| Message ID | 1467839703-11733-8-git-send-email-sergey.fedorov@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Sergey Fedorov <sergey.fedorov@linaro.org> writes: > From: Sergey Fedorov <serge.fdrv@gmail.com> > > A single variable 'pending_cpus' was used for both counting currently > running CPUs and for signalling the pending exclusive operation request. > > To prepare for supporting operations which requires a quiescent state, > like translation buffer flush, it is useful to keep a counter of > currently running CPUs always up to date. > > Use a separate variable 'tcg_pending_threads' to count for currently > running CPUs and a separate variable 'exclusive_pending' to indicate > that there's an exclusive operation pending. > > Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com> > Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org> > --- > > Changes in v2: > - Rename 'tcg_pending_cpus' to 'tcg_pending_threads' Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > > --- > linux-user/main.c | 24 ++++++++++++------------ > 1 file changed, 12 insertions(+), 12 deletions(-) > > diff --git a/linux-user/main.c b/linux-user/main.c > index bdbda693cc5f..5ff0b20bad89 100644 > --- a/linux-user/main.c > +++ b/linux-user/main.c > @@ -112,7 +112,8 @@ static QemuMutex cpu_list_mutex; > static QemuMutex exclusive_lock; > static QemuCond exclusive_cond; > static QemuCond exclusive_resume; > -static int pending_cpus; > +static bool exclusive_pending; > +static int tcg_pending_threads; > > void qemu_init_cpu_loop(void) > { > @@ -142,7 +143,8 @@ void fork_end(int child) > QTAILQ_REMOVE(&cpus, cpu, node); > } > } > - pending_cpus = 0; > + tcg_pending_threads = 0; > + exclusive_pending = false; > qemu_mutex_init(&exclusive_lock); > qemu_mutex_init(&cpu_list_mutex); > qemu_cond_init(&exclusive_cond); > @@ -159,7 +161,7 @@ void fork_end(int child) > must be held. */ > static inline void exclusive_idle(void) > { > - while (pending_cpus) { > + while (exclusive_pending) { > qemu_cond_wait(&exclusive_resume, &exclusive_lock); > } > } > @@ -173,15 +175,14 @@ static inline void start_exclusive(void) > qemu_mutex_lock(&exclusive_lock); > exclusive_idle(); > > - pending_cpus = 1; > + exclusive_pending = true; > /* Make all other cpus stop executing. */ > CPU_FOREACH(other_cpu) { > if (other_cpu->running) { > - pending_cpus++; > cpu_exit(other_cpu); > } > } > - if (pending_cpus > 1) { > + while (tcg_pending_threads) { > qemu_cond_wait(&exclusive_cond, &exclusive_lock); > } > } > @@ -189,7 +190,7 @@ static inline void start_exclusive(void) > /* Finish an exclusive operation. */ > static inline void __attribute__((unused)) end_exclusive(void) > { > - pending_cpus = 0; > + exclusive_pending = false; > qemu_cond_broadcast(&exclusive_resume); > qemu_mutex_unlock(&exclusive_lock); > } > @@ -200,6 +201,7 @@ static inline void cpu_exec_start(CPUState *cpu) > qemu_mutex_lock(&exclusive_lock); > exclusive_idle(); > cpu->running = true; > + tcg_pending_threads++; > qemu_mutex_unlock(&exclusive_lock); > } > > @@ -208,11 +210,9 @@ static inline void cpu_exec_end(CPUState *cpu) > { > qemu_mutex_lock(&exclusive_lock); > cpu->running = false; > - if (pending_cpus > 1) { > - pending_cpus--; > - if (pending_cpus == 1) { > - qemu_cond_signal(&exclusive_cond); > - } > + tcg_pending_threads--; > + if (!tcg_pending_threads) { > + qemu_cond_signal(&exclusive_cond); > } > exclusive_idle(); > qemu_mutex_unlock(&exclusive_lock); -- Alex Bennée
diff --git a/linux-user/main.c b/linux-user/main.c index bdbda693cc5f..5ff0b20bad89 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -112,7 +112,8 @@ static QemuMutex cpu_list_mutex; static QemuMutex exclusive_lock; static QemuCond exclusive_cond; static QemuCond exclusive_resume; -static int pending_cpus; +static bool exclusive_pending; +static int tcg_pending_threads; void qemu_init_cpu_loop(void) { @@ -142,7 +143,8 @@ void fork_end(int child) QTAILQ_REMOVE(&cpus, cpu, node); } } - pending_cpus = 0; + tcg_pending_threads = 0; + exclusive_pending = false; qemu_mutex_init(&exclusive_lock); qemu_mutex_init(&cpu_list_mutex); qemu_cond_init(&exclusive_cond); @@ -159,7 +161,7 @@ void fork_end(int child) must be held. */ static inline void exclusive_idle(void) { - while (pending_cpus) { + while (exclusive_pending) { qemu_cond_wait(&exclusive_resume, &exclusive_lock); } } @@ -173,15 +175,14 @@ static inline void start_exclusive(void) qemu_mutex_lock(&exclusive_lock); exclusive_idle(); - pending_cpus = 1; + exclusive_pending = true; /* Make all other cpus stop executing. */ CPU_FOREACH(other_cpu) { if (other_cpu->running) { - pending_cpus++; cpu_exit(other_cpu); } } - if (pending_cpus > 1) { + while (tcg_pending_threads) { qemu_cond_wait(&exclusive_cond, &exclusive_lock); } } @@ -189,7 +190,7 @@ static inline void start_exclusive(void) /* Finish an exclusive operation. */ static inline void __attribute__((unused)) end_exclusive(void) { - pending_cpus = 0; + exclusive_pending = false; qemu_cond_broadcast(&exclusive_resume); qemu_mutex_unlock(&exclusive_lock); } @@ -200,6 +201,7 @@ static inline void cpu_exec_start(CPUState *cpu) qemu_mutex_lock(&exclusive_lock); exclusive_idle(); cpu->running = true; + tcg_pending_threads++; qemu_mutex_unlock(&exclusive_lock); } @@ -208,11 +210,9 @@ static inline void cpu_exec_end(CPUState *cpu) { qemu_mutex_lock(&exclusive_lock); cpu->running = false; - if (pending_cpus > 1) { - pending_cpus--; - if (pending_cpus == 1) { - qemu_cond_signal(&exclusive_cond); - } + tcg_pending_threads--; + if (!tcg_pending_threads) { + qemu_cond_signal(&exclusive_cond); } exclusive_idle(); qemu_mutex_unlock(&exclusive_lock);