All of lore.kernel.org
 help / color / mirror / Atom feed
From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Yury Norov <yury.norov@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Andreas Schwab <schwab@suse.de>,
	linux-kernel@vger.kernel.org,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Dmitry Vyukov <dvyukov@google.com>,
	Valentin Schneider <vschneid@redhat.com>,
	Sander Vanheule <sander@svanheule.net>,
	Alexey Klimov <klimov.linux@gmail.com>,
	Eric Biggers <ebiggers@google.com>,
	linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: [PATCH v2 5/5] lib/cpumask: add FORCE_NR_CPUS config option
Date: Tue, 18 Oct 2022 17:15:41 +0200	[thread overview]
Message-ID: <CAMuHMdVjViT8-VMPuKZz2O1sudy5ogHpzVYM_P+isjRRUNgirw@mail.gmail.com> (raw)
In-Reply-To: <Y06/SipcWdh4uIqd@yury-laptop>

Hi Yuri,

On Tue, Oct 18, 2022 at 5:01 PM Yury Norov <yury.norov@gmail.com> wrote:
> On Tue, Oct 18, 2022 at 05:44:09PM +0300, Andy Shevchenko wrote:
> > On Tue, Oct 18, 2022 at 07:35:09AM -0700, Yury Norov wrote:
> > > On Tue, Oct 18, 2022 at 03:50:31PM +0200, Geert Uytterhoeven wrote:
> >
> > ...
> >
> > > For those who choose FORCE_NR_CPUS, it's required to set NR_CPUS
> > > to a value that matches to what's parsed from DT.
> > >
> > > Can you please look at the draft below that disables FORCE_NR_CPUS
> > > in allmodconfig? If it's OK with you, I'll send a patch. If you think
> > > that there are architectures where it's not possible to set correct
> > > NR_CPUS at compile time for some reason, I'll add ARCH_UNFORCE_NR_CPUS
> > > option.
> >
> > Instead you may simply add
> >
> >       depends on CONFIG_$ARCH/$MACHINE=n
> >
> > and so on to the FORCE_NR_CPUS, no?
>
> Yes, if there's just one machine like that. If there's many of them, the
> 'depends' list would be too long.
>
> I hope there's no such a weird machines, and we don't need that at
> all. Let's see what Geert will say.

I haven't tried the patch from your other email yet, but I did try
CONFIG_NR_CPUS=4 and CONFIG_FORCE_NR_CPUS=y on
Icicle earlier today.

There was no warning, as the number of CPUs did match, but the
fourth CPU (cpu@4, i.e. the fifth core in DT) failed to come online:

    CPU3: failed to come online
    smp: Brought up 1 node, 3 CPUs

BTW, it behaves the same with CONFIG_FORCE_NR_CPUS=n.
Increasing CONFIG_NR_CPUS (before I used 8) makes the fourth
CPU core come online again.

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

WARNING: multiple messages have this Message-ID (diff)
From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Yury Norov <yury.norov@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Andreas Schwab <schwab@suse.de>,
	 linux-kernel@vger.kernel.org,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	 Andrew Morton <akpm@linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	 Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	 "Paul E . McKenney" <paulmck@kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Dmitry Vyukov <dvyukov@google.com>,
	 Valentin Schneider <vschneid@redhat.com>,
	Sander Vanheule <sander@svanheule.net>,
	 Alexey Klimov <klimov.linux@gmail.com>,
	Eric Biggers <ebiggers@google.com>,
	 linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: [PATCH v2 5/5] lib/cpumask: add FORCE_NR_CPUS config option
Date: Tue, 18 Oct 2022 17:15:41 +0200	[thread overview]
Message-ID: <CAMuHMdVjViT8-VMPuKZz2O1sudy5ogHpzVYM_P+isjRRUNgirw@mail.gmail.com> (raw)
In-Reply-To: <Y06/SipcWdh4uIqd@yury-laptop>

Hi Yuri,

On Tue, Oct 18, 2022 at 5:01 PM Yury Norov <yury.norov@gmail.com> wrote:
> On Tue, Oct 18, 2022 at 05:44:09PM +0300, Andy Shevchenko wrote:
> > On Tue, Oct 18, 2022 at 07:35:09AM -0700, Yury Norov wrote:
> > > On Tue, Oct 18, 2022 at 03:50:31PM +0200, Geert Uytterhoeven wrote:
> >
> > ...
> >
> > > For those who choose FORCE_NR_CPUS, it's required to set NR_CPUS
> > > to a value that matches to what's parsed from DT.
> > >
> > > Can you please look at the draft below that disables FORCE_NR_CPUS
> > > in allmodconfig? If it's OK with you, I'll send a patch. If you think
> > > that there are architectures where it's not possible to set correct
> > > NR_CPUS at compile time for some reason, I'll add ARCH_UNFORCE_NR_CPUS
> > > option.
> >
> > Instead you may simply add
> >
> >       depends on CONFIG_$ARCH/$MACHINE=n
> >
> > and so on to the FORCE_NR_CPUS, no?
>
> Yes, if there's just one machine like that. If there's many of them, the
> 'depends' list would be too long.
>
> I hope there's no such a weird machines, and we don't need that at
> all. Let's see what Geert will say.

I haven't tried the patch from your other email yet, but I did try
CONFIG_NR_CPUS=4 and CONFIG_FORCE_NR_CPUS=y on
Icicle earlier today.

There was no warning, as the number of CPUs did match, but the
fourth CPU (cpu@4, i.e. the fifth core in DT) failed to come online:

    CPU3: failed to come online
    smp: Brought up 1 node, 3 CPUs

BTW, it behaves the same with CONFIG_FORCE_NR_CPUS=n.
Increasing CONFIG_NR_CPUS (before I used 8) makes the fourth
CPU core come online again.

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

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2022-10-18 15:16 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-05 23:08 [PATCH v2 0/5] cpumask: cleanup nr_cpu_ids vs nr_cpumask_bits mess Yury Norov
2022-09-05 23:08 ` [PATCH v2 1/5] smp: don't declare nr_cpu_ids if NR_CPUS == 1 Yury Norov
2022-09-06  8:53   ` Peter Zijlstra
2022-09-06 14:06     ` Yury Norov
2022-09-06 14:36       ` Peter Zijlstra
2022-09-06 15:01         ` Andy Shevchenko
2022-09-06 17:53           ` Peter Zijlstra
2022-09-06 15:07         ` Yury Norov
2022-09-07  8:02         ` David Laight
2022-09-05 23:08 ` [PATCH v2 2/5] smp: add set_nr_cpu_ids() Yury Norov
2022-09-05 23:08 ` [PATCH v2 3/5] lib/cpumask: delete misleading comment Yury Norov
2022-09-05 23:08 ` [PATCH v2 4/5] lib/cpumask: deprecate nr_cpumask_bits Yury Norov
2022-09-05 23:08 ` [PATCH v2 5/5] lib/cpumask: add FORCE_NR_CPUS config option Yury Norov
2022-10-18  8:21   ` Geert Uytterhoeven
2022-10-18 13:15     ` Geert Uytterhoeven
2022-10-18 13:15       ` Geert Uytterhoeven
2022-10-18 13:41       ` Andreas Schwab
2022-10-18 13:41         ` Andreas Schwab
2022-10-18 13:50         ` Geert Uytterhoeven
2022-10-18 13:50           ` Geert Uytterhoeven
2022-10-18 14:35           ` Yury Norov
2022-10-18 14:35             ` Yury Norov
2022-10-18 14:44             ` Andy Shevchenko
2022-10-18 14:44               ` Andy Shevchenko
2022-10-18 14:59               ` Yury Norov
2022-10-18 14:59                 ` Yury Norov
2022-10-18 15:15                 ` Geert Uytterhoeven [this message]
2022-10-18 15:15                   ` Geert Uytterhoeven
2022-10-18 16:16                   ` Yury Norov
2022-10-18 16:16                     ` Yury Norov
2022-10-19  6:58                     ` Geert Uytterhoeven
2022-10-19  6:58                       ` Geert Uytterhoeven
2022-09-06  8:55 ` [PATCH v2 0/5] cpumask: cleanup nr_cpu_ids vs nr_cpumask_bits mess Peter Zijlstra
2022-09-06 12:06   ` Valentin Schneider
2022-09-06 14:38     ` Peter Zijlstra
2022-09-06 15:45       ` Valentin Schneider
2022-09-06 16:26         ` Yury Norov
2022-09-06 14:48     ` Yury Norov
2022-09-06 14:35   ` Yury Norov
2022-09-15 14:45 ` Yury Norov

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=CAMuHMdVjViT8-VMPuKZz2O1sudy5ogHpzVYM_P+isjRRUNgirw@mail.gmail.com \
    --to=geert@linux-m68k.org \
    --cc=akpm@linux-foundation.org \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=dvyukov@google.com \
    --cc=ebiggers@google.com \
    --cc=klimov.linux@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=linux@rasmusvillemoes.dk \
    --cc=paulmck@kernel.org \
    --cc=peterz@infradead.org \
    --cc=sander@svanheule.net \
    --cc=schwab@suse.de \
    --cc=sfr@canb.auug.org.au \
    --cc=tglx@linutronix.de \
    --cc=vbabka@suse.cz \
    --cc=vschneid@redhat.com \
    --cc=yury.norov@gmail.com \
    /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.