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Message-ID: <20150529091129.GC31435@pd.tnic>
Date: Fri, 29 May 2015 11:11:30 +0200
From: Borislav Petkov <bp@...en8.de>
To: Toshi Kani <toshi.kani@...com>,
Dan Williams <dan.j.williams@...el.com>,
Ross Zwisler <ross.zwisler@...ux.intel.com>
Cc: hpa@...or.com, tglx@...utronix.de, mingo@...hat.com,
akpm@...ux-foundation.org, arnd@...db.de, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, x86@...nel.org,
linux-nvdimm@...ts.01.org, jgross@...e.com,
stefan.bader@...onical.com, luto@...capital.net, hmh@....eng.br,
yigal@...xistor.com, konrad.wilk@...cle.com, Elliott@...com,
mcgrof@...e.com, hch@....de
Subject: Re: [PATCH v10 12/12] drivers/block/pmem: Map NVDIMM with
ioremap_wt()
On Wed, May 27, 2015 at 09:19:04AM -0600, Toshi Kani 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.
>
> Signed-off-by: Toshi Kani <toshi.kani@...com>
> ---
> drivers/block/pmem.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c
> index eabf4a8..095dfaa 100644
> --- a/drivers/block/pmem.c
> +++ b/drivers/block/pmem.c
> @@ -139,11 +139,11 @@ static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
> }
>
> /*
> - * Map the memory as non-cachable, as we can't write back the contents
> + * Map the memory as write-through, as we can't write back the contents
> * of the CPU caches in case of a crash.
> */
> err = -ENOMEM;
> - pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size);
> + pmem->virt_addr = ioremap_wt(pmem->phys_addr, pmem->size);
> if (!pmem->virt_addr)
> goto out_release_region;
Dan, Ross, what about this one?
ACK to pick it up as a temporary solution?
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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