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 825E5C7EE2A for ; Fri, 27 Jun 2025 16:27:10 +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=W9L9/2IlH59KoNo72ZuQrbZj7UjOO0RlgNZjx5UyK5g=; b=g7c2nRX5ra5O9FRBWlDe6uzYuQ fCkjyhw+Cdvcv2dP/Pk2izZ+9wfpEGjNWq2kG9Fta6LaA8J1VJ/Ys8NiCdKHaA2dUlWalecNMB7Kx iMQ+tbX8eabpHJGhGeOMUeXEaqTa5kpAjc7yuDqhgcn/j1ks1xaXpScgtkPD09XfzmKhjfSEVJ2xx ZO9ZTa7UmaFR+YfrmJgM418DQ542vamjkB0XpDyA7Zy9THTqCdAGQhMvZrbtha8wHW+17v+JDcQdr UFfh77KZgYrrn41q7r1dv3EzZ4bk7o4ow61fT5DSB2dY0SMcjXnmZ0pT3WDPoDHiTUuIzImHBNuUV i5kTvAPg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uVBus-0000000FGEF-3LRi; Fri, 27 Jun 2025 16:27:06 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uVB6R-0000000F7aL-0yxI for linux-nvme@lists.infradead.org; Fri, 27 Jun 2025 15:34:59 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 808966111F; Fri, 27 Jun 2025 15:34:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02B07C4CEE3; Fri, 27 Jun 2025 15:34:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751038498; bh=eV6UPyQupWZyH5CaGFeLs90y5amWd+ZIXGdb67QPlxQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mLuB8QYEFqRyLJS8HKGoRgjB2EowyBRr4EuqbaKc6MT2bBf7yOhJ3kLLJaInZstfs Uh8J+xqL+zx20WQCuBEuSeUKnpwmPi5mysG01vsM3ZwLUUQr3GQSYr5vyeY3G6z1Te aQDQIGDfe0RF1hnEfhPsFEVHPybzFQv7kvh1j5o21u2UTYRkgObGJl6xYBR1bhnqS1 da5ZT1uE0utKHnmpgpS8PH+SK8iln9aHFJw/oUlGQcmsh0l23u1HVg7gHZiKjb5/Mz qTb/qCR2gc2qdCJ9QN+RhXlp/oy+Q/cM+fAaaJ7Y/I9BW36KXSr4rwgBXIu9gYFb43 KP0Drr86fnBgQ== Date: Fri, 27 Jun 2025 09:34:56 -0600 From: Keith Busch To: Christoph Hellwig Cc: Keith Busch , linux-nvme@lists.infradead.org Subject: Re: [PATCH] nvme: uring_cmd specific request_queue for SGLs Message-ID: References: <20250624211444.2835077-1-kbusch@meta.com> <20250625060915.GB9391@lst.de> <20250626051413.GC23248@lst.de> <20250627072524.GA1329@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250627072524.GA1329@lst.de> X-BeenThere: linux-nvme@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-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Jun 27, 2025 at 09:25:24AM +0200, Christoph Hellwig wrote: > > Oh, you are referring to blk_dma_map_direct? Yes, exactly. Sorry I shortened the name to the ambiguous "direct", but I think we're on the same page now. Back to this patch, I get that this uring_cmd path wouldn't be able to use the more efficient coalesced mapping when the IOMMU is on, and instead map each segment indiviually. I think that's still better than the alternative, though.