From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Elsayed Subject: Bcache data layout - suited as swap filesystem on SSDs? Date: Fri, 08 Mar 2013 22:52:02 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit Return-path: Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org I came across a paper [1] today talking about improving the Linux swap system for use on SSDs, and I realized that some points made in the paper could be addressed by using bcache 'in reverse', where instead of caching a slower block device it stores pages on behalf of faster memory. Bcache already optimizes for SSDs by writing linearly where possible, using 'buckets' sized to work well with eraseblocks, and taking advantage of high random read performance. The paper advocates doing much the same with swap on SSDs, although it also talks about removing layers of software between the VM and the SSD. Since bcache is an efficient way of storing sparse, fixed-size chunks of data identified by addresses, it might be a really interesting data layout for efficient swap on SSDs. [1] http://pages.cs.wisc.edu/~msaxena/FlashVMpaper.html