From: Randy Dunlap <rdunlap@infradead.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
akpm@linux-foundation.org,
Dan Williams <dan.j.williams@intel.com>,
Oliver <oohall@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 2/2] mm/pmem: Add memblock based e820 platform driver
Date: Fri, 6 Jul 2018 11:46:48 -0700 [thread overview]
Message-ID: <0a28ed01-fc76-0f08-3f8a-c2dd7f5fcd2f@infradead.org> (raw)
In-Reply-To: <20180706082911.13405-2-aneesh.kumar@linux.ibm.com>
On 07/06/18 01:29, Aneesh Kumar K.V wrote:
> This patch steal system RAM and use that to emulate pmem device using the
> e820 platform driver.
>
> This adds a new kernel command line 'pmemmap' which takes the format <size[KMG]>
> to allocate memory early in the boot. This memory is later registered as
> persistent memory range.
>
> Based on original patch from Oliver OHalloran <oliveroh@au1.ibm.com>
>
> Not-Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
> drivers/nvdimm/Kconfig | 13 ++++
> drivers/nvdimm/Makefile | 1 +
> drivers/nvdimm/memblockpmem.c | 115 ++++++++++++++++++++++++++++++++++
> 3 files changed, 129 insertions(+)
> create mode 100644 drivers/nvdimm/memblockpmem.c
>
> diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
> index 50d2a33de441..cbbbcbd4506b 100644
> --- a/drivers/nvdimm/Kconfig
> +++ b/drivers/nvdimm/Kconfig
> @@ -115,4 +115,17 @@ config OF_PMEM
> config PMEM_PLATFORM_DEVICE
> bool
>
> +config MEMBLOCK_PMEM
> + bool "pmemmap= parameter support"
> + default y
> + depends on HAVE_MEMBLOCK
> + select PMEM_PLATFORM_DEVICE
> + help
> + Add support for the pmemmap= kernel command line parameter. This is similar
> + to the memmap= parameter available on ACPI platforms, but it uses generic
> + kernel facilities (the memblock allocator) to reserve memory rather than adding
> + to the e820 table.
> +
> + Select Y if unsure.
> +
> endif
There's a high barrier for "default y", something like if the platform or device
cannot boot without it, it can be "default y". I have doubts that this is OK.
--
~Randy
next prev parent reply other threads:[~2018-07-06 18:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 8:29 [RFC PATCH 1/2] mm/nvidmm: Drop x86 dependency on nvdimm e820 device Aneesh Kumar K.V
2018-07-06 8:29 ` [RFC PATCH 2/2] mm/pmem: Add memblock based e820 platform driver Aneesh Kumar K.V
2018-07-06 18:46 ` Randy Dunlap [this message]
2018-07-06 19:38 ` Dan Williams
2018-07-07 7:15 ` Oliver
2018-07-07 17:36 ` Dan Williams
2018-07-09 5:17 ` Aneesh Kumar K.V
2018-07-09 6:06 ` Dan Williams
2018-07-07 7:50 ` Oliver
2018-07-09 5:16 ` Aneesh Kumar K.V
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