From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6430A405E9 for ; Fri, 27 Oct 2023 22:34:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Lm1TUIJh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9875FC433C8; Fri, 27 Oct 2023 22:34:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698446052; bh=/vFBRcijZbBGOxe89h/NyRV9oxAUvw3cMTba9cML1uQ=; h=From:To:Cc:Subject:Date:From; b=Lm1TUIJhzUHCdygn49AWJpeCLsJhTqcNZrb+kQNXT3jQmUAypIQB/MRF0QFNWicuO DeseaDMhp5iVXtrQcpqTBdWEceWhdrMGDfbNJHIjf4lAAIO7kbS36g4GswL11pW2Zb ogNWr5fmpvEsBAy/ymHySyMDv8Q16CDeCpd0SzOQH1/t8S0tGuVitx2sECSDoBqgyI Qu7n0/SOu8OC1Td5/H96i+cVkaRbHdmBZs9NdxXwRF30hCNa+7BJAwG07qgCLawtOl z5yZJlp3DD153A1jS9aXAB/LhKalIJdZIkoBdS5ADZUUYauqLozeeLmUz72Z9tsCT/ vZzxd899T6iOg== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, jiri@resnulli.us, Jakub Kicinski Subject: [PATCH net-next] tools: ynl-gen: don't touch the output file if content is the same Date: Fri, 27 Oct 2023 15:34:08 -0700 Message-ID: <20231027223408.1865704-1-kuba@kernel.org> X-Mailer: git-send-email 2.41.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit I often regenerate all YNL files in the tree to make sure they are in sync with the codegen and specs. Generator rewrites the files unconditionally, so since make looks at file modification time to decide what to rebuild - my next build takes longer. We already generate the code to a tempfile most of the time, only overwrite the target when we have to. Before: $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:19:56.347071940 -0700 Modify: 2023-10-27 15:19:45.089000900 -0700 Change: 2023-10-27 15:19:45.089000900 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 $ ./tools/net/ynl/ynl-regen.sh -f [...] $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:19:56.347071940 -0700 Modify: 2023-10-27 15:22:18.417968446 -0700 Change: 2023-10-27 15:22:18.417968446 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 After: $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:22:41.520114221 -0700 Modify: 2023-10-27 15:22:18.417968446 -0700 Change: 2023-10-27 15:22:18.417968446 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 $ ./tools/net/ynl/ynl-regen.sh -f [...] $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:22:41.520114221 -0700 Modify: 2023-10-27 15:22:18.417968446 -0700 Change: 2023-10-27 15:22:18.417968446 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 Signed-off-by: Jakub Kicinski --- tools/net/ynl/ynl-gen-c.py | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/net/ynl/ynl-gen-c.py b/tools/net/ynl/ynl-gen-c.py index 13427436bfb7..c4003a83cd5d 100755 --- a/tools/net/ynl/ynl-gen-c.py +++ b/tools/net/ynl/ynl-gen-c.py @@ -3,6 +3,7 @@ import argparse import collections +import filecmp import os import re import shutil @@ -1168,7 +1169,7 @@ from lib import SpecFamily, SpecAttrSet, SpecAttr, SpecOperation, SpecEnumSet, S if out_file is None: self._out = os.sys.stdout else: - self._out = tempfile.TemporaryFile('w+') + self._out = tempfile.NamedTemporaryFile('w+') self._out_file = out_file def __del__(self): @@ -1177,6 +1178,10 @@ from lib import SpecFamily, SpecAttrSet, SpecAttr, SpecOperation, SpecEnumSet, S def close_out_file(self): if self._out == os.sys.stdout: return + # Avoid modifying the file if contents didn't change + self._out.flush() + if os.path.isfile(self._out_file) and filecmp.cmp(self._out.name, self._out_file, shallow=False): + return with open(self._out_file, 'w+') as out_file: self._out.seek(0) shutil.copyfileobj(self._out, out_file) -- 2.41.0