diff options
Diffstat (limited to 'vendor/golang.org/x/sys/unix/affinity_linux.go')
| -rw-r--r-- | vendor/golang.org/x/sys/unix/affinity_linux.go | 131 |
1 files changed, 118 insertions, 13 deletions
diff --git a/vendor/golang.org/x/sys/unix/affinity_linux.go b/vendor/golang.org/x/sys/unix/affinity_linux.go index 3c7a6d6..acd6257 100644 --- a/vendor/golang.org/x/sys/unix/affinity_linux.go +++ b/vendor/golang.org/x/sys/unix/affinity_linux.go @@ -13,11 +13,19 @@ import ( const cpuSetSize = _CPU_SETSIZE / _NCPUBITS -// CPUSet represents a CPU affinity mask. +// CPUSet represents a bit mask of CPUs, to be used with [SchedGetaffinity], [SchedSetaffinity], +// and [SetMemPolicy]. +// +// Note this type can only represent CPU IDs 0 through 1023. +// Use [CPUSetDynamic]/[NewCPUSet] instead to avoid this limit. type CPUSet [cpuSetSize]cpuMask -func schedAffinity(trap uintptr, pid int, set *CPUSet) error { - _, _, e := RawSyscall(trap, uintptr(pid), uintptr(unsafe.Sizeof(*set)), uintptr(unsafe.Pointer(set))) +// CPUSetDynamic represents a bit mask of CPUs, to be used with [SchedGetaffinityDynamic], +// [SchedSetaffinityDynamic], and [SetMemPolicyDynamic]. Use [NewCPUSet] to allocate. +type CPUSetDynamic []cpuMask + +func schedAffinity(trap uintptr, pid int, size uintptr, ptr unsafe.Pointer) error { + _, _, e := RawSyscall(trap, uintptr(pid), uintptr(size), uintptr(ptr)) if e != 0 { return errnoErr(e) } @@ -27,13 +35,13 @@ func schedAffinity(trap uintptr, pid int, set *CPUSet) error { // SchedGetaffinity gets the CPU affinity mask of the thread specified by pid. // If pid is 0 the calling thread is used. func SchedGetaffinity(pid int, set *CPUSet) error { - return schedAffinity(SYS_SCHED_GETAFFINITY, pid, set) + return schedAffinity(SYS_SCHED_GETAFFINITY, pid, unsafe.Sizeof(*set), unsafe.Pointer(set)) } // SchedSetaffinity sets the CPU affinity mask of the thread specified by pid. // If pid is 0 the calling thread is used. func SchedSetaffinity(pid int, set *CPUSet) error { - return schedAffinity(SYS_SCHED_SETAFFINITY, pid, set) + return schedAffinity(SYS_SCHED_SETAFFINITY, pid, unsafe.Sizeof(*set), unsafe.Pointer(set)) } // Zero clears the set s, so that it contains no CPUs. @@ -41,6 +49,13 @@ func (s *CPUSet) Zero() { clear(s[:]) } +// Fill adds all possible CPU bits to the set s. On Linux, [SchedSetaffinity] +// will silently ignore any invalid CPU bits in [CPUSet] so this is an +// efficient way of resetting the CPU affinity of a process. +func (s *CPUSet) Fill() { + cpuMaskFill(s[:]) +} + func cpuBitsIndex(cpu int) int { return cpu / _NCPUBITS } @@ -49,24 +64,27 @@ func cpuBitsMask(cpu int) cpuMask { return cpuMask(1 << (uint(cpu) % _NCPUBITS)) } -// Set adds cpu to the set s. -func (s *CPUSet) Set(cpu int) { +func cpuMaskFill(s []cpuMask) { + for i := range s { + s[i] = ^cpuMask(0) + } +} + +func cpuMaskSet(s []cpuMask, cpu int) { i := cpuBitsIndex(cpu) if i < len(s) { s[i] |= cpuBitsMask(cpu) } } -// Clear removes cpu from the set s. -func (s *CPUSet) Clear(cpu int) { +func cpuMaskClear(s []cpuMask, cpu int) { i := cpuBitsIndex(cpu) if i < len(s) { s[i] &^= cpuBitsMask(cpu) } } -// IsSet reports whether cpu is in the set s. -func (s *CPUSet) IsSet(cpu int) bool { +func cpuMaskIsSet(s []cpuMask, cpu int) bool { i := cpuBitsIndex(cpu) if i < len(s) { return s[i]&cpuBitsMask(cpu) != 0 @@ -74,11 +92,98 @@ func (s *CPUSet) IsSet(cpu int) bool { return false } -// Count returns the number of CPUs in the set s. -func (s *CPUSet) Count() int { +func cpuMaskCount(s []cpuMask) int { c := 0 for _, b := range s { c += bits.OnesCount64(uint64(b)) } return c } + +// Set adds cpu to the set s. If cpu is out of bounds for s, no action is taken. +func (s *CPUSet) Set(cpu int) { + cpuMaskSet(s[:], cpu) +} + +// Clear removes cpu from the set s. If cpu is out of bounds for s, no action is taken. +func (s *CPUSet) Clear(cpu int) { + cpuMaskClear(s[:], cpu) +} + +// IsSet reports whether cpu is in the set s. +func (s *CPUSet) IsSet(cpu int) bool { + return cpuMaskIsSet(s[:], cpu) +} + +// Count returns the number of CPUs in the set s. +func (s *CPUSet) Count() int { + return cpuMaskCount(s[:]) +} + +// NewCPUSet creates a CPU affinity mask capable of representing CPU IDs +// up to maxCPU (exclusive). +func NewCPUSet(maxCPU int) CPUSetDynamic { + numMasks := (maxCPU + _NCPUBITS - 1) / _NCPUBITS + if numMasks == 0 { + numMasks = 1 + } + return make(CPUSetDynamic, numMasks) +} + +// Zero clears the set s, so that it contains no CPUs. +func (s CPUSetDynamic) Zero() { + clear(s) +} + +// Fill adds all possible CPU bits to the set s. On Linux, [SchedSetaffinityDynamic] +// will silently ignore any invalid CPU bits in [CPUSetDynamic] so this is an +// efficient way of resetting the CPU affinity of a process. +func (s CPUSetDynamic) Fill() { + cpuMaskFill(s) +} + +// Set adds cpu to the set s. If cpu is out of bounds for s, no action is taken. +func (s CPUSetDynamic) Set(cpu int) { + cpuMaskSet(s, cpu) +} + +// Clear removes cpu from the set s. If cpu is out of bounds for s, no action is taken. +func (s CPUSetDynamic) Clear(cpu int) { + cpuMaskClear(s, cpu) +} + +// IsSet reports whether cpu is in the set s. +func (s CPUSetDynamic) IsSet(cpu int) bool { + return cpuMaskIsSet(s, cpu) +} + +// Count returns the number of CPUs in the set s. +func (s CPUSetDynamic) Count() int { + return cpuMaskCount(s) +} + +func (s CPUSetDynamic) size() uintptr { + return uintptr(len(s)) * unsafe.Sizeof(cpuMask(0)) +} + +func (s CPUSetDynamic) pointer() unsafe.Pointer { + if len(s) == 0 { + return nil + } + return unsafe.Pointer(&s[0]) +} + +// SchedGetaffinityDynamic gets the CPU affinity mask of the thread specified by pid. +// If pid is 0 the calling thread is used. +// +// If the set is smaller than the size of the affinity mask used by the kernel, +// [EINVAL] is returned. +func SchedGetaffinityDynamic(pid int, set CPUSetDynamic) error { + return schedAffinity(SYS_SCHED_GETAFFINITY, pid, set.size(), set.pointer()) +} + +// SchedSetaffinityDynamic sets the CPU affinity mask of the thread specified by pid. +// If pid is 0 the calling thread is used. +func SchedSetaffinityDynamic(pid int, set CPUSetDynamic) error { + return schedAffinity(SYS_SCHED_SETAFFINITY, pid, set.size(), set.pointer()) +} |
