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[142.134.23.187]) by smtp.gmail.com with ESMTPSA id y1-20020a056870a34100b001f949c5a757sm220261oak.38.2023.11.20.06.46.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Nov 2023 06:46:05 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1r55XI-000bho-Hg; Mon, 20 Nov 2023 10:46:04 -0400 Date: Mon, 20 Nov 2023 10:46:04 -0400 From: Jason Gunthorpe To: Boris Brezillon Cc: Joerg Roedel , iommu@lists.linux.dev, Will Deacon , Robin Murphy , linux-arm-kernel@lists.infradead.org, Rob Clark , Gaurav Kohli , Steven Price Subject: Re: [PATCH v2 0/2] iommu: Allow passing custom allocators to pgtable drivers Message-ID: <20231120144604.GD10140@ziepe.ca> References: <20231110094352.565347-1-boris.brezillon@collabora.com> <20231110151428.GJ4634@ziepe.ca> <20231110164809.270f82bc@collabora.com> <20231110161229.GA462657@nvidia.com> <20231110201652.629b7228@collabora.com> <20231110194215.GR4488@nvidia.com> <20231113101103.1cc05c8c@collabora.com> <20231120140425.GA10140@ziepe.ca> <20231120153838.2166e7b8@collabora.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231120153838.2166e7b8@collabora.com> On Mon, Nov 20, 2023 at 03:38:38PM +0100, Boris Brezillon wrote: > > At LPC there was quite a lot if interest in improving the io page > > table stuff to work better. Based on that I'm even more against adding > > an external allocator at this time. :\ > > I'm sure this has been discussed with the IOMMU maintainers, but I'd > really like to hear it from them if you don't mind. Especially since, > as I mentioned, the custom allocator idea comes from Robin, not me... It is a community effort - this is my opinion. We now understand this io page table area needs a lot of work to meet all the new needs. I'm against hacking it up like this and making that work harder. > v1, was a sign this was good to go. If the final call is to reject the > custom allocator approach, and there's no updates on your generic > solution in the next couple weeks, I'll probably copy the pgtable code > in panthor so I can implement my own stuff, and later switch back to > the generic io-pgtable implementation when things have settled down. That's horrible, DRM should refuse that too, yet I expect you will probably end up merging like that. I would not expect a resolution in a few weeks. > Nothing against you or your solution (I actually commit to move to the > new approach when it's ready), but we have different priorities, and I > can't really delay the driver merging by several months unless there's > a very good reason to do it. Welcome to Linux, nothing runs fast :( Jason