From: Linus Torvalds <torvalds@linux-foundation.org>
To: Matthew Wilcox <willy@infradead.org>,
"Maciej W. Rozycki" <macro@orcam.me.uk>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
"the arch/x86 maintainers" <x86@kernel.org>,
"Yu Zhao" <yuzhao@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Andi Kleen" <ak@linux.intel.com>,
"Aneesh Kumar" <aneesh.kumar@linux.ibm.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Hillf Danton" <hdanton@sina.com>, "Jens Axboe" <axboe@kernel.dk>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Jonathan Corbet" <corbet@lwn.net>,
"Mel Gorman" <mgorman@suse.de>,
"Michael Larabel" <Michael@michaellarabel.com>,
"Michal Hocko" <mhocko@kernel.org>,
"Mike Rapoport" <rppt@kernel.org>, "Tejun Heo" <tj@kernel.org>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Will Deacon" <will@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
page-reclaim@google.com, "Brian Geffon" <bgeffon@google.com>,
"Jan Alexander Steffens" <heftig@archlinux.org>,
"Oleksandr Natalenko" <oleksandr@natalenko.name>,
"Steven Barrett" <steven@liquorix.net>,
"Suleiman Souhlal" <suleiman@google.com>,
"Daniel Byrne" <djbyrne@mtu.edu>,
"Donald Carr" <d@chaos-reins.com>,
"Holger Hoffstätte" <holger@applied-asynchrony.com>,
"Konstantin Kharlamov" <Hi-Angel@yandex.ru>,
"Shuang Zhai" <szhai2@cs.rochester.edu>,
"Sofia Trinh" <sofia.trinh@edi.works>,
"Vaibhav Jain" <vaibhav@linux.ibm.com>
Subject: Re: [PATCH v14 08/14] mm: multi-gen LRU: support page table walks
Date: Fri, 21 Oct 2022 09:50:01 -0700 [thread overview]
Message-ID: <CAHk-=wjrpH1+6cQQjTO6p-96ndBMiOnNH098vhS2jLybxD+7gA@mail.gmail.com> (raw)
In-Reply-To: <Y1IUMDJFScAMrCS5@casper.infradead.org>
On Thu, Oct 20, 2022 at 8:38 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Oct 20, 2022 at 07:10:46PM -0700, Linus Torvalds wrote:
> >
> > We got rid of i386 support back in 2012. Maybe it's time to get rid of
> > i486 support in 2022?
>
> Arnd suggested removing i486 last year and got a bit of pushback.
> The most convincing to my mind was Maciej:
Hmm. Maciej added to the cc.
I suspect we can just say "oh, well, use LTS kernels".
> but you can see a few other responses indicating that people have
> shipped new 486-class hardware within the last few years (!)
Hmm.. I can only find references to PC104 boards with Bay Trail
(Pentium-class Atom core, iirc), and some possible FPGA
implementations through MISTer.
There's apparently also a Vortex86DX board too, and I don't know what
core that is based off, but judging from the fact that it has a
dual-core version, it had *better* support cmpxchg8b anyway, because
without that our 64-bit atomics aren't actually atomic.
(Trying to google around, it looks like the older Vortex86SX was a
486-class CPU and did indeed lack CX8)
Intel had some embedded cores (Quark) that were based on the i486
pipeline (as can be seen from the timings), but they actually reported
themselves as Pentium-class and supported all the classic (pre-MMX)
Pentium features.
So I *really* don't think i486 class hardware is relevant any more.
Yes, I'm sure it exists (Maciej being an example), but from a kernel
development standpoint I don't think they are really relevant.
At some point, people have them as museum pieces. They might as well
run museum kernels.
Moving up to requiring cmpxchg8b doesn't sound unreasonable to me.
Linus
next prev parent reply other threads:[~2022-10-21 16:50 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-15 7:13 [PATCH v14 00/14] Multi-Gen LRU Framework Yu Zhao
2022-08-15 7:13 ` [PATCH v14 01/14] mm: x86, arm64: add arch_has_hw_pte_young() Yu Zhao
2022-08-15 7:13 ` [PATCH v14 02/14] mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG Yu Zhao
2022-08-15 7:13 ` [PATCH v14 03/14] mm/vmscan.c: refactor shrink_node() Yu Zhao
2022-08-15 7:13 ` [PATCH v14 04/14] Revert "include/linux/mm_inline.h: fold __update_lru_size() into its sole caller" Yu Zhao
2022-08-15 7:13 ` [PATCH v14 05/14] mm: multi-gen LRU: groundwork Yu Zhao
2022-08-15 7:13 ` [PATCH v14 06/14] mm: multi-gen LRU: minimal implementation Yu Zhao
2022-08-15 7:13 ` [PATCH v14 07/14] mm: multi-gen LRU: exploit locality in rmap Yu Zhao
2022-09-01 9:18 ` Nadav Amit
2022-09-02 1:17 ` Yu Zhao
2022-09-02 1:28 ` Yu Zhao
2022-08-15 7:13 ` [PATCH v14 08/14] mm: multi-gen LRU: support page table walks Yu Zhao
2022-10-13 15:04 ` Peter Zijlstra
2022-10-19 5:51 ` Yu Zhao
2022-10-19 17:40 ` Linus Torvalds
2022-10-20 14:13 ` Peter Zijlstra
2022-10-20 17:29 ` Yu Zhao
2022-10-20 17:35 ` Linus Torvalds
2022-10-20 18:55 ` Peter Zijlstra
2022-10-21 2:10 ` Linus Torvalds
2022-10-21 3:38 ` Matthew Wilcox
2022-10-21 16:50 ` Linus Torvalds [this message]
2022-10-23 14:44 ` David Gow
2022-10-23 17:55 ` Maciej W. Rozycki
2022-10-23 18:35 ` Linus Torvalds
2022-10-24 7:30 ` Arnd Bergmann
2022-10-25 16:28 ` Maciej W. Rozycki
2022-10-26 15:43 ` Arnd Bergmann
2022-10-27 23:08 ` Maciej W. Rozycki
2022-10-28 7:27 ` Arnd Bergmann
2022-10-21 10:12 ` Peter Zijlstra
2022-10-24 18:20 ` Gareth Poole
2022-10-24 19:28 ` Serentty
2022-08-15 7:13 ` [PATCH v14 09/14] mm: multi-gen LRU: optimize multiple memcgs Yu Zhao
2022-08-15 7:13 ` [PATCH v14 10/14] mm: multi-gen LRU: kill switch Yu Zhao
2022-08-15 7:13 ` [PATCH v14 11/14] mm: multi-gen LRU: thrashing prevention Yu Zhao
2022-08-15 7:13 ` [PATCH v14 12/14] mm: multi-gen LRU: debugfs interface Yu Zhao
2022-08-15 7:13 ` [PATCH v14 13/14] mm: multi-gen LRU: admin guide Yu Zhao
2022-08-15 9:06 ` Bagas Sanjaya
2022-08-15 9:12 ` Mike Rapoport
2022-08-17 22:46 ` Yu Zhao
2022-09-20 7:43 ` Bagas Sanjaya
2022-08-15 7:13 ` [PATCH v14 14/14] mm: multi-gen LRU: design doc Yu Zhao
2022-08-15 9:07 ` Bagas Sanjaya
2022-08-31 4:17 ` OpenWrt / MIPS benchmark with MGLRU Yu Zhao
2022-08-31 12:12 ` Arnd Bergmann
2022-08-31 15:13 ` Dave Hansen
2022-08-31 22:18 ` Yu Zhao
2022-09-12 0:08 ` [PATCH v14 00/14] Multi-Gen LRU Framework Andrew Morton
2022-09-15 17:56 ` Yu Zhao
2022-09-18 20:40 ` Yu Zhao
2022-09-18 23:47 ` Andrew Morton
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