From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 466BA6B025F for ; Fri, 11 Aug 2017 14:04:51 -0400 (EDT) Received: by mail-pg0-f70.google.com with SMTP id a186so44193604pge.7 for ; Fri, 11 Aug 2017 11:04:51 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id t12si847101plm.964.2017.08.11.11.04.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 11 Aug 2017 11:04:48 -0700 (PDT) Date: Fri, 11 Aug 2017 11:04:47 -0700 From: Christoph Hellwig Subject: Re: How can we share page cache pages for reflinked files? Message-ID: <20170811180447.GA23669@infradead.org> References: <20170810042849.GK21024@dastard> <20170810161159.GI31390@bombadil.infradead.org> <20170811042519.GS21024@dastard> <20170811170847.GK31390@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170811170847.GK31390@bombadil.infradead.org> Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: Dave Chinner , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org On Fri, Aug 11, 2017 at 10:08:47AM -0700, Matthew Wilcox wrote: > Assuming there's something fun we can do with filesystems that's > interesting to this type of user, what do you think to this: > > Create a block device (maybe it's a loop device, maybe it's dm-raid0) > which supports DAX and uses the page cache to cache the physical pages > of the block device it's fronting. Why not make every block device just support fake DAX and avoid the additional layer? Basically this would be going back to a file cache indexed by physical blocks from our logically indexed page cache model. And for a fs using heavy reflinks that's probably the right model in the end. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org