From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6D819475351 for ; Wed, 14 Oct 2026 21:39:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792013962; cv=none; b=Bc96r0uDwGy/wQNlbjTgW267dxA3vQs2wD1Mbt4uz8BAR3ShAA5mTcjRFHmz1lRGPyZdK/WTSZ3LVICjU1KvBGCphf3g0kkKtc6vcWtB/rxzcB7Atzg1Fkrph8g8fezZw7KNxadlk+d6XfR4gWonh6oWIICzxyJHwQ1TsWmskQU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792013962; c=relaxed/simple; bh=YZ3USTerO1KVZxlzLH4WWR1OpRpRgNIFQgLPolE8aXw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ekcIsG0JzlCr6iVHbt7fTuC+GKLOCFgnerImCBq8eoncQH6kRlwX/u3hL8+ja7NVBFfVB0w/B9nXNAnOuoO0A7LttuSHkE5E8DyBzE/l7jMV48dHW0PbXiOt/BnxXyXdYwPe/KeRPNJTiFVy8c45wcQFMJvG09nVdA+Y2+1Qo+w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HRCHauSg; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HRCHauSg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CD451F000C4; Wed, 14 Oct 2026 21:39:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792013960; bh=yfZ/FsY5Zh5zIE98xQp6NV9qIckj8O0+XPOxXg+eC7s=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=HRCHauSgwJ/+0LsfAw1SACphQ9Kn9zODj961nCBEGV3/bMZDtKsi2rGRhU7tDMSC4 zXjZTwx6P3bv7dM2sLbW2w2Eu4X7AWVVRSN70mffrQhpCfaBRUhmzmrBnnq1UT3Ad+ sdFqv9lK/4YPubDzF1ZBrTc4iBwKBQVkEhtitkdWCDGeWsoygSExU1/8B8ATIw7fi2 OcjPxIKmVDBMwpeteOneHvhiUVdJcfLqy/A0HC+I0GH7C01JiQvD52c9C2IldfJ8DF 0gK1udx+3M2MAvlbMnvEQqvlFvz68IgsgdXakWqQqMasBApPcyiFKfRnEYjFQvAYVT g1auJ3Fe/9Uow== Date: Wed, 14 Oct 2026 15:39:18 -0600 From: Keith Busch To: Thomas Gleixner Cc: Bjorn Helgaas , Keith Busch , linux-nvme@lists.infradead.org, hch@lst.de, changfengnan@bytedance.com, linux-pci@vger.kernel.org, namjain@linux.microsoft.com, Luigi Rizzo Subject: Re: [RFC PATCH 2/3] PCI/MSI: Implement irq_mask_nowait() for MSI-x Message-ID: References: <20261014173106.GA1643226@bhelgaas> <878q40f0oa.ffs@fw13> Precedence: bulk X-Mailing-List: linux-pci@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: <878q40f0oa.ffs@fw13> On Wed, Oct 14, 2026 at 11:10:45PM +0200, Thomas Gleixner wrote: > On Wed, Oct 14 2026 at 12:31, Bjorn Helgaas wrote: > >> Skip the read-back that flushes the MSI-x mask write. Parent domains > >> that mask on behalf of PCI/MSI continue using their own irq_mask(). > >> > >> Signed-off-by: Keith Busch > > > > I assume Thomas will review/ack the pci/msi/ parts. > > Yes. I actually suggested that "nowait" mechanism to Keith at LPC. > > Though I hate the name of that callback because irq_mask() does not > really wait. It guarantees that the mask store has reached the device > which means that after that point no further interrupts will be sent by > the device (assuming sane hardware). That means it's a synchronous > operation which involves flushing the store, so maybe irq_mask_noflush() > or irq_mask_async() might be more accurate and descriptive. Right thank you, I misremembered your suggested name. I am totally fine with "noflush", and I've made that change in my local branch. I'll just wait a bit for any other feedback before the next version. > > Cc'd Luigi since I know he's interested in interrupt moderation in > > general. > > Correct. I'm curious whether the interrupt frequency based moderation > mechanism Luigi is proposing does solve the NVME issues as well or can > be combined with some device specific hint mechanism. > > That said, Luigi's approach should benefit from the "nowait" mechanism > as well. > > Luigi? > > Thanks, > > tglx