From: Geert Uytterhoeven <geert@linux-m68k.org>
To: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Greg Ungerer <gerg@linux-m68k.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Matthew Wilcox <willy@infradead.org>,
linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH/RFC] m68k: Add full preempt support
Date: Mon, 9 Oct 2023 14:00:48 +0200 [thread overview]
Message-ID: <CAMuHMdUbHS3tvLF3_JaG=0Hoxcwf71HGbSX+mo2WXQruWSL=nQ@mail.gmail.com> (raw)
In-Reply-To: <61d3b62380fb78b87003a09cc08827fb28de7942.camel@physik.fu-berlin.de>
Hi Adrian,
On Mon, Oct 9, 2023 at 1:45 PM John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
> On Mon, 2023-10-09 at 13:29 +0200, Geert Uytterhoeven wrote:
> > On Fri, Oct 6, 2023 at 4:49 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > Currently, a Preemptible Kernel is only supported on the Coldfire CPU
> > > family. Extend preempt support to the full Classic M68K CPU family
> > > (68020+ with MMU, and 68000-derivatives without MMU).
> > >
> > > Make sure preemption is disabled in loops involving cache and TLB
> > > flushing.
> > >
> > > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > > ---
> > > Tested on ARAnyM, using none/voluntary/full preemption.
> >
> > bloat-o-meter summaries for atari_defconfig:
> >
> > PREEMPT_NONE -> PREEMPT_VOLUNTARY:
> >
> > add/remove: 0/0 grow/shrink: 238/30 up/down: 2804/-748 (2056)
> > Total: Before=4478149, After=4480205, chg +0.05%
> >
> > PREEMPT_VOLUNTARY -> PREEMPT:
> >
> > add/remove: 735/277 grow/shrink: 3050/347 up/down: 244359/-11440 (232919)
> > Total: Before=4480205, After=4713124, chg +5.20%
> >
> > Ouch.
>
> What exactly does the change document? More scheduling events?
No, kernel image size. Hence enabling full preemption increases kernel
size by ca. 229 KiB (which is more or less the equivalent size increase of
upgrading the kernel by 10 releases).
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2023-10-09 12:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-06 14:49 [PATCH/RFC] m68k: Add full preempt support Geert Uytterhoeven
2023-10-09 11:29 ` Geert Uytterhoeven
2023-10-09 11:45 ` John Paul Adrian Glaubitz
2023-10-09 12:00 ` Geert Uytterhoeven [this message]
2023-10-09 12:36 ` Greg Ungerer
2023-10-16 12:23 ` Geert Uytterhoeven
2023-10-16 20:33 ` Michael Schmitz
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='CAMuHMdUbHS3tvLF3_JaG=0Hoxcwf71HGbSX+mo2WXQruWSL=nQ@mail.gmail.com' \
--to=geert@linux-m68k.org \
--cc=gerg@linux-m68k.org \
--cc=glaubitz@physik.fu-berlin.de \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-m68k@lists.linux-m68k.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=vincent.guittot@linaro.org \
--cc=willy@infradead.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.