From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id E2FE91427A; Wed, 10 Jun 2026 06:14:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781072075; cv=none; b=V4iRIjH6BZ3ddl3JXwvgkRQ+XOpXDYG5lqNyLej+5T7j5gWYk0SHLwnZxo4OX4KajyCQBHqDJZslx4duUy3NvqAG5JfmfYgshIx66CeJVmaM/WYMLHb+23ab5Tuc5/4Qw/nXhT+7LztKZN8/+7aFzlh9Trotv+4T3smkMWbb+5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781072075; c=relaxed/simple; bh=hhh4XKG7ft2SZsK9eI6/SwHmVB16iLYuL8NzOKU4t5Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I0kIvaqq4xjHImUs/qZyWPOtgD/oiI+RY2yvFWW4w5jblw34ECM6VNvmTWbK2pqzCzSAG0Yidyfc9sYdXDei068IFZRUHKYseSh/dBPfE7878y7EK7Tra8bcYxEF1dXjOFofoMSuJY7pevzoblafH48qHXZj8YuS9zrdBGwtAlU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=OFImmvbh; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="OFImmvbh" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=5fpuLCYTLSfZqoqCj1yrU/fpNj0jEx06J2udbdGke8E=; b=OFImmvbhxqzG81oeZG+qkLiWj/ O+FoTgH6IsD9H6izBN+zbpqolbxqx+9PFaalE0ngf4ZPtIVhKG3FWNncNpUvassE+pMoxg7uJ1dlN o/1a+N0fBlbkrkKv2jfdrPPcrlf8nC1+BFWDS5uwfZXWKBQIW9aXC8ONxzWjN5GQqHnNRYbkZWGsc r9zOlolOC8eIVseUzidKJhPi3wTenh7FHIi9rxabyyO+h/40Pa5f3/VNUtd20iNePgabwc3S+cnjT Kd3X/a3mAFndB1a4zGa1uW8ACr+9Jp1LawQAr1tSl3VC1bdB13cQxeZxqMdPuJ1TIqqIwB6io6LeU cbljK5hw==; Received: from hch by bombadil.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXCCZ-00000006rUM-2is2; Wed, 10 Jun 2026 06:14:11 +0000 Date: Tue, 9 Jun 2026 23:14:11 -0700 From: Christoph Hellwig To: Sumit Saxena Cc: "Martin K . Petersen" , Jens Axboe , "James E . J . Bottomley" , linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, Adam Radford , Khalid Aziz , Adaptec OEM Raid Solutions , Matthew Wilcox , Hannes Reinecke , "Juergen E . Fischer" , Russell King , linux-arm-kernel@lists.infradead.org, Finn Thain , Michael Schmitz , Anil Gurumurthy , Sudarsana Kalluru , Oliver Neukum , Ali Akcaagac , Jamie Lenehan , Ram Vegesna , target-devel@vger.kernel.org, Bradley Grove , Satish Kharat , Sesidhar Baddela , Karan Tilak Kumar , Yihang Li , Don Brace , storagedev@microchip.com, HighPoint Linux Team , Tyrel Datwyler , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , linuxppc-dev@lists.ozlabs.org, Brian King , Lee Duncan , Chris Leech , Mike Christie , open-iscsi@googlegroups.com, Justin Tee , Paul Ely , Kashyap Desai , Shivasharan S , Chandrakanth Patil , megaraidlinux.pdl@broadcom.com, Sathya Prakash Veerichetty , Sreekanth Reddy , mpi3mr-linuxdrv.pdl@broadcom.com, Suganath Prabu Subramani , Ranjan Kumar , MPT-FusionLinux.pdl@broadcom.com, Daniel Palmer , GOTO Masanori , YOKOTA Hiroshi , Jack Wang , Geoff Levand , Michael Reed , Nilesh Javali , GR-QLogic-Storage-Upstream@marvell.com, Narsimhulu Musini , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , linux-hyperv@vger.kernel.org, "Michael S . Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Eugenio Perez , virtualization@lists.linux.dev, Vishal Bhakta , bcm-kernel-feedback-list@broadcom.com, Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , xen-devel@lists.xenproject.org, Bart Van Assche Subject: Re: [PATCH v3 3/4] block: drop shared-tag fairness throttling Message-ID: References: <20260609121806.2121755-1-sumit.saxena@broadcom.com> <20260609121806.2121755-4-sumit.saxena@broadcom.com> Precedence: bulk X-Mailing-List: linux-block@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: <20260609121806.2121755-4-sumit.saxena@broadcom.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Just dropping the fairness was rejected before and there is no explanation here on why any of that has changed. On Tue, Jun 09, 2026 at 05:48:02PM +0530, Sumit Saxena wrote: > From: Bart Van Assche > > Original patch [1] by Bart Van Assche; this version is rebased onto the > current tree. In testing it improves IOPS by roughly 16-18% by removing > the fair-sharing throttle on shared tag queues. > > This patch removes the following code and structure members: > - The function hctx_may_queue(). > - blk_mq_hw_ctx.nr_active and request_queue.nr_active_requests_shared_tags > and also all the code that modifies these two member variables. .. and besides that, this commit message is still entirely useless as it doesn't explain any of the thoughts of why this change is safe and desirable. While the mechanics above are totally obvious from the code change itself.