RE: [PATCH 2/3] x86: add a is_e820_ram() helper

From: "Elliott, Robert (Server Storage)" <Elliott@hp.com>
To: Christoph Hellwig <hch@lst.de>, Boaz Harrosh <boaz@plexistor.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	"linux-nvdimm@ml01.01.org" <linux-nvdimm@ml01.01.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"Kani, Toshimitsu" <toshi.kani@hp.com>
Subject: RE: [PATCH 2/3] x86: add a is_e820_ram() helper
Date: Thu, 26 Mar 2015 18:46:07 +0000	[thread overview]
Message-ID: <94D0CD8314A33A4D9D801C0FE68B40295A84640D@G9W0745.americas.hpqcorp.net> (raw)
In-Reply-To: <20150326164314.GB23958@lst.de>

> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
> owner@vger.kernel.org] On Behalf Of Christoph Hellwig
> Sent: Thursday, March 26, 2015 11:43 AM
> To: Boaz Harrosh
> 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
> Subject: Re: [PATCH 2/3] x86: add a is_e820_ram() helper
> 
> 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.

I agree with Boaz that ! is a nuisance if loading pmem as a module
with modprobe from bash. 

The ! does work fine in the grub2 command line if the driver is 
built-in.  I added it to /etc/default/grub like this:
    GRUB_CMDLINE_LINUX="<other parameters> memmap=8G!18G"
and grub-mkconfig placed it in /boot/efi/EFI/centos/grub.cfg
with no issues.