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 291FD471CF3; Fri, 21 Aug 2026 10:53:13 +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=1787309596; cv=none; b=gTWLGnGWc1GRiIR9J3hIAf/4I8MaqX57cvWvTmlCx1hbEAIqPKR1/2MgQ4x16tWa0GS+RrCJeltMh+dn4HaAcbRuyQJA7ILfQcWDBMbZLLyNE6Y7n2VgsDWkfYXH0bPMkZD03O8fsjhkZCRD3KWVQU6doHyy75R72EUYfbnbgAM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787309596; c=relaxed/simple; bh=db9tvE++slmSkBi47GlKRkGxKG6uu119fd5Trvcau+c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mNE/7OZaKCc+lqXbopTcmNE5uxzngPHCeuw0MNNatweARFhgA1mvYVlgnLn19gt8QoCfl5zfff1KNmEejTfgvtLKnrThW/CCdmjofCG4gAOsWnYEKBou8rhMKuQd2NvHl5pWt5HfAbrx2ow5O4UT/XqHBtf4RA2BuVLlOuiNLPw= 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=sm+SplkN; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=4d50prHH; 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="sm+SplkN"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="4d50prHH" Date: Fri, 21 Aug 2026 12:53:10 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1787309591; 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: in-reply-to:in-reply-to:references:references; bh=XOfj9iWnujkJXGCKkSSLRpyruq4aYxWH0TC7ipj0KRA=; b=sm+SplkNZFrICX9Fb0x5cjvPTX1Nl43EIl5/jxIR8+H/Ke9ZRXCd+ZHXX2mFhfFV112VOR mIrG9UoLse0L+L/A4T5ZDTAhUY1olw0NBYiKXRCC1yQ6JVHChCsE1QtT3V92ABG3gwAX5B sHXuB/ytWthEyT+8WDmPoTsl2Y+mXBFhsA0BfKayGRBy1YP9s7X4mvflbzxC3Xw2KCSrpe xjOslBkfF2qeUfsFwTe2EsSUWIHs7gJSNOaP17sDQTVjfiQMvQ0X1DIKbXiREPzhEkgbZG 5JGdMmYLXwNfEJy6EcfSVX5OcGVmwRXfISpLWyUHmxfQ+o4EaTZ881Wus2MmwA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1787309591; 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: in-reply-to:in-reply-to:references:references; bh=XOfj9iWnujkJXGCKkSSLRpyruq4aYxWH0TC7ipj0KRA=; b=4d50prHHZbcMsOnjLv+aq7L6GtmqE62MkA8FN7P6Pd/xcbYtjFbFbWZZ4hi/ZD3dhty1Z/ ixTUDOIrkQ46E0Cw== From: Sebastian Andrzej Siewior To: Jan Kiszka Cc: Jakub Kicinski , Florian Bezdeka , Maxime Chevallier , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , Maxime Coquelin , Alexandre Torgue , Yury Norov , Rasmus Villemoes , Andrew Morton , Clark Williams , Steven Rostedt , Thomas Gleixner , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH RFC 2/3] genirq: Honor existing IRQ affinities when setting affinity hints Message-ID: <20260821105310.ZRK2TO93@linutronix.de> References: <20260819-flo-net-7-2-make-stmmac-default-affinity-aware-v1-0-3f79a99cadaf@siemens.com> <20260819-flo-net-7-2-make-stmmac-default-affinity-aware-v1-2-3f79a99cadaf@siemens.com> <20260820094153.420202f6@kernel.org> <11c2d3c4-ea05-46a2-8579-c5aba1bfa204@siemens.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=utf-8 Content-Disposition: inline In-Reply-To: <11c2d3c4-ea05-46a2-8579-c5aba1bfa204@siemens.com> On 2026-08-21 12:38:52 [+0200], Jan Kiszka wrote: > Fully agree: drivers should not set affinities. They should just express > desires or additional constraints. The ultimately resulting affinity for > an IRQ should be the result of the various constraints that kernel and > userland may express via NUMA placements, isolcpus, some dynamic > isolation/grouping constraints, or you-name-it. You might want to look at irq_create_affinity_masks()/ group_cpus_evenly() which attempts to spread irqs evenly across CPUs/ NUMA nodes. This is used by storage is considered a bit by the isolcpus=managed_irq option. > I think we need a big picture how things should eventually look like and > then develop a strategy how to step-wise convert existing code. > > Jan Sebastian