Linux 6.2 and up (commit [f1f1f2569901ec5b9d425f2e91c09a0e320768f3][1])
provides a fast path for the number of open files for the process.
From the [Linux docs][2]:
> The number of open files for the process is stored in 'size' member of
> `stat()` output for /proc/<pid>/fd for fast access.
[1]: f1f1f25699
[2]: https://docs.kernel.org/filesystems/proc.html#proc-pid-fd-list-of-symlinks-to-open-files
This patch adds a fast-path for Kernels that support this, and falls back
to the slow path if the Size fields is zero.
Comparing on a Fedora 38 (kernel 6.2.9-300.fc38.x86_64):
Before/After:
go test -bench ^BenchmarkGetTotalUsedFds$ -run ^$ ./pkg/fileutils/
BenchmarkGetTotalUsedFds 57264 18595 ns/op 408 B/op 10 allocs/op
BenchmarkGetTotalUsedFds 370392 3271 ns/op 40 B/op 3 allocs/op
Note that the slow path has 1 more file-descriptor, due to the open
file-handle for /proc/<pid>/fd during the calculation.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit ec79d0fc05)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Use File.Readdirnames instead of os.ReadDir, as we're only interested in
the number of files, and results don't have to be sorted.
Before:
BenchmarkGetTotalUsedFds-5 149272 7896 ns/op 945 B/op 20 allocs/op
After:
BenchmarkGetTotalUsedFds-5 153517 7644 ns/op 408 B/op 10 allocs/op
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit eaa9494b71)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Commit 8d56108ffb moved this function from
the generic (no build-tags) fileutils.go to a unix file, adding "freebsd"
to the build-tags.
This likely was a wrong assumption (as other files had freebsd build-tags).
FreeBSD's procfs does not mention `/proc/<pid>/fd` in the manpage, and
we don't test FreeBSD in CI, so let's drop it, and make this a Linux-only
file.
While updating also dropping the import-tag, as we're planning to move
this file internal to the daemon.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 252e94f499)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2023-06-30 18:29:17 +02:00
Renamed from pkg/fileutils/fileutils_unix.go (Browse further)
