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[209.85.221.177]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-5be03ccd55esm4256294e0c.17.2026.07.06.01.27.55 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Jul 2026 01:27:55 -0700 (PDT) Received: by mail-vk1-f177.google.com with SMTP id 71dfb90a1353d-5bbd26a2729so2065389e0c.0 for ; Mon, 06 Jul 2026 01:27:55 -0700 (PDT) X-Forwarded-Encrypted: i=1; AHgh+RpBIW3qIhbpozD62UhUoUUvl2qIsrG9b1X/oRlmyFquj+3y/LALMtzsKh/RR+Ri5NoEcoUp3KpppBg/5xk=@vger.kernel.org X-Received: by 2002:a05:6102:8689:20b0:739:15ef:cdfb with SMTP id ada2fe7eead31-7427cd0c4fdmr1857356137.5.1783326475557; Mon, 06 Jul 2026 01:27:55 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260702012546.665383-1-thehajime@gmail.com> <20260705152708.582fd8d87561f600da23c0a7@linux-foundation.org> <20260705222343.5d5c78cbb54839c5efcaabf5@linux-foundation.org> In-Reply-To: <20260705222343.5d5c78cbb54839c5efcaabf5@linux-foundation.org> From: Geert Uytterhoeven Date: Mon, 6 Jul 2026 10:27:43 +0200 X-Gmail-Original-Message-ID: X-Gm-Features: AVVi8CdT4DFWW41-N3DhAV42a0PfFvRIGJDxqXDPU_cW1gDcP61ff-stnvxXAlk Message-ID: Subject: Re: [PATCH] mm: nommu: point to the write iterator upon split_vma To: Andrew Morton Cc: Matthew Wilcox , Hajime Tazaki , liam@infradead.org, ljs@kernel.org, vbabka@kernel.org, jannh@google.com, pfalcato@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Greg Ungerer Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Andrew, On Mon, 6 Jul 2026 at 07:23, Andrew Morton wrot= e: > On Mon, 6 Jul 2026 04:58:28 +0100 Matthew Wilcox wr= ote: > > On Sun, Jul 05, 2026 at 03:27:08PM -0700, Andrew Morton wrote: > > > Thanks. Unfortunately we aren't very diligent about the nommu code > > > (are we?). Perhaps appropriately - clearly this code doesn't get us= ed a > > > lot. > > > > Should we delete support for NOMMU? As you say, it doesn't get much > > testing, or presumably usage. I have this quote from #m68k a couple of > > years ago... > > Greg is busily developing kernel code. > > > : I looked at nommu very briefly when I had my 68000 board on the bench > > : but didn=E2=80=99t get anywhere. Also didn=E2=80=99t try particularly= hard. I think > > : you are better off with fuzix or OS9 if you want something unixy. > > > > (i suspect Zephyr would also be good, but it doesn't support m68k, just > > arc, arm, arm64, mips, openrisc, renesas rx, riscv, sparc, x86 and xten= sa) > > Greg, how mush use is NOMMU Linux seeing nowadays? Nommu (SH-compatible J-Core ASIC) is used in actual products, running modern kernels. The rationale is low interrupt latency without using a much more costly app CPU core + RT CPU core split. Please watch the recording of the "32bit and-or noMMU Linux BoF"[1] at LPC2025 for more info. [1] https://lpc.events/event/19/contributions/2097/ Gr{oetje,eeting}s, Geert --=20 Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k= .org In personal conversations with technical people, I call myself a hacker. Bu= t when I'm talking to journalists I just say "programmer" or something like t= hat. -- Linus Torvalds