Received-SPF: pass (google.com: domain of linux-kernel+bounces-177406-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Message-ID: <59b2fc5781c65fcedbac21142408ed6e7824e84b.camel@physik.fu-berlin.de>
Subject: Re: [GIT PULL] alpha: cleanups and build fixes for 6.10
From: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
To: Akira Yokosawa <akiyks@gmail.com>, paulmck@kernel.org
Cc: arnd@arndb.de, ink@jurassic.park.msu.ru, linux-alpha@vger.kernel.org, 
 linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
 mattst88@gmail.com,  richard.henderson@linaro.org,
 torvalds@linux-foundation.org,  viro@zeniv.linux.org.uk, Ulrich Teichert
 <krypton@ulrich-teichert.org>
Date: Mon, 13 May 2024 11:26:14 +0200
In-Reply-To: <99765904-3f35-4c78-998e-b444a6ab90e4@gmail.com>
References: <a8241a71-2b7d-4be0-8772-5c3b40fb5302@paulmck-laptop>
	 <99765904-3f35-4c78-998e-b444a6ab90e4@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.52.1 
Precedence: bulk
MIME-Version: 1.0

On Mon, 2024-05-13 at 12:50 +0900, Akira Yokosawa wrote:
> > So why didn't the people running current mainline on pre-EV56 Alpha
> > systems notice?  One possibility is that they are upgrading their
> > kernels only occasionally.  Another possibility is that they are seeing
> > the failures, but are not tracing the obtuse failure modes back to the
> > change(s) in question.  Yet another possibility is that the resulting
> > failures are very low probability, with mean times to failure that are
> > so long that you won't notice anything on a single system.
>=20
> Another possibility is that the Jensen system was booted into uni process=
er
> mode.  Looking at the early boot log [1] provided by Ulrich (+CCed) back =
in
> Sept. 2021, I see the following by running "grep -i cpu":
>=20
> > > > [1] https://marc.info/?l=3Dlinux-alpha&m=3D163265555616841&w=3D2
>=20
> [    0.000000] Memory: 90256K/131072K available (8897K kernel code, 9499K=
 rwdata, \
> 2704K rodata, 312K init, 437K bss, 40816K reserved, 0K cma-reserved) [   =
 0.000000] \
> random: get_random_u64 called from __kmem_cache_create+0x54/0x600 with cr=
ng_init=3D0 [  \
> 0.000000] SLUB: HWalign=3D64, Order=3D0-3, MinObjects=3D0, CPUs=3D1, Node=
s=3D1 [    0.000000]
>                                                      ^^^^^^
>=20
> Without any concurrent atomic updates, the "broken" atomic accesses won't
> matter, I guess.

At least from my perspective, the machines that matter for hobbyists are un=
i-processors,
i.e. workstations. I don't know of any early Alpha workstations from the ti=
p of my head
that are multi-processor.

Adrian

--=20
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913