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([2001:af0:8000:1409:193:86:92:181]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49d26c300e2sm164777985e9.8.2026.09.11.04.57.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Sep 2026 04:57:35 -0700 (PDT) Message-ID: Date: Fri, 11 Sep 2026 13:57:34 +0200 Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 13/23] modpost: hash module source per-file, not per-byte To: "Lorenzo Stoakes (ARM)" Cc: Linus Torvalds , Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Masahiro Yamada , Alexey Gladkov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Arnd Bergmann , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Ilias Apalodimas , Josh Poimboeuf , Peter Zijlstra , Miguel Ojeda , Boqun Feng , Gary Guo , =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , =?UTF-8?Q?Onur_=C3=96zkan?= , Jonathan Corbet , Randy Dunlap , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, Jens Axboe References: <20260908-build-speedup-v1-0-5dc1ac01672d@kernel.org> <20260908-build-speedup-v1-13-5dc1ac01672d@kernel.org> <434a7a10-d83e-4402-be91-816bbbc15bb7@suse.com> Content-Language: en-US From: Petr Pavlu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/11/26 12:41 PM, Lorenzo Stoakes (ARM) wrote: > On Thu, Sep 10, 2026 at 02:52:50PM +0200, Petr Pavlu wrote: >> On 9/8/26 10:55 PM, Lorenzo Stoakes (ARM) wrote: >>> modpost spends a long time md4 hashing module source at a per-byte >>> granularity. >>> >>> Fix this by doing this hashing per-file instead by accumulating a per-file >>> buffer in parse_file(). >>> >>> All 11,189 .mod.c files and Module.symvers were confirmed to be identical >>> with this change applied. >>> >>> This is especially impactful for allmodconfig incremental builds (where >>> CONFIG_MODULE_SRCVERSION_ALL is set). >>> >>> Whole build, 128-thread Threadripper 9980X, best of N runs: >>> >>> before after delta >>> ------------------------------- >>> x86 allmodconfig, touch mm/vma.c, gcc 40.6s 38.2s -2.4s (-6%) >>> x86 allmodconfig, touch mm/vma.c, clang 36.2s 35.0s -1.2s (-3%) >>> >>> Assisted-by: LLM >>> Signed-off-by: Lorenzo Stoakes (ARM) >>> --- >>> scripts/mod/sumversion.c | 56 +++++++++++++++++++++++++++++++++++++----------- >>> 1 file changed, 44 insertions(+), 12 deletions(-) >> >> Support for the module srcversion is being removed in "module: remove >> MODULE_VERSION() and srcversion" [1] and scripts/mod/sumversion.c should >> be gone completely. > > Hmm, that series doesn't remove the script though, is that planned as a follow up? My reply to that series [1] notes that it should also remove scripts/mod/sumversion.c. It should be done in the next version. > > I guess I can drop this patch from the series then :) Also patch 17 I think? I agree. The module srcversion is no longer needed since build IDs are nowadays the standard mechanism for providing effectively the same functionality. While I'm not sure when the mentioned removal will land, reviewing and polishing this patch and patch 17 would IMO be wasteful at this point. [1] https://lore.kernel.org/linux-modules/4e321525-708c-4964-9937-d94ea27e8d85@suse.com/ -- Thanks, Petr