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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 6395BC433DF for ; Tue, 30 Jun 2020 14:56:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 477BA20675 for ; Tue, 30 Jun 2020 14:56:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389158AbgF3Oz6 (ORCPT ); Tue, 30 Jun 2020 10:55:58 -0400 Received: from mail-ed1-f67.google.com ([209.85.208.67]:37638 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729260AbgF3Oz6 (ORCPT ); Tue, 30 Jun 2020 10:55:58 -0400 Received: by mail-ed1-f67.google.com with SMTP id g20so16305075edm.4 for ; Tue, 30 Jun 2020 07:55:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:message-id:date:mime-version; bh=LRlTz/DoSdGeE0PKox/YqTRF8d9xjO56YImrwMYM7ck=; b=F7kz+gdoWnyIb3wDLor1vqirnm/RK6cF4y/9b9YzI2p7BHaLqqmdb20sD8krxyOslR KHVD8epR7NpW8X72n5fBB6cPXjekKcQXwVaGne1eRtJTu59PwMM8bQelPf5TEndW4afv BzVmk3AMLirRS2xgRzdqHOojrsxzyrJROXNyF5CTRifki7779z+yy75jxzHP1fpzMdAM hkmjFJ9+Fvrv1VCKOT8mviqC0glHNhVGzgojvraNQL/cvOSYk5QdwSy22kX1cvYG6Goz XwQQmMbQeh59sX4FZF39DBESNIZL4TTIoWOZrOZJl6iScgcQdb3wM4x58FdGi+EeTXkg a23g== X-Gm-Message-State: AOAM531lfCPPfpVvEj1ERi/YmYo162J+i9WMQ6Og2sbRp8sgqfwToTWu Mn9VHPXP1HFY4vaz/8BtuKj6DHvXevw= X-Google-Smtp-Source: ABdhPJyrcIQSOJ4j8u0X6wQj4NfrkkkYfLiuvCIQI50ZdXQ7ihNvwsVs8V8r/ViyBrbf1JYnYP75CA== X-Received: by 2002:a05:6402:203a:: with SMTP id ay26mr12564870edb.276.1593528955733; Tue, 30 Jun 2020 07:55:55 -0700 (PDT) Received: from darkstar ([2a04:ee41:4:5025:8295:1d2:ca0d:985e]) by smtp.gmail.com with ESMTPSA id t6sm2244842ejc.40.2020.06.30.07.55.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jun 2020 07:55:54 -0700 (PDT) References: <20200629162633.8800-1-qais.yousef@arm.com> <20200629162633.8800-3-qais.yousef@arm.com> <87366dnfaq.derkling@matbug.net> <20200630094623.hnlqtgavauqlsuyd@e107158-lin.cambridge.arm.com> User-agent: mu4e 1.4.10; emacs 26.3 From: Patrick Bellasi To: Qais Yousef Cc: Ingo Molnar , Peter Zijlstra , Valentin Schneider , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Chris Redpath , Lukasz Luba , linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 2/2] sched/uclamp: Protect uclamp fast path code with static key In-reply-to: <20200630094623.hnlqtgavauqlsuyd@e107158-lin.cambridge.arm.com> Message-ID: <87zh8kmwlt.derkling@matbug.net> Date: Tue, 30 Jun 2020 16:55:42 +0200 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Qais, sorry for commenting on v5 with a v6 already posted, but... ... I cannot keep up with your re-spinning rate ;) More importantly, perhaps you missed to comment on one of my previous points. Will have a better look at the rest of v6 later today. Cheers, Patrick On Tue, Jun 30, 2020 at 11:46:24 +0200, Qais Yousef wrote... > On 06/30/20 10:11, Patrick Bellasi wrote: >> On Mon, Jun 29, 2020 at 18:26:33 +0200, Qais Yousef wrote... [...] >> > + >> > +static inline bool uclamp_is_enabled(void) >> > +{ >> > + return static_branch_likely(&sched_uclamp_used); >> > +} >> >> Looks like here we mix up terms, which can be confusing. >> AFAIKS, we use: >> - *_enabled for the sched class flags (compile time) >> - *_used for the user-space opting in (run time) > > I wanted to add a comment here. > > I can rename it to uclamp_is_used() if you want. In my previous message I was mostly asking about this: >> Thus, perhaps we can just use the same pattern used by the >> sched_numa_balancing static key: >> >> $ git grep sched_numa_balancing >> kernel/sched/core.c:DEFINE_STATIC_KEY_FALSE(sched_numa_balancing); >> kernel/sched/core.c: static_branch_enable(&sched_numa_balancing); >> kernel/sched/core.c: static_branch_disable(&sched_numa_balancing); >> kernel/sched/core.c: int state = static_branch_likely(&sched_numa_balancing); >> kernel/sched/fair.c: if (!static_branch_likely(&sched_numa_balancing)) >> kernel/sched/fair.c: if (!static_branch_likely(&sched_numa_balancing)) >> kernel/sched/fair.c: if (!static_branch_likely(&sched_numa_balancing)) >> kernel/sched/fair.c: if (static_branch_unlikely(&sched_numa_balancing)) >> kernel/sched/sched.h:extern struct static_key_false sched_numa_balancing; >> >> IOW: unconditionally define sched_uclamp_used as non static in core.c, >> and use it directly on schedutil too. So, what about this instead of adding the (renamed) method above?