| Message ID | 20170127103922.19658-8-alex.bennee@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Remaining MTTCG Base patches and ARM enablement | expand |
Alex Bennée writes: > ..and make the definition local to cpus. In preparation for MTTCG the > concept of a global tcg_current_cpu will no longer make sense. However > we still need to keep track of it in the single-threaded case to be able > to exit quickly when required. > > qemu_cpu_kick_no_halt() moves and becomes qemu_cpu_kick_rr_cpu() to > emphasise its use-case. qemu_cpu_kick now kicks the relevant cpu as > well as qemu_kick_rr_cpu() which will become a no-op in MTTCG. > > For the time being the setting of the global exit_request remains. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > Reviewed-by: Richard Henderson <rth@twiddle.net> > --- > v4: > - keep global exit_request setting for now > - fix merge conflicts > v5: > - merge conflicts with kick changes > --- > cpu-exec-common.c | 1 - > cpu-exec.c | 3 --- > cpus.c | 41 ++++++++++++++++++++++------------------- > include/exec/exec-all.h | 1 - > 4 files changed, 22 insertions(+), 24 deletions(-) > > diff --git a/cpu-exec-common.c b/cpu-exec-common.c > index 767d9c6f0c..e2bc053372 100644 > --- a/cpu-exec-common.c > +++ b/cpu-exec-common.c > @@ -24,7 +24,6 @@ > #include "exec/memory-internal.h" > > bool exit_request; > -CPUState *tcg_current_cpu; > > /* exit the current TB, but without causing any exception to be raised */ > void cpu_loop_exit_noexc(CPUState *cpu) > diff --git a/cpu-exec.c b/cpu-exec.c > index 1b8685dc21..f9e836c8dd 100644 > --- a/cpu-exec.c > +++ b/cpu-exec.c > @@ -609,7 +609,6 @@ int cpu_exec(CPUState *cpu) > return EXCP_HALTED; > } > > - atomic_mb_set(&tcg_current_cpu, cpu); > rcu_read_lock(); > > if (unlikely(atomic_mb_read(&exit_request))) { > @@ -668,7 +667,5 @@ int cpu_exec(CPUState *cpu) > /* fail safe : never use current_cpu outside cpu_exec() */ > current_cpu = NULL; > > - /* Does not need atomic_mb_set because a spurious wakeup is okay. */ > - atomic_set(&tcg_current_cpu, NULL); > return ret; > } > diff --git a/cpus.c b/cpus.c > index a98925105c..6d64199831 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -779,8 +779,7 @@ void configure_icount(QemuOpts *opts, Error **errp) > */ > > static QEMUTimer *tcg_kick_vcpu_timer; > - > -static void qemu_cpu_kick_no_halt(void); > +static CPUState *tcg_current_rr_cpu; > > #define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10) > > @@ -789,10 +788,23 @@ static inline int64_t qemu_tcg_next_kick(void) > return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + TCG_KICK_PERIOD; > } > > +/* Kick the currently round-robin scheduled vCPU */ > +static void qemu_cpu_kick_rr_cpu(void) > +{ > + CPUState *cpu; > + atomic_mb_set(&exit_request, 1); > + do { > + cpu = atomic_mb_read(&tcg_current_rr_cpu); > + if (cpu) { > + cpu_exit(cpu); > + } > + } while (cpu != atomic_mb_read(&tcg_current_rr_cpu)); > +} > + > static void kick_tcg_thread(void *opaque) > { > timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick()); > - qemu_cpu_kick_no_halt(); > + qemu_cpu_kick_rr_cpu(); > } > > static void start_tcg_kick_timer(void) > @@ -812,7 +824,6 @@ static void stop_tcg_kick_timer(void) > } > } > > - > /***********************************************************/ > void hw_error(const char *fmt, ...) > { > @@ -1323,6 +1334,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) > } > > for (; cpu != NULL && !exit_request; cpu = CPU_NEXT(cpu)) { > + atomic_mb_set(&tcg_current_rr_cpu, cpu); > > qemu_clock_enable(QEMU_CLOCK_VIRTUAL, > (cpu->singlestep_enabled & SSTEP_NOTIMER) == 0); > @@ -1342,6 +1354,8 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) > } > > } /* for cpu.. */ > + /* Does not need atomic_mb_set because a spurious wakeup is okay. */ > + atomic_set(&tcg_current_rr_cpu, NULL); > > /* Pairs with smp_wmb in qemu_cpu_kick. */ > atomic_mb_set(&exit_request, 0); > @@ -1420,24 +1434,13 @@ static void qemu_cpu_kick_thread(CPUState *cpu) > #endif > } > > -static void qemu_cpu_kick_no_halt(void) > -{ > - CPUState *cpu; > - /* Ensure whatever caused the exit has reached the CPU threads before > - * writing exit_request. > - */ > - atomic_mb_set(&exit_request, 1); > - cpu = atomic_mb_read(&tcg_current_cpu); > - if (cpu) { > - cpu_exit(cpu); > - } > -} > - > void qemu_cpu_kick(CPUState *cpu) > { > qemu_cond_broadcast(cpu->halt_cond); > if (tcg_enabled()) { > - qemu_cpu_kick_no_halt(); > + cpu_exit(cpu); > + /* Also ensure current RR cpu is kicked */ > + qemu_cpu_kick_rr_cpu(); > } else { > if (hax_enabled()) { > /* > @@ -1485,7 +1488,7 @@ void qemu_mutex_lock_iothread(void) > atomic_dec(&iothread_requesting_mutex); > } else { > if (qemu_mutex_trylock(&qemu_global_mutex)) { > - qemu_cpu_kick_no_halt(); > + qemu_cpu_kick_rr_cpu(); > qemu_mutex_lock(&qemu_global_mutex); > } > atomic_dec(&iothread_requesting_mutex); > diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h > index bbc9478a50..3cbd359dd7 100644 > --- a/include/exec/exec-all.h > +++ b/include/exec/exec-all.h > @@ -404,7 +404,6 @@ bool memory_region_is_unassigned(MemoryRegion *mr); > extern int singlestep; > > /* cpu-exec.c, accessed with atomic_mb_read/atomic_mb_set */ > -extern CPUState *tcg_current_cpu; > extern bool exit_request; > > #endif Reviewed-by: Pranith Kumar <bobby.prani@gmail.com> -- Pranith
diff --git a/cpu-exec-common.c b/cpu-exec-common.c index 767d9c6f0c..e2bc053372 100644 --- a/cpu-exec-common.c +++ b/cpu-exec-common.c @@ -24,7 +24,6 @@ #include "exec/memory-internal.h" bool exit_request; -CPUState *tcg_current_cpu; /* exit the current TB, but without causing any exception to be raised */ void cpu_loop_exit_noexc(CPUState *cpu) diff --git a/cpu-exec.c b/cpu-exec.c index 1b8685dc21..f9e836c8dd 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -609,7 +609,6 @@ int cpu_exec(CPUState *cpu) return EXCP_HALTED; } - atomic_mb_set(&tcg_current_cpu, cpu); rcu_read_lock(); if (unlikely(atomic_mb_read(&exit_request))) { @@ -668,7 +667,5 @@ int cpu_exec(CPUState *cpu) /* fail safe : never use current_cpu outside cpu_exec() */ current_cpu = NULL; - /* Does not need atomic_mb_set because a spurious wakeup is okay. */ - atomic_set(&tcg_current_cpu, NULL); return ret; } diff --git a/cpus.c b/cpus.c index a98925105c..6d64199831 100644 --- a/cpus.c +++ b/cpus.c @@ -779,8 +779,7 @@ void configure_icount(QemuOpts *opts, Error **errp) */ static QEMUTimer *tcg_kick_vcpu_timer; - -static void qemu_cpu_kick_no_halt(void); +static CPUState *tcg_current_rr_cpu; #define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10) @@ -789,10 +788,23 @@ static inline int64_t qemu_tcg_next_kick(void) return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + TCG_KICK_PERIOD; } +/* Kick the currently round-robin scheduled vCPU */ +static void qemu_cpu_kick_rr_cpu(void) +{ + CPUState *cpu; + atomic_mb_set(&exit_request, 1); + do { + cpu = atomic_mb_read(&tcg_current_rr_cpu); + if (cpu) { + cpu_exit(cpu); + } + } while (cpu != atomic_mb_read(&tcg_current_rr_cpu)); +} + static void kick_tcg_thread(void *opaque) { timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick()); - qemu_cpu_kick_no_halt(); + qemu_cpu_kick_rr_cpu(); } static void start_tcg_kick_timer(void) @@ -812,7 +824,6 @@ static void stop_tcg_kick_timer(void) } } - /***********************************************************/ void hw_error(const char *fmt, ...) { @@ -1323,6 +1334,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) } for (; cpu != NULL && !exit_request; cpu = CPU_NEXT(cpu)) { + atomic_mb_set(&tcg_current_rr_cpu, cpu); qemu_clock_enable(QEMU_CLOCK_VIRTUAL, (cpu->singlestep_enabled & SSTEP_NOTIMER) == 0); @@ -1342,6 +1354,8 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) } } /* for cpu.. */ + /* Does not need atomic_mb_set because a spurious wakeup is okay. */ + atomic_set(&tcg_current_rr_cpu, NULL); /* Pairs with smp_wmb in qemu_cpu_kick. */ atomic_mb_set(&exit_request, 0); @@ -1420,24 +1434,13 @@ static void qemu_cpu_kick_thread(CPUState *cpu) #endif } -static void qemu_cpu_kick_no_halt(void) -{ - CPUState *cpu; - /* Ensure whatever caused the exit has reached the CPU threads before - * writing exit_request. - */ - atomic_mb_set(&exit_request, 1); - cpu = atomic_mb_read(&tcg_current_cpu); - if (cpu) { - cpu_exit(cpu); - } -} - void qemu_cpu_kick(CPUState *cpu) { qemu_cond_broadcast(cpu->halt_cond); if (tcg_enabled()) { - qemu_cpu_kick_no_halt(); + cpu_exit(cpu); + /* Also ensure current RR cpu is kicked */ + qemu_cpu_kick_rr_cpu(); } else { if (hax_enabled()) { /* @@ -1485,7 +1488,7 @@ void qemu_mutex_lock_iothread(void) atomic_dec(&iothread_requesting_mutex); } else { if (qemu_mutex_trylock(&qemu_global_mutex)) { - qemu_cpu_kick_no_halt(); + qemu_cpu_kick_rr_cpu(); qemu_mutex_lock(&qemu_global_mutex); } atomic_dec(&iothread_requesting_mutex); diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index bbc9478a50..3cbd359dd7 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -404,7 +404,6 @@ bool memory_region_is_unassigned(MemoryRegion *mr); extern int singlestep; /* cpu-exec.c, accessed with atomic_mb_read/atomic_mb_set */ -extern CPUState *tcg_current_cpu; extern bool exit_request; #endif