From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: afzal mohammed <afzal.mohd.ma@gmail.com>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
Arnd Bergmann <arnd@arndb.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: ARM: vmsplit 4g/4g
Date: Sun, 7 Jun 2020 17:11:16 +0100 [thread overview]
Message-ID: <20200607161116.GN1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20200607125932.GA4576@afzalpc>
On Sun, Jun 07, 2020 at 06:29:32PM +0530, afzal mohammed wrote:
> Hi,
>
> On Sat, May 16, 2020 at 09:35:57AM +0200, Arnd Bergmann wrote:
> > On Sat, May 16, 2020 at 8:06 AM afzal mohammed <afzal.mohd.ma@gmail.com> wrote:
>
> > > Okay, so the conclusion i take is,
> > > 1. VMSPLIT 4G/4G have to live alongside highmem
> > > 2. For user space copy, do pinning followed by kmap
>
> > Right, though kmap_atomic() should be sufficient here
> > because it is always a short-lived mapping.
>
> get_user_pages_fast() followed by kmap_atomic() & then memcpy() seems
> to work in principle for user copy.
Have you done any performance evaluation of the changes yet? I think
it would be a good idea to keep that in the picture. If there's any
significant regression, then that will need addressing.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up
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next prev parent reply other threads:[~2020-06-07 16:13 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200331093241.3728-1-tesheng@andestech.com>
[not found] ` <CAK8P3a3LokurC0n9XiwtPQh9ZgQcswMKY4b+TEsQh1VgYDNeWA@mail.gmail.com>
[not found] ` <20200408035118.GA1451@andestech.com>
[not found] ` <CAK8P3a1JS3_2fWrhNTZx0eTWjJa-GTb4AscTPqydpSP5EB15Yw@mail.gmail.com>
[not found] ` <20200414151748.GA5624@afzalpc>
[not found] ` <CAK8P3a0JW9x-Wk9Ec3+zLjPHbWAvPQx8MF-xe-PnWUgEjRAuTg@mail.gmail.com>
[not found] ` <20200415135407.GA6553@afzalpc>
[not found] ` <20200503145017.GA5074@afzalpc>
[not found] ` <CAK8P3a3OC5UO72rTDWi6+XgmExJmkATEjscq8hns8Bng06OpcQ@mail.gmail.com>
2020-05-04 9:10 ` [PATCH 0/3] Highmem support for 32-bit RISC-V afzal mohammed
2020-05-04 11:27 ` Arnd Bergmann
2020-05-11 14:21 ` ARM: static kernel in vmalloc space (was Re: [PATCH 0/3] Highmem support for 32-bit RISC-V) afzal mohammed
2020-05-11 15:29 ` Arnd Bergmann
2020-05-12 10:47 ` ARM: static kernel in vmalloc space afzal mohammed
2020-05-12 19:49 ` Arnd Bergmann
2020-05-14 11:17 ` afzal mohammed
2020-05-14 12:41 ` Arnd Bergmann
2020-05-14 13:35 ` afzal mohammed
2020-05-14 14:44 ` afzal mohammed
2020-05-14 15:32 ` Arnd Bergmann
2020-05-16 6:06 ` afzal mohammed
2020-05-16 7:35 ` Arnd Bergmann
[not found] ` <20200607125932.GA4576@afzalpc>
2020-06-07 16:11 ` Russell King - ARM Linux admin [this message]
2020-06-08 11:09 ` ARM: vmsplit 4g/4g afzal mohammed
2020-06-10 10:10 ` Linus Walleij
2020-06-12 10:25 ` afzal mohammed
2020-06-15 9:11 ` Linus Walleij
2020-06-15 10:01 ` afzal mohammed
2020-06-07 19:26 ` Arnd Bergmann
2020-06-08 11:18 ` afzal mohammed
2020-06-08 14:43 ` Arnd Bergmann
2020-06-08 15:17 ` afzal mohammed
2020-06-09 12:15 ` afzal mohammed
2020-06-09 14:22 ` Arnd Bergmann
2020-05-14 16:25 ` ARM: static kernel in vmalloc space Russell King - ARM Linux admin
2020-05-14 21:12 ` Arnd Bergmann
2020-05-14 23:40 ` Russell King - ARM Linux admin
2020-05-15 15:41 ` Arnd Bergmann
2020-07-30 9:33 ` Linus Walleij
2020-07-30 10:17 ` Arnd Bergmann
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