linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: afzal mohammed <afzal.mohd.ma@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	"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

  reply	other threads:[~2020-06-07 16:11 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-31  9:32 [PATCH 0/3] Highmem support for 32-bit RISC-V Eric Lin
2020-03-31  9:32 ` [PATCH 1/3] riscv/mm: Add pkmap region and CONFIG_HIGHMEM Eric Lin
2020-03-31  9:32 ` [PATCH 2/3] riscv/mm: Implement kmap() and kmap_atomic() Eric Lin
2020-03-31  9:32 ` [PATCH 3/3] riscv/mm: Add pkmap in print_vm_layout() Eric Lin
2020-04-02  9:31 ` [PATCH 0/3] Highmem support for 32-bit RISC-V Arnd Bergmann
2020-04-08  3:51   ` Alan Kao
2020-04-08 14:40     ` Arnd Bergmann
2020-04-14 15:17       ` afzal mohammed
2020-04-14 19:29         ` Arnd Bergmann
2020-04-15 13:54           ` afzal mohammed
2020-05-03 14:50             ` afzal mohammed
2020-05-03 20:20               ` Arnd Bergmann
2020-05-04  9:10                 ` 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
2020-06-07 12:59                                         ` ARM: vmsplit 4g/4g afzal mohammed
2020-06-07 16:11                                           ` Russell King - ARM Linux admin [this message]
2020-06-08 11:09                                             ` 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200607161116.GN1551@shell.armlinux.org.uk \
    --to=linux@armlinux.org.uk \
    --cc=afzal.mohd.ma@gmail.com \
    --cc=arnd@arndb.de \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).