warn("Unable to parse sched_proxy_exec=3D\n"); + return 0; + } + + if (proxy_enable) { + pr_info("sched_proxy_exec enabled via boot arg\n"); + static_branch_enable(&__sched_proxy_exec); + } else { + pr_info("sched_proxy_exec disabled via boot arg\n"); + static_branch_disable(&__sched_proxy_exec); + } + return 1; +} +#else +static int __init setup_proxy_exec(char *str) +{ + pr_warn("CONFIG_SCHED_PROXY_EXEC=3Dn, so it cannot be enabled or disabled= at boot time\n"); + return 0; +} +#endif +__setup("sched_proxy_exec=3D", setup_proxy_exec); + #ifdef CONFIG_SCHED_DEBUG /* * Debugging: various feature bits diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index e51bf5a344d3..258db6ef8c70 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1147,10 +1147,15 @@ struct rq { */ unsigned int nr_uninterruptible; =20 +#ifdef CONFIG_SCHED_PROXY_EXEC + struct task_struct __rcu *donor; /* Scheduling context */ + struct task_struct __rcu *curr; /* Execution context */ +#else union { struct task_struct __rcu *donor; /* Scheduler context */ struct task_struct __rcu *curr; /* Execution context */ }; +#endif struct sched_dl_entity *dl_server; struct task_struct *idle; struct task_struct *stop; @@ -1347,10 +1352,17 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues= ); #define cpu_curr(cpu) (cpu_rq(cpu)->curr) #define raw_rq() raw_cpu_ptr(&runqueues) =20 +#ifdef CONFIG_SCHED_PROXY_EXEC +static inline void rq_set_donor(struct rq *rq, struct task_struct *t) +{ + rcu_assign_pointer(rq->donor, t); +} +#else static inline void rq_set_donor(struct rq *rq, struct task_struct *t) { /* Do nothing */ } +#endif =20 #ifdef CONFIG_SCHED_CORE static inline struct cpumask *sched_group_span(struct sched_group *sg); --=20 2.47.0.199.ga7371fff76-goog