diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-08-31 21:33:58 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-09-27 11:57:30 +0200 |
| commit | c265e976f4669fd65f5b47e6865f50d1cb66bd02 (patch) | |
| tree | b80f5c8500bd6ad92ee0474bce2b4186dd2540c5 /include/qom/cpu.h | |
| parent | 3359baad36889b83df40b637ed993a4b816c4906 (diff) | |
cpus-common: lock-free fast path for cpu_exec_start/end
Set cpu->running without taking the cpu_list lock, only requiring it if
there is a concurrent exclusive section. This requires adding a new
field to CPUState, which records whether a running CPU is being counted
in pending_cpus.
When an exclusive section is started concurrently with cpu_exec_start,
cpu_exec_start can use the new field to determine if it has to wait for
the end of the exclusive section. Likewise, cpu_exec_end can use it to
see if start_exclusive is waiting for that CPU.
This a separate patch for easier bisection of issues.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/qom/cpu.h')
| -rw-r--r-- | include/qom/cpu.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/include/qom/cpu.h b/include/qom/cpu.h index 5dfe74a0e7..22b54d6d93 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -242,7 +242,8 @@ struct qemu_work_item; * @nr_threads: Number of threads within this CPU. * @numa_node: NUMA node this CPU is belonging to. * @host_tid: Host thread ID. - * @running: #true if CPU is currently running; + * @running: #true if CPU is currently running (lockless). + * @has_waiter: #true if a CPU is currently waiting for the cpu_exec_end; * valid under cpu_list_lock. * @created: Indicates whether the CPU thread has been successfully created. * @interrupt_request: Indicates a pending interrupt request. @@ -296,7 +297,7 @@ struct CPUState { #endif int thread_id; uint32_t host_tid; - bool running; + bool running, has_waiter; struct QemuCond *halt_cond; bool thread_kicked; bool created; |