From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A45F1B040E; Fri, 7 Feb 2025 22:39:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738967999; cv=none; b=YWdqnv/B48IED7Y5JLsEHhUtB9qJA6g9dToOXa2QpjaB9uIuq/86UyaEY5rEqZfxiuKfJZIroUJhojBU1lxtfJ34CEBsh5H4zwrCn3aPAsnXb/kNTKJZSI+zzWE2L4dlanKpsu664Ko457FjJMY8M6WkmNb9yoQOnn3myqI/GPM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738967999; c=relaxed/simple; bh=CkqyHQsJo+5JgwcQ+3Aney3H89UG2dd28pIxPBnkThc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fOoX6/fhlggfAkcp1ypbb3vCLAGBjvOndxreFdCm8i1CZgf6f+JFKXzNxI63f2Sz8cWfgEcWKq7zBsaotsKCEnIuoZydMvUkWkgRSoVOZ+l2+3eD+3LhbwDhs85xehz3ndUufJ744QFQGme8LFZ4pTrRmgEv8HFIGWHfsh7zpuc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Buo4wBT7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Buo4wBT7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99F1CC4CEE2; Fri, 7 Feb 2025 22:39:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738967998; bh=CkqyHQsJo+5JgwcQ+3Aney3H89UG2dd28pIxPBnkThc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Buo4wBT7WySW/cbrPBP+wB3qhkBQ8zFJhNDXrpHD67VpuPSgCDGgU43I2ExBeJV1I w3KEytqAB16A6TgmE/CTJGj1UiiRERNRb6h+CinduxI0njnEbr1BSdLNGGvzEJ9p82 xkYjKhTn6PvmmI0MdPjEEEiKWMsprsc0IcB8jkbjck/W53T/dvgCJ5yvBfhXOU4una Q2cT9vI5pxXWYmV8+F/pNzT/Vvtr4hUynBhoEPHek6BOqKCJGDgzdBmIUE7G5M3B5N +ewgiIMbsG4h5Iga3CGWAbBjCmJ6/82gilSELUs8/jlvRFRPVW3ce/01j5aDt6uLmf tdC1DLNZ7Q4RQ== Date: Fri, 7 Feb 2025 12:39:57 -1000 From: Tejun Heo To: Andrea Righi Cc: David Vernet , Changwoo Min , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Ian May , bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/6] sched_ext: idle: Introduce node-aware idle cpu kfunc helpers Message-ID: References: <20250207211104.30009-1-arighi@nvidia.com> <20250207211104.30009-7-arighi@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250207211104.30009-7-arighi@nvidia.com> Hello, On Fri, Feb 07, 2025 at 09:40:53PM +0100, Andrea Righi wrote: > +/** > + * scx_bpf_cpu_to_node - Return the NUMA node the given @cpu belongs to > + */ > +__bpf_kfunc int scx_bpf_cpu_to_node(s32 cpu) Maybe scx_bpf_cpu_node() to be in line with scx_bpf_task_cpu/cgroup()? > +{ > +#ifdef CONFIG_NUMA > + if (cpu < 0 || cpu >= nr_cpu_ids) > + return -EINVAL; Use ops_cpu_valid()? Otherwise, we can end up calling cpu_to_node() with an impossible CPU. Also, I don't think CPU -> node mapping function should be able to return an error value. It should just trigger ops error. > + > + return idle_cpu_to_node(cpu); This is contingent on scx_builtin_idle_per_node, right? It's confusing for CPU -> node mapping function to return NUMA_NO_NODE depending on an ops flag. Shouldn't this be a generic mapping function? > index 50e1499ae0935..caa1a80f9a60c 100644 > --- a/tools/sched_ext/include/scx/compat.bpf.h > +++ b/tools/sched_ext/include/scx/compat.bpf.h > @@ -130,6 +130,25 @@ bool scx_bpf_dispatch_vtime_from_dsq___compat(struct bpf_iter_scx_dsq *it__iter, > scx_bpf_now() : \ > bpf_ktime_get_ns()) > > +#define __COMPAT_scx_bpf_cpu_to_node(cpu) \ > + (bpf_ksym_exists(scx_bpf_cpu_to_node) ? \ > + scx_bpf_cpu_to_node(cpu) : 0) > + > +#define __COMPAT_scx_bpf_get_idle_cpumask_node(node) \ > + (bpf_ksym_exists(scx_bpf_get_idle_cpumask_node) ? \ > + scx_bpf_get_idle_cpumask_node(node) : \ > + scx_bpf_get_idle_cpumask()) \ > + > +#define __COMPAT_scx_bpf_get_idle_smtmask_node(node) \ > + (bpf_ksym_exists(scx_bpf_get_idle_smtmask_node) ? \ > + scx_bpf_get_idle_smtmask_node(node) : \ > + scx_bpf_get_idle_smtmask()) > + > +#define __COMPAT_scx_bpf_pick_idle_cpu_node(cpus_allowed, node, flags) \ > + (bpf_ksym_exists(scx_bpf_pick_idle_cpu_node) ? \ > + scx_bpf_pick_idle_cpu_node(cpus_allowed, node, flags) : \ > + scx_bpf_pick_idle_cpu(cpus_allowed, flags)) Can you please document when these compat macros can be dropped? Also, shouldn't it also provide a compat macro for the new ops flag using __COMPAT_ENUM_OR_ZERO()? Otherwise, trying to load new binary using the new flag on an older kernel will fail, right? Thanks. -- tejun