From 93f059947e31e8dda98c98880aee0e7b924d9a61 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Tue, 27 Aug 2019 06:46:16 -0600 Subject: [PATCH] [release-branch.go1.12] runtime: monitor for suspend/resume to kick timeouts Starting in Windows 8, the wait functions don't take into account suspend time, even though the monotonic counters do. This results in timer buckets stalling on resume. Therefore, this commit makes it so that on resume, we return from the wait functions and recalculate the amount of time left to wait. This is a cherry pick of CL 191957 and its cleanup, CL 198417. Updates #31528 Fixes #36376 Change-Id: I0db02cc72188cb620954e87a0180e0a3c83f4a56 Reviewed-on: https://go-review.googlesource.com/c/go/+/193607 Run-TryBot: Jason A. Donenfeld TryBot-Result: Gobot Gobot Reviewed-by: Austin Clements Reviewed-on: https://go-review.googlesource.com/c/go/+/213197 --- src/runtime/os_windows.go | 81 ++++++++++++++++++++++++++++++---- src/runtime/syscall_windows.go | 12 +++-- 2 files changed, 80 insertions(+), 13 deletions(-) diff --git a/src/runtime/os_windows.go b/src/runtime/os_windows.go index d3e84fe3dcbf2b..a3292c427bec3d 100644 --- a/src/runtime/os_windows.go +++ b/src/runtime/os_windows.go @@ -49,6 +49,7 @@ const ( //go:cgo_import_dynamic runtime._VirtualFree VirtualFree%3 "kernel32.dll" //go:cgo_import_dynamic runtime._VirtualQuery VirtualQuery%3 "kernel32.dll" //go:cgo_import_dynamic runtime._WaitForSingleObject WaitForSingleObject%2 "kernel32.dll" +//go:cgo_import_dynamic runtime._WaitForMultipleObjects WaitForMultipleObjects%4 "kernel32.dll" //go:cgo_import_dynamic runtime._WriteConsoleW WriteConsoleW%5 "kernel32.dll" //go:cgo_import_dynamic runtime._WriteFile WriteFile%5 "kernel32.dll" @@ -96,6 +97,7 @@ var ( _VirtualFree, _VirtualQuery, _WaitForSingleObject, + _WaitForMultipleObjects, _WriteConsoleW, _WriteFile, _ stdFunction @@ -138,7 +140,8 @@ func tstart_stdcall(newm *m) uint32 func ctrlhandler(_type uint32) uint32 type mOS struct { - waitsema uintptr // semaphore for parking on locks + waitsema uintptr // semaphore for parking on locks + resumesema uintptr // semaphore to indicate suspend/resume } //go:linkname os_sigpipe os.sigpipe @@ -257,6 +260,40 @@ func loadOptionalSyscalls() { } } +func monitorSuspendResume() { + const _DEVICE_NOTIFY_CALLBACK = 2 + type _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS struct { + callback uintptr + context uintptr + } + + powrprof := windowsLoadSystemLib([]byte("powrprof.dll\000")) + if powrprof == 0 { + return // Running on Windows 7, where we don't need it anyway. + } + powerRegisterSuspendResumeNotification := windowsFindfunc(powrprof, []byte("PowerRegisterSuspendResumeNotification\000")) + if powerRegisterSuspendResumeNotification == nil { + return // Running on Windows 7, where we don't need it anyway. + } + var fn interface{} = func(context uintptr, changeType uint32, setting uintptr) uintptr { + for mp := (*m)(atomic.Loadp(unsafe.Pointer(&allm))); mp != nil; mp = mp.alllink { + if mp.resumesema != 0 { + stdcall1(_SetEvent, mp.resumesema) + } + } + return 0 + } + params := _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS{ + callback: compileCallback(*efaceOf(&fn), true), + } + handle := uintptr(0) + if stdcall3(powerRegisterSuspendResumeNotification, _DEVICE_NOTIFY_CALLBACK, + uintptr(unsafe.Pointer(¶ms)), + uintptr(unsafe.Pointer(&handle))) != 0 { + throw("PowerRegisterSuspendResumeNotification failure") + } +} + //go:nosplit func getLoadLibrary() uintptr { return uintptr(unsafe.Pointer(_LoadLibraryW)) @@ -487,6 +524,10 @@ func goenvs() { } stdcall1(_FreeEnvironmentStringsW, uintptr(strings)) + + // We call this all the way here, late in init, so that malloc works + // for the callback function this generates. + monitorSuspendResume() } // exiting is set to non-zero when the process is exiting. @@ -605,19 +646,32 @@ func semasleep(ns int64) int32 { _WAIT_FAILED = 0xFFFFFFFF ) - // store ms in ns to save stack space + var result uintptr if ns < 0 { - ns = _INFINITE + result = stdcall2(_WaitForSingleObject, getg().m.waitsema, uintptr(_INFINITE)) } else { - ns = int64(timediv(ns, 1000000, nil)) - if ns == 0 { - ns = 1 + start := nanotime() + elapsed := int64(0) + for { + ms := int64(timediv(ns-elapsed, 1000000, nil)) + if ms == 0 { + ms = 1 + } + result = stdcall4(_WaitForMultipleObjects, 2, + uintptr(unsafe.Pointer(&[2]uintptr{getg().m.waitsema, getg().m.resumesema})), + 0, uintptr(ms)) + if result != _WAIT_OBJECT_0+1 { + // Not a suspend/resume event + break + } + elapsed = nanotime() - start + if elapsed >= ns { + return -1 + } } } - - result := stdcall2(_WaitForSingleObject, getg().m.waitsema, uintptr(ns)) switch result { - case _WAIT_OBJECT_0: //signaled + case _WAIT_OBJECT_0: // Signaled return 0 case _WAIT_TIMEOUT: @@ -666,6 +720,15 @@ func semacreate(mp *m) { throw("runtime.semacreate") }) } + mp.resumesema = stdcall4(_CreateEventA, 0, 0, 0, 0) + if mp.resumesema == 0 { + systemstack(func() { + print("runtime: createevent failed; errno=", getlasterror(), "\n") + throw("runtime.semacreate") + }) + stdcall1(_CloseHandle, mp.waitsema) + mp.waitsema = 0 + } } // May run with m.p==nil, so write barriers are not allowed. This diff --git a/src/runtime/syscall_windows.go b/src/runtime/syscall_windows.go index 36ad7511af86b5..920468286b9688 100644 --- a/src/runtime/syscall_windows.go +++ b/src/runtime/syscall_windows.go @@ -74,16 +74,18 @@ func compileCallback(fn eface, cleanstack bool) (code uintptr) { argsize += uintptrSize } - lock(&cbs.lock) - defer unlock(&cbs.lock) + lock(&cbs.lock) // We don't unlock this in a defer because this is used from the system stack. n := cbs.n for i := 0; i < n; i++ { if cbs.ctxt[i].gobody == fn.data && cbs.ctxt[i].isCleanstack() == cleanstack { - return callbackasmAddr(i) + r := callbackasmAddr(i) + unlock(&cbs.lock) + return r } } if n >= cb_max { + unlock(&cbs.lock) throw("too many callback functions") } @@ -99,7 +101,9 @@ func compileCallback(fn eface, cleanstack bool) (code uintptr) { cbs.ctxt[n] = c cbs.n++ - return callbackasmAddr(n) + r := callbackasmAddr(n) + unlock(&cbs.lock) + return r } const _LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800