From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6B97ECA5FDD for ; Fri, 2 Oct 2026 15:34:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BBvnzeVp5FHZbtbBZ742DHLscz+VvjPcvOwODIGv8pw=; b=acsGvpVZHKewCYnLlVEtGL5c7u svPlgRdlOT2JmrWq6dFtuKHvJpc5VUa51ZAlUBXRMrwx1UWbopXUAYFXfWjhitiYpWKiMUJQwh5UO 689cE6UCvxApuWZLvI9ZLkc/0DSIpBVRRznX0B+WRfQT1OzhNz1UBuEUzsSwoMDUQ2Hg5Z23/xbt2 4UnMFHMY+E5smr34RxC6l2X/a3y9YzRCzx/67AVEpuQwOHzYtsi9UqKEPucylz6AicuOWguBB37WY QRwRkpcbF997Z59ubvcEImrYZAiuvuCj5BIZmVYi3RdicNJj2F8vPhP+lOT8tMLeAWRPDxb9ATUqa C0ocm/5g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCfGs-0000000BwD2-0vnq; Fri, 02 Oct 2026 15:34:02 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCfGq-0000000BwCT-3ytV for linux-arm-kernel@lists.infradead.org; Fri, 02 Oct 2026 15:34:01 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 25D4B60A8C; Fri, 2 Oct 2026 15:34:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B48C1F000FF; Fri, 2 Oct 2026 15:33:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790955239; bh=BBvnzeVp5FHZbtbBZ742DHLscz+VvjPcvOwODIGv8pw=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=XWjFqyFh/EG972dwRFuGfXIxWJ8hldbJMvx9UV/6AREZaqE4lrtN1YXaUywZDdaHD Q2ZSH1eValsjSi+u84xNA3G4wHT8ZIfkCn49rQGHxQr4e3hpQOeqgPeu4agZj0xzJg LnJfRYjxBg/69Q8uhAeq13pk6Y1s8Al917oAsW3aN/WtN4MOKF3rlipnT/iHgIoe2p q+fuaNEtlo66Zx3gwEpj8AzbX0Lp+taf+9dhW7icW5HjQc9k7MXS9JgDI7oto7usjE RE+BzBk0gMlrnYIPp5M783xe34Yvwl73O/IWpIzpaQDIJdWPWaNWtufA+4PgCf8tYd FQvTq59FnAg5w== Date: Fri, 2 Oct 2026 16:33:52 +0100 From: Will Deacon To: Kiryl Shutsemau Cc: Jason Gunthorpe , Robin Murphy , Joerg Roedel , Nicolin Chen , Pranjal Shrivastava , Mostafa Saleh , Thierry Reding , Krishna Reddy , Jonathan Hunter , Breno Leitao , Kyle McMartin , Usama Arif , kernel-team@meta.com, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 1/2] iommu/arm-smmu-v3: Add a cmdq_max_n_shift module parameter Message-ID: References: <20260909095228.2174031-1-kas@kernel.org> <20260909095228.2174031-2-kas@kernel.org> <179018301689.3334538.1783583175230817305.b4-review@b4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 25, 2026 at 11:01:31AM +0100, Kiryl Shutsemau wrote: > On Wed, Sep 23, 2026 at 02:03:36PM -0300, Jason Gunthorpe wrote: > > > [ ... 34 lines skipped ... ] > > > @@ -40,6 +40,11 @@ module_param(disable_msipolling, bool, 0444); > > > MODULE_PARM_DESC(disable_msipolling, > > > "Disable MSI-based polling for CMD_SYNC completion."); > > > > > > +static unsigned int cmdq_max_n_shift; > > > +module_param(cmdq_max_n_shift, uint, 0444); > > > +MODULE_PARM_DESC(cmdq_max_n_shift, > > > + "Cap on the command queue depth, as log2 of the number of entries. Zero means the hardware maximum; the queue never shrinks below one page."); > > > > The patch looks ok > > > > Reviewed-by: Jason Gunthorpe > > > > But I'd rather use lg2 as name, especially user visible, instead of > > n_shift. "shift" is a word for bitwise stuff, this is a 2**N log2 > > encoded value. > > This name has changed twice already. v5 took the value in entries. > Nicolin asked for a log2 value and named it after max_n_shift, which is > what the driver calls this quantity everywhere else. > > I would rather not rename it a third time without input from the > maintainer. > > Will, this is the user-visible name. Do you have a preference here? > Unless you want it changed I will leave v6 as it is. I don't have really strong opinions on naming, but since Jason has given a reasonably complete outline of the change and I have a small preference for the lg2-style naming (rather than exposing the name of an internal driver variable), it would be great if you can spin a v7 with that included so that I can pick it up. Thanks, Will