From: "Arnd Bergmann" <arnd@arndb.de>
To: "Linus Torvalds" <torvalds@linux-foundation.org>,
"Maciej W. Rozycki" <macro@orcam.me.uk>
Cc: "Matthew Wilcox" <willy@infradead.org>,
"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: Mon, 24 Oct 2022 09:30:09 +0200 [thread overview]
Message-ID: <ddb4a078-4d81-4124-8da0-6d7fbd3cd5c7@app.fastmail.com> (raw)
In-Reply-To: <CAHk-=wgNZNNd4t004x0ehXm=DA+JmYY=0MgVNDXUtoV4ApyXvQ@mail.gmail.com>
On Sun, Oct 23, 2022, at 20:35, Linus Torvalds wrote:
>
> Honestly, I wouldn't mind upgrading the minimum requirements to at
> least M586TSC - leaving some of those early "fake Pentium" clones
> behind too. Because 'rdtsc' is probably an even worse issue than
> CMPXCHG8B.
Kconfig treats X86_CMPXCHG64 as a strict subset of X86_TSC (except
when enabling X86_PAE, which relies on cx8), so requiring both
sounds like a good idea.
From the Kconfig history, I see you initially only enabled
cx8 unconditionally for a couple of CPUs in 982d007a6eec ("x86:
Optimize cmpxchg64() at build-time some more"), and Matthew
Whitehead extended that list in f960cfd12650 ("x86/Kconfig:
Add missing i586-class CPUs to the X86_CMPXCHG64 Kconfig group").
There are still a handful of CPUs that according to [1]
claim cx8 support that we leave disabled, specifically the
Kconfig symbols for MWINCHIP3D, MCRUSOE, MEFFICEON, MCYRIXIII,
MVIAC3_2 and MVIAC7 should have both tsc and cx8, while the
older MWINCHIPC6 and a small subset of M586 (Cyrix 6x86mx, C-II
and AMD K5) apparently have cx8 but not tsc.
Would you drop support for the 686-class chips that currently
don't use cmpxchg8b, or just remove CONFIG_X86_CMPXCHG64 and
assume they work after all?
Arnd
[1] https://reactos.org/wiki/Supported_Hardware/CPU
next prev parent reply other threads:[~2022-10-24 7:33 UTC|newest]
Thread overview: 64+ 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
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 [this message]
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 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 20:47 ` [PATCH v14-fix 01/11] mm: multi-gen LRU: update admin guide Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 02/11] mm: multi-gen LRU: add comment in lru_gen_use_mm() Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 03/11] mm: multi-gen LRU: warn on !ptep_test_and_clear_young() Yu Zhao
2022-09-18 23:47 ` Andrew Morton
2022-09-18 23:53 ` Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 04/11] mm: multi-gen LRU: fix warning from __rcu Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 05/11] mm: multi-gen LRU: fix warning from seq_is_valid() Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 06/11] mm: multi-gen LRU: delete overcautious VM_WARN_ON_ONCE() Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 07/11] mm: multi-gen LRU: dial down MAX_LRU_BATCH Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 08/11] mm: multi-gen LRU: delete newline in kswapd_age_node() Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 09/11] mm: multi-gen LRU: add comment in lru_gen_look_around() Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 10/11] mm: multi-gen LRU: fixed long-tailed direct reclaim latency Yu Zhao
2022-09-18 20:47 ` [PATCH v14-fix 11/11] mm: multi-gen LRU: refactor get_nr_evictable() Yu Zhao
2022-09-18 23:47 ` [PATCH v14 00/14] Multi-Gen LRU Framework Andrew Morton
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