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author | Yuval Pavel Zholkover <paulzhol@gmail.com> | 2019-01-07 02:06:38 +0200 |
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committer | Ian Lance Taylor <iant@golang.org> | 2019-01-09 05:04:26 +0000 |
commit | 79c50c4d5728d785485fce8c75b9c2b2f93641ea (patch) | |
tree | 91d34fcaffae6660c2176a4ca9a5cebe1d62938c | |
parent | 9473c044f1d492a6ba49ec695042dec4365d70ca (diff) | |
download | go-79c50c4d5728d785485fce8c75b9c2b2f93641ea.tar.gz go-79c50c4d5728d785485fce8c75b9c2b2f93641ea.zip |
os: disable the use of netpoll on regular files on *BSDs.
The kqueue based netpoller always registers file descriptors with EVFILT_READ and EVFILT_WRITE.
However only EVFILT_READ notification is supported for regular files.
On FreeBSD a regular file is always reported as ready for writing, resulting in a busy wait.
On Darwin, Dragonfly, NetBSD and OpenBSD, a regular file is reported as ready for both reading and writing only once.
Updates #19093
Change-Id: If284341f60c6c2332fb5499637d4cfa7a4e26b7b
Reviewed-on: https://go-review.googlesource.com/c/156379
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
-rw-r--r-- | src/os/file_unix.go | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/src/os/file_unix.go b/src/os/file_unix.go index 688b68e1c3..c91efa8185 100644 --- a/src/os/file_unix.go +++ b/src/os/file_unix.go @@ -117,23 +117,29 @@ func newFile(fd uintptr, name string, kind newFileKind) *File { pollable := kind == kindOpenFile || kind == kindPipe || kind == kindNonBlock - // Don't try to use kqueue with regular files on FreeBSD. - // It crashes the system unpredictably while running all.bash. - // Issue 19093. // If the caller passed a non-blocking filedes (kindNonBlock), // we assume they know what they are doing so we allow it to be // used with kqueue. - if runtime.GOOS == "freebsd" && kind == kindOpenFile { - pollable = false - } - - // On Darwin, kqueue does not work properly with fifos: - // closing the last writer does not cause a kqueue event - // for any readers. See issue #24164. - if runtime.GOOS == "darwin" && kind == kindOpenFile { + if kind == kindOpenFile { var st syscall.Stat_t - if err := syscall.Fstat(fdi, &st); err == nil && st.Mode&syscall.S_IFMT == syscall.S_IFIFO { - pollable = false + switch runtime.GOOS { + // Don't try to use kqueue with regular files on *BSDs. + // on FreeBSD with older kernels it used to crash the system unpredictably while running all.bash. + // while with newer kernels a regular file is always reported as ready for writing. + // on Dragonfly, NetBSD and OpenBSD the fd is signaled only once as ready (both read and write). + // Issue 19093. + case "dragonfly", "freebsd", "netbsd", "openbsd": + if err := syscall.Fstat(fdi, &st); err == nil && st.Mode&syscall.S_IFMT == syscall.S_IFREG { + pollable = false + } + case "darwin": + // In addition to the behavior described above for regular files, + // on Darwin, kqueue does not work properly with fifos: + // closing the last writer does not cause a kqueue event + // for any readers. See issue #24164. + if err := syscall.Fstat(fdi, &st); err == nil && (st.Mode&syscall.S_IFMT == syscall.S_IFIFO || st.Mode&syscall.S_IFMT == syscall.S_IFREG) { + pollable = false + } } } |