From: Christoph Hellwig Subject: Re: [PATCH 2/3] x86: add a is_e820_ram() helper Date: Thu, 26 Mar 2015 17:43:14 +0100 Message-ID: <20150326164314.GB23958@lst.de> References: <1427358764-6126-1-git-send-email-hch@lst.de> <1427358764-6126-3-git-send-email-hch@lst.de> <20150326090215.GA11520@gmail.com> <20150326093424.GA28217@lst.de> <55142A92.4060607@plexistor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , Ingo Molnar , linux-nvdimm@ml01.01.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, ross.zwisler@linux.intel.com, axboe@kernel.dk To: Boaz Harrosh Return-path: Content-Disposition: inline In-Reply-To: <55142A92.4060607@plexistor.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, Mar 26, 2015 at 05:49:38PM +0200, Boaz Harrosh wrote: > > + memmap=nn[KMG]!ss[KMG] > > + [KNL,X86] Mark specific memory as protected. > > + Region of memory to be used, from ss to ss+nn. > > + The memory region may be marked as e820 type 12 (0xc) > > + and is NVDIMM or ADR memory. > > + > > Do we need to escape "\!" this character on grub command line ? It might > help to note that. I did like the original "|" BTW No need to escape it on the kvm command line, which is where I tested this flag only so far. If there is a strong argument for "|" I'm happy to change it. > > +#define E820_PRAM 12 > > Why the PRAM Name. For one 2/3 of this patch say PMEM the Kconfig > to enable is _PMEM_, the driver stack that gets loaded is pmem, > so PRAM is unexpected. > > Also I do believe PRAM is not the correct name. Yes NvDIMMs are RAM, > but there are other not RAM technologies that can be supported exactly > the same way. > MEM is a more general name meaning "on the memory bus". I think. > > I would love the consistency. Ingo asked for the PRAM name, I don't really care either way. > > + case E820_PRAM: > > + printk(KERN_CONT "persistent (type %u)", type); > > This case can only mean 12 in this patch. (I think historically > you had a Kconfig to set its Number Indeed. I kept it in case people hack their kernels, but I can remove it if people feel it's too ugly.