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| author | Jakub Kicinski <kuba@kernel.org> | 2023-10-27 15:34:08 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-11-01 22:14:00 -0700 |
| commit | 2b7ac0c87d985c92e519995853c52b9649ea4b07 (patch) | |
| tree | e15c0ce79a0e68cd9d9949663fefb302245f5d60 | |
| parent | 05f0431bb90f2ee3657e7fc2678f11a1f9b778b7 (diff) | |
| download | linux-2b7ac0c87d985c92e519995853c52b9649ea4b07.tar.gz linux-2b7ac0c87d985c92e519995853c52b9649ea4b07.tar.bz2 linux-2b7ac0c87d985c92e519995853c52b9649ea4b07.zip | |
tools: ynl-gen: don't touch the output file if content is the same
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
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231027223408.1865704-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rwxr-xr-x | tools/net/ynl/ynl-gen-c.py | 7 |
1 files changed, 6 insertions, 1 deletions
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 @@ class CodeWriter: 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 @@ class CodeWriter: 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) |