From: Will Deacon <will.deacon@arm.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org,
bhelgaas@google.com, mark.brown@linaro.org
Subject: Re: [PATCH] PCI: generic: map config window in one go
Date: Fri, 29 Jan 2016 14:28:31 +0000 [thread overview]
Message-ID: <20160129142831.GF4541@arm.com> (raw)
In-Reply-To: <1454077035-23872-1-git-send-email-ard.biesheuvel@linaro.org>
Hi Ard,
On Fri, Jan 29, 2016 at 03:17:15PM +0100, Ard Biesheuvel wrote:
> Instead of iterating over the PCI config window and performing individual
> ioremap() calls on all the adjacent slices, perform a single ioremap() to
> map the entire region, and divvy it up later. This not only prevents
> leaving some of it mapped if we fail half way through, it also ensures that
> archs that support huge-vmap can use section mappings to perform the
> mapping.
>
> On my Seattle A0 box, this transforms 128 separate 1 MB mappings that are
> mapped down to 4 KB pages into a single 128 MB mapping using 2 MB sections,
> saving 512 KB worth of page tables.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
The code was written this way in response to feedback during driver review
that we couldn't necessarily grab that much contiguous vmalloc space on
32-bit ARM. Unless that's changed, we probably want to to predicate this
change on having a 64-bit arch.
Will
WARNING: multiple messages have this Message-ID (diff)
From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] PCI: generic: map config window in one go
Date: Fri, 29 Jan 2016 14:28:31 +0000 [thread overview]
Message-ID: <20160129142831.GF4541@arm.com> (raw)
In-Reply-To: <1454077035-23872-1-git-send-email-ard.biesheuvel@linaro.org>
Hi Ard,
On Fri, Jan 29, 2016 at 03:17:15PM +0100, Ard Biesheuvel wrote:
> Instead of iterating over the PCI config window and performing individual
> ioremap() calls on all the adjacent slices, perform a single ioremap() to
> map the entire region, and divvy it up later. This not only prevents
> leaving some of it mapped if we fail half way through, it also ensures that
> archs that support huge-vmap can use section mappings to perform the
> mapping.
>
> On my Seattle A0 box, this transforms 128 separate 1 MB mappings that are
> mapped down to 4 KB pages into a single 128 MB mapping using 2 MB sections,
> saving 512 KB worth of page tables.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
The code was written this way in response to feedback during driver review
that we couldn't necessarily grab that much contiguous vmalloc space on
32-bit ARM. Unless that's changed, we probably want to to predicate this
change on having a 64-bit arch.
Will
next prev parent reply other threads:[~2016-01-29 14:28 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 14:17 [PATCH] PCI: generic: map config window in one go Ard Biesheuvel
2016-01-29 14:17 ` Ard Biesheuvel
2016-01-29 14:19 ` Ard Biesheuvel
2016-01-29 14:19 ` Ard Biesheuvel
2016-01-29 14:22 ` Ard Biesheuvel
2016-01-29 14:22 ` Ard Biesheuvel
2016-01-29 14:28 ` Will Deacon [this message]
2016-01-29 14:28 ` Will Deacon
2016-01-29 14:32 ` Ard Biesheuvel
2016-01-29 14:32 ` Ard Biesheuvel
2016-01-29 14:52 ` Arnd Bergmann
2016-01-29 14:52 ` Arnd Bergmann
2016-02-05 10:48 ` Ard Biesheuvel
2016-02-05 10:48 ` Ard Biesheuvel
2016-02-05 13:37 ` Arnd Bergmann
2016-02-05 13:37 ` Arnd Bergmann
2016-02-05 14:09 ` Ard Biesheuvel
2016-02-05 14:09 ` Ard Biesheuvel
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