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 F039D20AF66 for ; Fri, 11 Apr 2025 11:08:15 +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=1744369697; cv=none; b=Slp4TV32mQpcsQEGZkuHvhAN20i0fEmDNgOGmq8CvT2XpMGGXDe/aglbnqALBxSZmdePb1RsdMlX0XZKnK4TMIdNXTdTvHGYPuUd/UkFoYQQxYY6JT+mLQXzR1FMkxothW1MrdH+bkAdoXaF8XUGE+FFjagvv4BHyDB4x567xzA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744369697; c=relaxed/simple; bh=XnWf18T4aDc2xmNps0it2JLrQ9AKau7dBuKwdDKj6zE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kPKh2eLLa/pC8lqm+DdZaBpidh24PRMOgS2gf4wiAX2ES5eI8E70Bj/AXHvWLgq2qXGLvT927f3kximGJ0cxxjEyxgn2fChSNzMXHDRDNHILTNiI9Ap7yvUn3oDz/dnoINHPePdKTw28j6LZQ3Y6RBABCGOH3fUSdTAs9DNPFxU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dyGoBPYB; 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="dyGoBPYB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF32BC4CEEA; Fri, 11 Apr 2025 11:08:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744369695; bh=XnWf18T4aDc2xmNps0it2JLrQ9AKau7dBuKwdDKj6zE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dyGoBPYBNvz7vzJ1/ucwrebmsgt1MrVYBzyUbG6S/gx4cA5hYAGFVNGIMXrewXIiY wmCKjFCDUliOvMo+AXMElY9iaxEL61dHP5lMYU/adTVxXjvk9hqqThiB367HNQ3hgK XReqfvhwqX2kFdrpSDeMhJnmqetg8qQQhZ9V33sxpLOXOZ6nhgSBU2Hu1IxoGO7Bi2 JOaNeCYWiH2qfg9W4mwSQeSQOXCLuYq99P6x/XwXf5IPHql1xWRFN2ezVWaLdpKggm OjO5zQnKHBScQqMErg4QOI74gzO+kOARfI40m1n177cLW51RdLkGLsDrhoI6t3w9oX 54ITeqWvlxJcg== Date: Fri, 11 Apr 2025 13:08:12 +0200 From: Frederic Weisbecker To: Alex Shi Cc: alexs@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Waiman Long Subject: Re: [PATCH 2/4] sched/isolation: clean up housekeeping_cpu Message-ID: References: <20250410092423.9831-1-alexs@kernel.org> <20250410092423.9831-2-alexs@kernel.org> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Le Fri, Apr 11, 2025 at 08:58:45AM +0800, Alex Shi a écrit : > Frederic Weisbecker 于2025年4月10日周四 21:20写道： > > > > Le Thu, Apr 10, 2025 at 05:24:17PM +0800, alexs@kernel.org a écrit : > > > From: Alex Shi > > > > > > housekeeping_test_cpu will check 'housekeeping_overridden' again in > > > itself so we don't need do it again outside. just call > > > housekeeping_test_cpu is fine. > > > > The point is to do it in the headers, so there is no function > > call in the off case. > > Thanks for comments, Frederic, > But the function is 'inline', and further more, the > CONFIG_CPU_ISOLATION is in defconfig > and most of puplar popular Linux vendor. So it still be compiled. housekeeping_cpu() is inline and does the static branch test, which is most of the time off. If it's on, then we enter the slow path and call the real function housekeeping_test_cpu(). So the point is to optimize the fast path, which 99.999% of the uses since nohz_full is a rare workload. But housekeeping_test_cpu() is still built on most distros just in case a distro user ever needs nohz_full. Thanks. -- Frederic Weisbecker SUSE Labs