From: Dan Williams <dan.j.williams@intel.com>
To: Matthew Wilcox <mawilcox@microsoft.com>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Toshi Kani <toshi.kani@hpe.com>,
Nilesh Choudhury <nilesh.choudhury@oracle.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Kai Zhang <kai.ka.zhang@oracle.com>
Subject: Re: [PATCH 4/5] mm: fix cache mode of dax pmd mappings
Date: Tue, 6 Sep 2016 10:32:16 -0700 [thread overview]
Message-ID: <CAPcyv4gZK33SH7FjZDYpkf-9peeZ0E3pZu=ZjmHwSBxdh4zj-g@mail.gmail.com> (raw)
In-Reply-To: <DM2PR21MB00892878E2A17E076A18C795CBF90@DM2PR21MB0089.namprd21.prod.outlook.com>
On Tue, Sep 6, 2016 at 10:20 AM, Matthew Wilcox <mawilcox@microsoft.com> wrote:
> I have no objection to this patch going in for now.
>
> Longer term, surely we want to track what mode the PFNs are mapped in? There are various bizarre suppositions out there about how persistent memory should be mapped, and it's probably better if the kernel ignores what the user specifies and keeps everything sane. I've read the dire warnings in the Intel architecture manual and I have no desire to deal with the inevitable bug reports on some hardware I don't own and requires twenty weeks of operation in order to observe the bug.
Is there a way for userspace to establish mappings with different
cache modes, besides via /dev/mem? That was the motivation for
CONFIG_IO_STRICT_DEVMEM.
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next prev parent reply other threads:[~2016-09-06 17:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-06 16:49 [PATCH 0/5] device-dax and huge-page dax fixes for 4.8-rc6 Dan Williams
2016-09-06 16:49 ` [PATCH 1/5] dax: fix mapping size check Dan Williams
2016-09-06 16:49 ` [PATCH 2/5] dax: fix offset to physical address translation Dan Williams
2016-09-10 1:00 ` Dan Williams
2016-09-06 16:49 ` [PATCH 3/5] mm: fix show_smap() for zone_device-pmd ranges Dan Williams
2016-09-06 20:16 ` Andrew Morton
2016-09-06 16:49 ` [PATCH 4/5] mm: fix cache mode of dax pmd mappings Dan Williams
2016-09-06 17:20 ` Matthew Wilcox
2016-09-06 17:32 ` Dan Williams [this message]
2016-09-06 20:17 ` Andrew Morton
2016-09-06 21:52 ` Dan Williams
2016-09-07 19:39 ` Kani, Toshimitsu
2016-09-07 19:45 ` Dan Williams
2016-09-06 16:49 ` [PATCH 5/5] mm: cleanup pfn_t usage in track_pfn_insert() Dan Williams
2016-09-06 20:20 ` Andrew Morton
2016-09-06 20:30 ` Dan Williams
2016-09-07 5:12 ` Anshuman Khandual
2016-09-07 15:47 ` Dan Williams
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