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From: Dave Hansen <dave.hansen@intel.com>
To: Yanmin Zhang <yanmin_zhang@linux.intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	dave@sr71.net
Cc: dan.j.williams@intel.com, dave.jiang@intel.com,
	zwisler@kernel.org, vishal.l.verma@intel.com,
	thomas.lendacky@amd.com, akpm@linux-foundation.org,
	mhocko@suse.com, linux-nvdimm@lists.01.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	ying.huang@intel.com, fengguang.wu@intel.com, bp@suse.de,
	bhelgaas@google.com, baiyaowei@cmss.chinamobile.com,
	tiwai@suse.de
Subject: Re: [PATCH 4/4] dax: "Hotplug" persistent memory for use like normal RAM
Date: Thu, 17 Jan 2019 07:17:24 -0800	[thread overview]
Message-ID: <1e9377c6-11a0-3bbd-763d-d9347bd556cf@intel.com> (raw)
In-Reply-To: <5ef5d5e9-9d35-fb84-b69e-7456dcf4c241@linux.intel.com>

On 1/17/19 12:19 AM, Yanmin Zhang wrote:
>>
> I didn't try pmem and I am wondering it's slower than DRAM.
> Should a flag, such like _GFP_PMEM, be added to distinguish it from
> DRAM?

Absolutely not. :)

We already have performance-differentiated memory, and lots of ways to
enumerate and select it in the kernel (all of our NUMA infrastructure).

PMEM is also just the first of many "kinds" of memory that folks want to
build in systems and use a "RAM".  We literally don't have space to put
a flag in for each type.

  reply	other threads:[~2019-01-17 15:17 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-16 18:18 [PATCH 0/4] Allow persistent memory to be used " Dave Hansen
2019-01-16 18:18 ` Dave Hansen
2019-01-16 18:19 ` [PATCH 1/4] mm/resource: return real error codes from walk failures Dave Hansen
2019-01-16 18:19   ` Dave Hansen
2019-01-16 20:38   ` Bjorn Helgaas
2019-01-16 20:38     ` Bjorn Helgaas
2019-01-16 18:19 ` [PATCH 2/4] mm/memory-hotplug: allow memory resources to be children Dave Hansen
2019-01-16 18:19   ` Dave Hansen
2019-01-16 19:16   ` Jerome Glisse
2019-01-16 23:01     ` Dave Hansen
2019-01-16 23:38       ` Jerome Glisse
2019-01-23 20:03         ` Dave Hansen
2019-01-23 20:15           ` Jerome Glisse
2019-01-18 19:58     ` Dave Hansen
2019-01-18 20:26       ` Jerome Glisse
2019-01-23 17:05   ` Michal Hocko
2019-01-16 18:19 ` [PATCH 3/4] dax/kmem: let walk_system_ram_range() search child resources Dave Hansen
2019-01-16 18:19   ` Dave Hansen
2019-01-16 18:19 ` [PATCH 4/4] dax: "Hotplug" persistent memory for use like normal RAM Dave Hansen
2019-01-16 18:19   ` Dave Hansen
2019-01-16 21:16   ` Bjorn Helgaas
2019-01-16 21:16     ` Bjorn Helgaas
2019-01-16 21:40     ` Dave Hansen
2019-01-16 21:44       ` Bjorn Helgaas
2019-01-16 21:44         ` Bjorn Helgaas
2019-01-16 22:06       ` Dan Williams
2019-01-16 22:06         ` Dan Williams
2019-01-16 21:53     ` Dave Hansen
2019-01-16 21:59       ` Bjorn Helgaas
2019-01-16 21:59         ` Bjorn Helgaas
2019-01-16 21:31   ` Dan Williams
2019-01-16 21:31     ` Dan Williams
2019-01-17  5:21   ` Du, Fan
2019-01-17 16:56     ` Dan Williams
2019-01-17 16:56       ` Dan Williams
2019-01-17  8:19   ` Yanmin Zhang
2019-01-17 15:17     ` Dave Hansen [this message]
2019-01-18  7:47       ` Yanmin Zhang
2019-01-18 15:20         ` Dave Hansen
2019-01-17 16:29 ` [PATCH 0/4] Allow persistent memory to be used " Jeff Moyer
2019-01-17 16:29   ` Jeff Moyer
2019-01-17 16:47   ` Keith Busch
2019-01-17 17:20     ` Jeff Moyer
2019-01-17 17:20       ` Jeff Moyer
2019-01-17 19:34       ` Keith Busch
2019-01-17 21:57         ` Jeff Moyer
2019-01-17 21:57           ` Jeff Moyer
2019-01-18 11:48       ` Fengguang Wu
2019-01-17 16:50   ` Dan Williams
2019-01-17 16:50     ` Dan Williams
2019-01-17 22:43   ` Dave Hansen

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