From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 2 Mar 2016 09:14:26 -0500 From: Matthew Wilcox To: James Bottomley Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, lsf-pc@lists.linux-foundation.org Subject: Re: [Lsf-pc] [LSF/MM TOPIC] Support for 1GB THP Message-ID: <20160302141426.GM3730@linux.intel.com> References: <20160301070911.GD3730@linux.intel.com> <20160301102541.GD27666@quack.suse.cz> <20160301214403.GJ3730@linux.intel.com> <1456871764.2369.59.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1456871764.2369.59.camel@HansenPartnership.com> Sender: owner-linux-mm@kvack.org List-ID: On Tue, Mar 01, 2016 at 02:36:04PM -0800, James Bottomley wrote: > On Tue, 2016-03-01 at 16:44 -0500, Matthew Wilcox wrote: > > I think it's both. I heard from one customer who calculated that > > with a 6TB server, mapping every page into a process would take ~24MB > > of page tables. Multiply that by the 50,000 processes they expect to > > run on a server of that size consumes 1.2TB of DRAM. Using 1GB pages > > reduces that by a factor of 512, down to 2GB. > > This sounds a bit implausible: Well, that's the customer workload. They have terabytes of data, and they want to map all of it into all 50k processes. I know it's not how I use my machine, but that's customers for you ... -- 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