From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH V2 10/17] xprtrdma: Add CONFIG setting that can disable ALLPHYSICAL Date: Wed, 23 Apr 2014 13:24:35 +0300 Message-ID: <535794E3.1020201@dev.mellanox.co.il> References: <20140421214442.12569.8950.stgit@manet.1015granger.net> <20140421220214.12569.23157.stgit@manet.1015granger.net> <20140422062338.GA23311@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140422062338.GA23311-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christoph Hellwig , Chuck Lever Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org On 4/22/2014 9:23 AM, Christoph Hellwig wrote: > On Mon, Apr 21, 2014 at 06:02:14PM -0400, Chuck Lever wrote: >> ALLPHYSICAL is not a safe memory registration mode because it >> permits NFS servers to write anywhere in a client's memory. NFS >> server bugs could result in client memory being overwritten. >> >> This can be useful for embedded systems which do not support more >> surgical RDMA memory registration and protection methods, or for >> bring-up of new HCA hardware. >> >> However, enterprise Linux distributions have expressed a desire to >> disable it in production environments. > It's just as unsafe in embedded devices. I think it should go For small IOs pattern, ALLPHYSICAL should outperform any registration method in terms of IOP rate (simply because it doesn't do it). Generally speaking, deployments that may prefer higher IOP rate in the cost of a security do exist out there... Sagi. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html