Fixes#59679
Change-Id: I1334b793825a2a57d239e3c98373bf4c93cc622a
Reviewed-on: https://go-review.googlesource.com/c/go/+/522215
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Michael Pratt <mpratt@google.com>
Run-TryBot: Andy Pan <panjf2000@gmail.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
The runtime was adjusting netpollWaiters before the waiting
goroutines were marked as ready. This could cause the scheduler
to report a deadlock because there were no goroutines ready to run.
Keeping netpollWaiters non-zero ensures that at least one goroutine
will call netpoll(-1) from findRunnable.
This does mean that if a program has network activity for a while
and then never has it again, and also has no timers, then we can leave
an M stranded in a call to netpoll from which it will never return.
At least this won't be a common case. And it's not new; this has been
a potential problem for some time.
Fixes#61454
Change-Id: I17c7f891c2bb1262fda12c6929664e64686463c8
Reviewed-on: https://go-review.googlesource.com/c/go/+/511455
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Fix spelling errors discovered using https://github.com/codespell-project/codespell. Errors in data files and vendored packages are ignored.
Change-Id: I83c7818222f2eea69afbd270c15b7897678131dc
GitHub-Last-Rev: 3491615b1b
GitHub-Pull-Request: golang/go#60758
Reviewed-on: https://go-review.googlesource.com/c/go/+/502576
Auto-Submit: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
It is possible for a netpoll file to be closed and for the pollDesc
to be reused while a netpoll is running. This normally only causes
spurious wakeups, but if there is an error on the old file then the
new file can be incorrectly marked as having an error.
Fix this problem on most systems by introducing an fd sequence field
and using that as a tag in a taggedPointer. The taggedPointer is
stored in epoll or kqueue or whatever is being used. If the taggedPointer
returned by the kernel has a tag that does not match the fd
sequence field, the notification is for a closed file, and we
can ignore it. We check the tag stored in the pollDesc, and we also
check the tag stored in the pollDesc.atomicInfo.
This approach does not work on 32-bit systems where the kernel
only provides a 32-bit field to hold a user value. On those systems
we continue to use the older method without the sequence protection.
This is not ideal, but it is not an issue on Linux because the kernel
provides a 64-bit field, and it is not an issue on Windows because
there are no poller errors on Windows. It is potentially an issue
on *BSD systems, but on those systems we already call fstat in newFile
in os/file_unix.go to avoid adding non-pollable files to kqueue.
So we currently don't know of any cases that will fail.
Fixes#59545
Change-Id: I9a61e20dc39b4266a7a2978fc16446567fe683ac
Reviewed-on: https://go-review.googlesource.com/c/go/+/484837
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Orlando Labao <orlando.labao43@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Bypass: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Bypass: Ian Lance Taylor <iant@golang.org>
The netpoll code was written long ago, when the
only multiprocessors that Go ran on were x86.
It assumed that an atomic store would trigger a
full memory barrier and then used that barrier
to order otherwise racy access to a handful of fields,
including pollDesc.closing.
On ARM64, this code has finally failed, because
the atomic store is on a value completely unrelated
to any of the racily-accessed fields, and the ARMv8
hardware, unlike x86, is clever enough not to do a
full memory barrier for a simple atomic store.
We are seeing a constant background rate of trybot
failures where the net/http tests deadlock - a netpollblock
has clearly happened after the pollDesc has begun to close.
The code that does the racy reads is netpollcheckerr,
which needs to be able to run without acquiring a lock.
This CL fixes the race, without introducing unnecessary
inefficiency or deadlock, by arranging for every updater
of the relevant fields to publish a summary as a single
atomic uint32, and then having netpollcheckerr use a
single atomic load to fetch the relevant bits and then
proceed as before.
Fixes#45211 (until proven otherwise!).
Change-Id: Ib6788c8da4d00b7bda84d55ca3fdffb5a64c1a0a
Reviewed-on: https://go-review.googlesource.com/c/go/+/378234
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Trust: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When these packages are released as part of Go 1.18,
Go 1.16 will no longer be supported, so we can remove
the +build tags in these files.
Ran go fix -fix=buildtag std cmd and then reverted the bootstrapDirs
as defined in src/cmd/dist/buildtool.go, which need to continue
to build with Go 1.4 for now.
Also reverted src/vendor and src/cmd/vendor, which will need
to be updated in their own repos first.
Manual changes in runtime/pprof/mprof_test.go to adjust line numbers.
For #41184.
Change-Id: Ic0f93f7091295b6abc76ed5cd6e6746e1280861e
Reviewed-on: https://go-review.googlesource.com/c/go/+/344955
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Make all our package sources use Go 1.17 gofmt format
(adding //go:build lines).
Part of //go:build change (#41184).
See https://golang.org/design/draft-gobuild
Change-Id: Ia0534360e4957e58cd9a18429c39d0e32a6addb4
Reviewed-on: https://go-review.googlesource.com/c/go/+/294430
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
There's no need for netpollWakeSig to use a uintptr type, a uint32 is enough.
Relevant CL: CL 212737
Change-Id: Ide24478b217a02bad62f7e000a9680c26a8c5366
Reviewed-on: https://go-review.googlesource.com/c/go/+/227798
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
There might be some concurrent (maybe not concurrent, just sequential but in a short time window) and duplicate calls to `netpollBreak`, trying to wake up a net-poller. If one has called `netpollBreak` and that waking event hasn't been received by epollwait/kevent/..., then the subsequent calls of `netpollBreak` ought to be ignored or in other words, these calls should be converged into one.
Benchmarks go1.13.5 darwin/amd64:
benchmark-func time/op (old) time/op (new) delta
BenchmarkNetpollBreak-4 29668ns ±1% 3131ns ±2% -89.45%
mem/B (old) mem/B (new) delta
154B ±13% 0B ±0% -100%
Change-Id: I3cf757a5d6edc5a99adad7aea3baee4b7f2a8f5c
GitHub-Last-Rev: 15bcfbab8a
GitHub-Pull-Request: golang/go#36294
Reviewed-on: https://go-review.googlesource.com/c/go/+/212737
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Report the value returned by kevent, not the previously set errno which
is 0.
Found while debugging CL 198544
Change-Id: I854f5418f8ed8e083d909d328501355496c67a53
Reviewed-on: https://go-review.googlesource.com/c/go/+/202777
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The new netpollBreak function can be used to interrupt a blocking netpoll.
This function is not currently used; it will be used by later CLs.
Updates #27707
Change-Id: I5cb936609ba13c3c127ea1368a49194fc58c9f4d
Reviewed-on: https://go-review.googlesource.com/c/go/+/171824
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This new facility will be used by future CLs in this series.
Change the only blocking call to netpoll to do the right thing when
netpoll returns an empty list.
Updates #6239
Updates #27707
Change-Id: I58b3c2903eda61a3698b1a4729ed0e81382bb1ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/171821
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
This change makes the runtime-integrated network poller report only
critical event scanning errors.
In the previous attempt, CL 166497, we treated any combination of error
events as event scanning errors and it caused false positives in event
waiters because platform-dependent event notification mechanisms allow
event originators to use various combination of events.
To avoid false positives, this change makes the poller treat an
individual error event as a critical event scanning error by the
convention of event notification mechanism implementations.
Updates #30624.
Fixes#30817.
Fixes#30840.
Change-Id: I906c9e83864527ff73f636fd02bab854d54684ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/167777
Run-TryBot: Mikio Hara <mikioh.public.networking@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change makes it possible the runtime-integrated network poller and
APIs in the package internal/poll to report an event scanning error on a
read event.
The latest Go releases open up the way of the manipulation of the poller
for users. On the other hand, it starts misleading users into believing
that the poller accepts any user-configured file or socket perfectly
because of not reporting any error on event scanning, as mentioned in
issue 30426. The initial implementation of the poller was designed for
just well-configured, validated sockets produced by the package net.
However, the assumption is now obsolete.
Fixes#30624.
Benchmark results on linux/amd64:
benchmark old ns/op new ns/op delta
BenchmarkTCP4OneShot-4 24649 23979 -2.72%
BenchmarkTCP4OneShotTimeout-4 25742 24411 -5.17%
BenchmarkTCP4Persistent-4 5139 5222 +1.62%
BenchmarkTCP4PersistentTimeout-4 4919 4892 -0.55%
BenchmarkTCP6OneShot-4 21182 20767 -1.96%
BenchmarkTCP6OneShotTimeout-4 23364 22305 -4.53%
BenchmarkTCP6Persistent-4 4351 4366 +0.34%
BenchmarkTCP6PersistentTimeout-4 4227 4255 +0.66%
BenchmarkTCP4ConcurrentReadWrite-4 2309 1839 -20.36%
BenchmarkTCP6ConcurrentReadWrite-4 2180 1791 -17.84%
benchmark old allocs new allocs delta
BenchmarkTCP4OneShot-4 26 26 +0.00%
BenchmarkTCP4OneShotTimeout-4 26 26 +0.00%
BenchmarkTCP4Persistent-4 0 0 +0.00%
BenchmarkTCP4PersistentTimeout-4 0 0 +0.00%
BenchmarkTCP6OneShot-4 26 26 +0.00%
BenchmarkTCP6OneShotTimeout-4 26 26 +0.00%
BenchmarkTCP6Persistent-4 0 0 +0.00%
BenchmarkTCP6PersistentTimeout-4 0 0 +0.00%
BenchmarkTCP4ConcurrentReadWrite-4 0 0 +0.00%
BenchmarkTCP6ConcurrentReadWrite-4 0 0 +0.00%
benchmark old bytes new bytes delta
BenchmarkTCP4OneShot-4 2000 2000 +0.00%
BenchmarkTCP4OneShotTimeout-4 2000 2000 +0.00%
BenchmarkTCP4Persistent-4 0 0 +0.00%
BenchmarkTCP4PersistentTimeout-4 0 0 +0.00%
BenchmarkTCP6OneShot-4 2144 2144 +0.00%
BenchmarkTCP6OneShotTimeout-4 2144 2145 +0.05%
BenchmarkTCP6Persistent-4 0 0 +0.00%
BenchmarkTCP6PersistentTimeout-4 0 0 +0.00%
BenchmarkTCP4ConcurrentReadWrite-4 0 0 +0.00%
BenchmarkTCP6ConcurrentReadWrite-4 0 0 +0.00%
Change-Id: Iab60e504dff5639e688dc5420d852f336508c0af
Reviewed-on: https://go-review.googlesource.com/c/go/+/166497
Run-TryBot: Mikio Hara <mikioh.public.networking@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
netpoll is perhaps one of the most confusing uses of G lists currently
since it passes around many lists as bare *g values right now.
Switching to gList makes it much clearer what's an individual g and
what's a list.
Change-Id: I8d8993c4967c5bae049c7a094aad3a657928ba6c
Reviewed-on: https://go-review.googlesource.com/129397
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
kqueue, kevent, closeonexec, setitimer, with sysctl and fcntl helpers.
TODO:arm,arm64
Change-Id: I9386f377186d6ac7cb99064c524a67e0c8282eba
Reviewed-on: https://go-review.googlesource.com/118561
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
On systems that use kqueue, we always register descriptors for both
EVFILT_READ and EVFILT_WRITE. On at least FreeBSD and OpenBSD, when
the write end of a pipe is registered for EVFILT_READ and EVFILT_WRITE
events, and the read end of the pipe is closed, kqueue reports an
EVFILT_READ event with EV_EOF set, but does not report an EVFILT_WRITE
event. Since the write to the pipe is waiting for an EVFILT_WRITE
event, closing the read end of a pipe can cause the write end to hang
rather than attempt another write which will fail with EPIPE.
Fix this by treating EVFILT_READ with EV_EOF set as making both reads
and writes ready to proceed.
The real test for this is in CL 71770, which tests using various
timeouts with pipes.
Updates #22114
Change-Id: Ib23fbaaddbccd8eee77bdf18f27a7f0aa50e2742
Reviewed-on: https://go-review.googlesource.com/71973
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This changes the os package to use the runtime poller for file I/O
where possible. When a system call blocks on a pollable descriptor,
the goroutine will be blocked on the poller but the thread will be
released to run other goroutines. When using a non-pollable
descriptor, the os package will continue to use thread-blocking system
calls as before.
For example, on GNU/Linux, the runtime poller uses epoll. epoll does
not support ordinary disk files, so they will continue to use blocking
I/O as before. The poller will be used for pipes.
Since this means that the poller is used for many more programs, this
modifies the runtime to only block waiting for the poller if there is
some goroutine that is waiting on the poller. Otherwise, there is no
point, as the poller will never make any goroutine ready. This
preserves the runtime's current simple deadlock detection.
This seems to crash FreeBSD systems, so it is disabled on FreeBSD.
This is issue 19093.
Using the poller on Windows requires opening the file with
FILE_FLAG_OVERLAPPED. We should only do that if we can remove that
flag if the program calls the Fd method. This is issue 19098.
Update #6817.
Update #7903.
Update #15021.
Update #18507.
Update #19093.
Update #19098.
Change-Id: Ia5197dcefa7c6fbcca97d19a6f8621b2abcbb1fe
Reviewed-on: https://go-review.googlesource.com/36800
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The current code prints an error message and then tries to carry on.
This is not helpful for Go users: they see a message that means
nothing and that they can do nothing about. In the only known case of
this message, in issue 11498, the best guess is that the netpoll code
went into an infinite loop. Instead of doing that, crash the program.
Fixes#11498.
Change-Id: Idda3456c5b708f0df6a6b56c5bb4e796bbc39d7c
Reviewed-on: https://go-review.googlesource.com/12047
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
This CL revises CL 7504 to use explicitly uintptr types for the
struct fields that are going to be updated sometimes without
write barriers. The result is that the fields are now updated *always*
without write barriers.
This approach has two important properties:
1) Now the GC never looks at the field, so if the missing reference
could cause a problem, it will do so all the time, not just when the
write barrier is missed at just the right moment.
2) Now a write barrier never happens for the field, avoiding the
(correct) detection of inconsistent write barriers when GODEBUG=wbshadow=1.
Change-Id: Iebd3962c727c0046495cc08914a8dc0808460e0e
Reviewed-on: https://go-review.googlesource.com/9019
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Rename "gothrow" to "throw" now that the C version of "throw"
is no longer needed.
This change is purely mechanical except in panic.go where the
old version of "throw" has been deleted.
sed -i "" 's/[[:<:]]gothrow[[:>:]]/throw/g' runtime/*.go
Change-Id: Icf0752299c35958b92870a97111c67bcd9159dc3
Reviewed-on: https://go-review.googlesource.com/2150
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Andy Pan
Ian Lance Taylor
Alexander Yastrebov
Cuong Manh Le
Russ Cox
Tobias Klauser
Mikio Hara
Austin Clements
Keith Randall
Mikio Hara
Brad Fitzpatrick