From: Dan Williams <dan.j.williams@intel.com>
To: Toshi Kani <toshi.kani@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
jgross@suse.com, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
mcgrof@suse.com, X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
stefan.bader@canonical.com, Andy Lutomirski <luto@amacapital.net>,
linux-mm@kvack.org, hmh@hmh.eng.br,
Christoph Hellwig <hch@lst.de>,
Matthew Wilcox <willy@linux.intel.com>
Subject: Re: [PATCH v9 10/10] drivers/block/pmem: Map NVDIMM with ioremap_wt()
Date: Thu, 14 May 2015 14:52:18 -0700 [thread overview]
Message-ID: <CAPcyv4je=q92aytAXLR=Eqc3yD8pdmSuyuCF+4QJRb34LFU=VQ@mail.gmail.com> (raw)
In-Reply-To: <1431551151-19124-11-git-send-email-toshi.kani@hp.com>
On Wed, May 13, 2015 at 2:05 PM, Toshi Kani <toshi.kani@hp.com> wrote:
> The pmem driver maps NVDIMM with ioremap_nocache() as we cannot
> write back the contents of the CPU caches in case of a crash.
>
> This patch changes to use ioremap_wt(), which provides uncached
> writes but cached reads, for improving read performance.
I'm thinking that for the libnd integration we don't want the pmem
driver hard coding the cache-policy decision. This is something that
should be specified to nd_pmem_region_create(). Especially
considering that platform firmware tables (NFIT) may specify the cache
policy for the range. As Matthew Wilcox mentioned offline we also
must match the DAX-to-mmap cache policy with the policy for the driver
mapping for architectures that are not capable of multiple mappings
of the same physical address with different policies.
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next prev parent reply other threads:[~2015-05-14 21:52 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-13 21:05 [PATCH v9 0/10] Support Write-Through mapping on x86 Toshi Kani
2015-05-13 21:05 ` [PATCH v9 1/10] x86, mm, pat: Set WT to PA7 slot of PAT MSR Toshi Kani
2015-05-22 6:55 ` Thomas Gleixner
2015-05-13 21:05 ` [PATCH v9 2/10] x86, mm, pat: Change reserve_memtype() for WT Toshi Kani
2015-05-22 7:01 ` Thomas Gleixner
2015-05-13 21:05 ` [PATCH v9 3/10] x86, asm: Change is_new_memtype_allowed() " Toshi Kani
2015-05-22 7:02 ` Thomas Gleixner
2015-05-13 21:05 ` [PATCH v9 4/10] x86, mm, asm-gen: Add ioremap_wt() " Toshi Kani
2015-05-22 7:08 ` Thomas Gleixner
2015-05-13 21:05 ` [PATCH v9 5/10] arch/*/asm/io.h: Add ioremap_wt() to all architectures Toshi Kani
2015-05-22 7:15 ` Thomas Gleixner
2015-05-22 14:08 ` Toshi Kani
2015-05-13 21:05 ` [PATCH v9 6/10] x86, mm, pat: Add pgprot_writethrough() for WT Toshi Kani
2015-05-22 7:16 ` Thomas Gleixner
2015-05-13 21:05 ` [PATCH v9 7/10] x86, mm, asm: Add WT support to set_page_memtype() Toshi Kani
2015-05-22 7:35 ` Thomas Gleixner
2015-05-22 15:04 ` Toshi Kani
2015-05-13 21:05 ` [PATCH v9 8/10] x86, mm: Add set_memory_wt() for WT Toshi Kani
2015-05-22 7:48 ` Thomas Gleixner
2015-05-22 15:30 ` Toshi Kani
2015-05-13 21:05 ` [PATCH v9 9/10] x86, mm, pat: Refactor !pat_enabled handling Toshi Kani
2015-05-22 8:34 ` Thomas Gleixner
2015-05-22 16:27 ` Toshi Kani
2015-05-13 21:05 ` [PATCH v9 10/10] drivers/block/pmem: Map NVDIMM with ioremap_wt() Toshi Kani
2015-05-14 21:52 ` Dan Williams [this message]
2015-05-14 22:20 ` Toshi Kani
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