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2025-09-18runtime: use futexes with 64-bit time on LinuxDaniel Maslowski
Linux introduced new syscalls to fix the year 2038 issue. To still be able to use the old ones, the Kconfig option COMPAT_32BIT_TIME would be necessary. Use the new syscall with 64-bit values for futex by default. Define _ENOSYS for detecting if it's not available. Add a fallback to use the older syscall in case the new one is not available, since Go runs on Linux from 2.6.32 on, per https://go.dev/wiki/MinimumRequirements. Updates #75133 Change-Id: I65daff0a3d06b55440ff05d8f5a9aa1c07eb201d GitHub-Last-Rev: 96dd1bd84bd12d898e971157fc83da562cc4f6b4 GitHub-Pull-Request: golang/go#75306 Reviewed-on: https://go-review.googlesource.com/c/go/+/701615 Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Mark Freeman <markfreeman@google.com> Reviewed-by: Jorropo <jorropo.pgm@gmail.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2022-10-07runtime: move epoll syscalls to runtime/internal/syscallAndrew Pogrebnoy
This change moves Linux epoll's syscalls implementation to the "runtime/internal/syscall" package. The intention in this CL was to minimise behavioural changes but make the code more generalised. This also will allow adding new syscalls (like epoll_pwait2) without the need to implement assembly stubs for each arch. It also drops epoll_create as not all architectures provide this call. epoll_create1 was added to the kernel in version 2.6.27 and Go requires Linux kernel version 2.6.32 or later since Go 1.18. So it is safe to always use epoll_create1. This is a resubmit as the previous CL 421994 was reverted due to test failures after the merge with the master. The issue was fixed in CL 438615 For #53824 For #51087 Change-Id: I1bd0f23a85b4f9b80178c5dd36fd3e95ff4f9648 Reviewed-on: https://go-review.googlesource.com/c/go/+/440115 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: Michael Pratt <mpratt@google.com>
2022-09-30Revert "runtime: move epoll syscalls to runtime/internal/syscall"Michael Pratt
This reverts CL 421994. Reason for revert: breaks runtime.TestCheckPtr2 For #53824 For #51087 Change-Id: I044ea4d6efdffe0a4b7fb0d2bb3717d9f391fc59 Reviewed-on: https://go-review.googlesource.com/c/go/+/437295 TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Michael Pratt <mpratt@google.com> Auto-Submit: Michael Pratt <mpratt@google.com> Reviewed-by: Bryan Mills <bcmills@google.com>
2022-09-30runtime: move epoll syscalls to runtime/internal/syscallAndrew Pogrebnoy
This change moves Linux epoll's syscalls implementation to the "runtime/internal/syscall" package. The intention in this CL was to minimise behavioural changes but make the code more generalised. This also will allow adding new syscalls (like epoll_pwait2) without the need to implement assembly stubs for each arch. It also drops epoll_create as not all architectures provide this call. epoll_create1 was added to the kernel in version 2.6.27 and Go requires Linux kernel version 2.6.32 or later since Go 1.18. So it is safe to always use epoll_create1. For #53824 For #51087 Change-Id: I9a6a26b7f2075a38e041de1bab4691da0ecb94fc Reviewed-on: https://go-review.googlesource.com/c/go/+/421994 Reviewed-by: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Run-TryBot: Michael Pratt <mpratt@google.com> Auto-Submit: Michael Pratt <mpratt@google.com>
2022-03-03runtime: remove fallback to pipe on platforms with pipe2Tobias Klauser
On Linux, the minimum required kernel version for Go 1.18 was be changed to 2.6.32, see #45964. The pipe2 syscall was added in 2.6.27. All other platforms already provide the pipe2 syscall in the minimum supported version: - DragonFly BSD added it in version 4.2, see https://www.dragonflybsd.org/release42/ - FreeBSD added it in version 10.0, see https://www.freebsd.org/cgi/man.cgi?pipe(2)#end - NetBSD added it in version 6.0, see https://man.netbsd.org/pipe2.2#HISTORY - OpenBSD added it in version 5.7, see https://man.openbsd.org/pipe.2#HISTORY - Illumos supports it since 2013, see https://www.illumos.org/issues/3714 - Solaris supports it since 11.4 This also allows to remove setNonblock which was only used in the pipe fallback path on these platforms. Change-Id: I1f40d32fd3065d74e22af77b9ff2292b9cf66706 Reviewed-on: https://go-review.googlesource.com/c/go/+/389354 Trust: Tobias Klauser <tobias.klauser@gmail.com> Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2022-02-15runtime, syscall: reimplement AllThreadsSyscall using only signals.Michael Pratt
In issue 50113, we see that a thread blocked in a system call can result in a hang of AllThreadsSyscall. To resolve this, we must send a signal to these threads to knock them out of the system call long enough to run the per-thread syscall. Stepping back, if we need to send signals anyway, it should be possible to implement this entire mechanism on top of signals. This CL does so, vastly simplifying the mechanism, both as a direct result of newly-unnecessary code as well as some ancillary simplifications to make things simpler to follow. Major changes: * The rest of the mechanism is moved to os_linux.go, with fields in mOS instead of m itself. * 'Fixup' fields and functions are renamed to 'perThreadSyscall' so they are more precise about their purpose. * Rather than getting passed a closure, doAllThreadsSyscall takes the syscall number and arguments. This avoids a lot of hairy behavior: * The closure may potentially only be live in fields in the M, hidden from the GC. Not necessary with no closure. * The need to loan out the race context. A direct RawSyscall6 call does not require any race context. * The closure previously conditionally panicked in strange locations, like a signal handler. Now we simply throw. * All manual fixup synchronization with mPark, sysmon, templateThread, sigqueue, etc is gone. The core approach is much simpler: doAllThreadsSyscall sends a signal to every thread in allm, which executes the system call from the signal handler. We use (SIGRTMIN + 1), aka SIGSETXID, the same signal used by glibc for this purpose. As such, we are careful to only handle this signal on non-cgo binaries. Synchronization with thread creation is a key part of this CL. The comment near the top of doAllThreadsSyscall describes the required synchronization semantics and how they are achieved. Note that current use of allocmLock protects the state mutations of allm that are also protected by sched.lock. allocmLock is used instead of sched.lock simply to avoid holding sched.lock for so long. Fixes #50113 Change-Id: Ic7ea856dc66cf711731540a54996e08fc986ce84 Reviewed-on: https://go-review.googlesource.com/c/go/+/383434 Reviewed-by: Austin Clements <austin@google.com> Trust: Michael Pratt <mpratt@google.com> Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2021-10-28all: go fix -fix=buildtag std cmd (except for bootstrap deps, vendor)Russ Cox
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>
2021-09-27runtime: add timer_create syscalls for LinuxRhys Hiltner
Updates #35057 Change-Id: Id702b502fa4e4005ba1e450a945bc4420a8a8b8c Reviewed-on: https://go-review.googlesource.com/c/go/+/342052 Run-TryBot: Rhys Hiltner <rhys@justin.tv> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Trust: Than McIntosh <thanm@google.com>
2021-02-20all: go fmt std cmd (but revert vendor)Russ Cox
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>
2019-10-25runtime: fix typo of MADV_NOHUGEPAGEMeng Zhuo
Change-Id: I60a1ca606fe7492c05697c4d58afc7f19fcc63fe Reviewed-on: https://go-review.googlesource.com/c/go/+/203340 Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com> Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-10-20runtime: define nonblockingPipeIan Lance Taylor
This requires defining pipe, pipe2, and setNonblock for various platforms. The new function is currently only used on AIX. It will be used by later CLs in this series. Updates #27707 Change-Id: Id2f987b66b4c66a3ef40c22484ff1d14f58e9b31 Reviewed-on: https://go-review.googlesource.com/c/go/+/171822 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-09-18runtime: use MADV_FREE on Linux if availableTobias Klauser
On Linux, sysUnused currently uses madvise(MADV_DONTNEED) to signal the kernel that a range of allocated memory contains unneeded data. After a successful call, the range (but not the data it contained before the call to madvise) is still available but the first access to that range will unconditionally incur a page fault (needed to 0-fill the range). A faster alternative is MADV_FREE, available since Linux 4.5. The mechanism is very similar, but the page fault will only be incurred if the kernel, between the call to madvise and the first access, decides to reuse that memory for something else. In sysUnused, test whether MADV_FREE is supported and fall back to MADV_DONTNEED in case it isn't. This requires making the return value of the madvise syscall available to the caller, so change runtime.madvise to return it. Fixes #23687 Change-Id: I962c3429000dd9f4a00846461ad128b71201bb04 Reviewed-on: https://go-review.googlesource.com/135395 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2014-10-22build: merge the great pkg/ rename into dev.power64Austin Clements
This also removes pkg/runtime/traceback_lr.c, which was ported to Go in an earlier commit and then moved to runtime/traceback.go. Reviewer: rsc@golang.org rsc: LGTM
2014-09-08build: move package sources from src/pkg to srcRuss Cox
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.