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c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745482268; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/XklnL33mAqjfgTc8xOBHGB4/KdOSZM8qUFg0CXXjsY=; b=O38CuYrVirhwCi8wssNlpDtj7fpgUCaY0oMRCm1g14iqKkDoGXK8blNpS+RmMzYiT2O2q7 L9gHVFJVaIN/Tmqj3GwwNoJE6muiywjuMxJlJTmVa9ig1jXTYa9RO8KA99hfxIxJIM4NRS HuOCty2lH40KdXfQevLw0Ae6lvquyBA= Received: by verein.lst.de (Postfix, from userid 2407) id 2F45667373; Thu, 24 Apr 2025 10:11:01 +0200 (CEST) Date: Thu, 24 Apr 2025 10:11:01 +0200 From: Christoph Hellwig To: Leon Romanovsky Cc: Jason Gunthorpe , Mika =?iso-8859-1?Q?Penttil=E4?= , Marek Szyprowski , Jens Axboe , Christoph Hellwig , Keith Busch , Jake Edge , Jonathan Corbet , Zhu Yanjun , Robin Murphy , Joerg Roedel , Will Deacon , Sagi Grimberg , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , =?iso-8859-1?B?Suly9G1l?= Glisse , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Niklas Schnelle , Chuck Lever , Luis Chamberlain , Matthew Wilcox , Dan Williams , Kanchan Joshi , Chaitanya Kulkarni Subject: Re: [PATCH v9 10/24] mm/hmm: let users to tag specific PFN with DMA mapped bit Message-ID: <20250424081101.GA22989@lst.de> References: <0a7c1e06269eee12ff8912fe0da4b7692081fcde.1745394536.git.leon@kernel.org> <7185c055-fc9e-4510-a9bf-6245673f2f92@redhat.com> <20250423181706.GT1213339@ziepe.ca> <36891b0e-d5fa-4cf8-a181-599a20af1da3@redhat.com> <20250423233335.GW1213339@ziepe.ca> <20250424080744.GP48485@unreal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250424080744.GP48485@unreal> User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Queue-Id: 216631A0006 X-Stat-Signature: 3hx9f1kmwarxod5npeq7u4ic1bb6qk3g X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1745482267-816127 X-HE-Meta: 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 vVo2kOx+ +qz5diWdAsB13wnnHD0B94yCDNW4PEABAsbwnmBuarjIDj9m/GG1Q0N7mE2kgHOlHJ1fV8B/NjJMamsQnovhEbW9gXM5wbjLn/DP0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Apr 24, 2025 at 11:07:44AM +0300, Leon Romanovsky wrote: > > I see, so yes order occupies 5 bits [-4,-5,-6,-7,-8] and the > > DMA_MAPPED overlaps, it should be 9 not 7 because of the backwardness. > > Thanks for the fix. Maybe we can use the chance to make the scheme less fragile? i.e. put flags in the high bits and derive the first valid bit from the pfn order?