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[91.12.108.214]) by smtp.gmail.com with ESMTPSA id c13sm39482052wrt.114.2022.01.05.00.46.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 05 Jan 2022 00:46:06 -0800 (PST) Message-ID: <93a8e489-5ca5-7593-5d2b-59280187e2a1@redhat.com> Date: Wed, 5 Jan 2022 09:46:05 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: remove Xen tmem leftovers To: Juergen Gross , Christoph Hellwig , Andrew Morton , Konrad Rzeszutek Wilk Cc: Hugh Dickins , Seth Jennings , Dan Streetman , Vitaly Wool , Matthew Wilcox , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20211224062246.1258487-1-hch@lst.de> <10ec73d4-6658-4f60-abe1-84ece53ca373@redhat.com> <82dbdc2c-20c2-d69b-bdc9-efc54939d54c@suse.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <82dbdc2c-20c2-d69b-bdc9-efc54939d54c@suse.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 6AF3AA000A X-Stat-Signature: kwrksgba4s3swukqunewy1f9iq55ywcj Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=bPrKDHyw; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf25.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com X-HE-Tag: 1641372352-37541 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: On 05.01.22 07:08, Juergen Gross wrote: > On 04.01.22 15:31, David Hildenbrand wrote: >> On 24.12.21 07:22, Christoph Hellwig wrote: >>> Hi all, >>> >>> since the remove of the Xen tmem driver in 2019, the cleancache hooks are >>> entirely unused, as are large parts of frontswap. This series against >>> linux-next (with the folio changes included) removes cleancaches, and cuts >>> down frontswap to the bits actually used by zswap. >>> >> >> Just out of curiosity, why was tmem removed from Linux (or even Xen?). >> Do you have any information? > > tmem never made it past the "experimental" state in the Xen hypervisor. > Its implementation had some significant security flaws, there was no > maintainer left, and nobody stepped up to address those issues. > > As a result tmem was removed from Xen. Interesting, thanks for sharing. I know tmem mostly from the papers and thought it was an interesting approach in general. There was even papers about a virtio implementation, however, actual code never appeared in the wild :) -- Thanks, David / dhildenb