From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 A308C3233E8; Mon, 27 Apr 2026 15:07:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777302465; cv=none; b=gQOFUDK7JBpwKrry8ZCjwZwk/WLrrhB4gz0AjBb+m1dDSQsYtzTany7s1CRHvn58kn8qZSDa9OQJxq6bC8AytybiKNNfyxgd7ajSxnpIwwerP+Awurk6sKnISKTpYNoJnqbw82ilMYNNbrxET+0NehmCBkvf9JlMrvm1bkq82vA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777302465; c=relaxed/simple; bh=AQBxmjsjMhhbyqKfFr7H9MV/bPUCpy2HbZrxuKFDX0s=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=du9OmfhXIhmtcM/6ekKZ/I8o1lfOE8bsHqxolsx+BdYlfHwLpYcFGdLwvY8WVI6Gzq0h0OBhCZ+5oYQ446fuC5iqWlMCNSS2upju0JEYW0FowDm0YQ90vNpZ2L2G8kF0Xz4Do+piozEtzGF3Yq+DHJ0VFx7klXVL2MZlW28qY5M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=L97hAbzA; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=3gs6wQg2; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="L97hAbzA"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="3gs6wQg2" Date: Mon, 27 Apr 2026 17:07:39 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1777302461; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=TuSwYV0esKE1jACuhMi6TAI9cIJLaL1At8AYSskrutY=; b=L97hAbzA1IN7PymXEVNLpmW1MGj3uNH/0w0+F2nMCtikamwDRrYBX0zM6pM7xWrTn/bxfr wItHlJRvDX/VVS1OpOacL9M4uZltbe3Dm6ntHQUiUAVEgZXk5nOO7GJ4Ks8AEnNPjn73nB dQ4opEED4/KEpk/2tvXQvzvJlzpE8ZEdLXY6rUXzQwE/AsHf4ZA5AHVT1szPN1o9ruAIvG hHJ/jjXDtLNsSSy55agn82LmZcTAYKX/UWty7Q3Mak+1yax8hQjuYuK9Hm0Tk9FnvJi8wE U25/+ziq8W2QBY8rFbgJtDnRKHHuKGy4qxfwEwLG2Hv+CcK2v4sdU8EoioNzkw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1777302461; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=TuSwYV0esKE1jACuhMi6TAI9cIJLaL1At8AYSskrutY=; b=3gs6wQg2/UubVXyK0CTCxJGM33Mil8AWZUQYd1aEq8GrfWR+g2OUeqTig3j5RT9MkZXs/v bFuSyOcCJTaMpHBg== From: Sebastian Andrzej Siewior To: Frederic Weisbecker Cc: LKML , Gabriele Monaco , Ingo Molnar , Jonathan Corbet , Marcelo Tosatti , Marco Crivellari , Michal Hocko , "Paul E . McKenney" , Peter Zijlstra , Phil Auld , Steven Rostedt , Thomas Gleixner , Valentin Schneider , Vlastimil Babka , Waiman Long , linux-doc@vger.kernel.org, Bagas Sanjaya , Shuah Khan , John Ogness Subject: [PATCH] Documentation/kernel-parameters: Remove "Deprecated" from isolcpus= Message-ID: <20260427150739.bwVmmkj2@linutronix.de> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline The isolcpus= option has been marked as deprecated in 2017. Back then it was desired for the domain sub option to be configured dynamically at runtime instead using this boot command line which provides a static configuration. In the meantime this option was extended by other sub options which don't have runtime counterpart or it does not make sense to provide one. The deprecated part always referred to the default `domain' sub option but it was not obvious. Also the reasoning behind the deprecation is sort of dubious: There is nothing wrong with a static configuration if there is no desired to reconfigure. This is useful on systems which have one purpose and the CPU partition configuration is not changed for the entire lifetime. Remove the "Deprecated" note. Remove the part of the description which suggest to use cpuset.sched_load_balance and instead point to the documentation file which explains how to use cpusets to configure this at runtime. Signed-off-by: Sebastian Andrzej Siewior --- Documentation/admin-guide/kernel-parameters.txt | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 4d0f545fb3ec5..367931fe8da56 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2755,7 +2755,6 @@ Kernel parameters Format: ,,, isolcpus= [KNL,SMP,ISOL] Isolate a given set of CPUs from disturbance. - [Deprecated - use cpusets instead] Format: [flag-list,] Specify one or more CPUs to isolate from disturbances @@ -2780,11 +2779,10 @@ Kernel parameters Isolate from the general SMP balancing and scheduling algorithms. Note that performing domain isolation this way is irreversible: it's not possible to bring back a CPU to - the domains once isolated through isolcpus. It's strongly - advised to use cpusets instead to disable scheduler load - balancing through the "cpuset.sched_load_balance" file. - It offers a much more flexible interface where CPUs can - move in and out of an isolated set anytime. + the domains once isolated through this boot time + configuration. Use cpusets for a dynamic configuration + which can be altered at runtime. For details see + Documentation/admin-guide/cpu-isolation.rst. You can move a process onto or off an "isolated" CPU via the CPU affinity syscalls or cpuset. -- 2.53.0