From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39821) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOozf-0006nh-9p for qemu-devel@nongnu.org; Mon, 10 Aug 2015 11:28:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZOoza-0008Cw-UB for qemu-devel@nongnu.org; Mon, 10 Aug 2015 11:28:07 -0400 Received: from greensocs.com ([193.104.36.180]:59260) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOoza-0008Co-JS for qemu-devel@nongnu.org; Mon, 10 Aug 2015 11:28:02 -0400 From: fred.konrad@greensocs.com Date: Mon, 10 Aug 2015 17:27:08 +0200 Message-Id: <1439220437-23957-11-git-send-email-fred.konrad@greensocs.com> In-Reply-To: <1439220437-23957-1-git-send-email-fred.konrad@greensocs.com> References: <1439220437-23957-1-git-send-email-fred.konrad@greensocs.com> Subject: [Qemu-devel] [RFC PATCH V7 10/19] cpu: remove exit_request global. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, mttcg@listserver.greensocs.com Cc: mark.burton@greensocs.com, a.rigo@virtualopensystems.com, guillaume.delbergue@greensocs.com, pbonzini@redhat.com, alex.bennee@linaro.org, fred.konrad@greensocs.com From: KONRAD Frederic This removes exit_request global and adds a variable in CPUState for this. Only the flag for the first cpu is used for the moment as we are still with one TCG thread. Signed-off-by: KONRAD Frederic --- cpu-exec.c | 15 --------------- cpus.c | 17 ++++++++++++++--- 2 files changed, 14 insertions(+), 18 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index a012e9d..21a7b96 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -363,8 +363,6 @@ static void cpu_handle_debug_exception(CPUState *cpu) /* main execution loop */ -volatile sig_atomic_t exit_request; - int cpu_exec(CPUState *cpu) { CPUClass *cc = CPU_GET_CLASS(cpu); @@ -402,20 +400,8 @@ int cpu_exec(CPUState *cpu) } current_cpu = cpu; - /* As long as current_cpu is null, up to the assignment just above, - * requests by other threads to exit the execution loop are expected to - * be issued using the exit_request global. We must make sure that our - * evaluation of the global value is performed past the current_cpu - * value transition point, which requires a memory barrier as well as - * an instruction scheduling constraint on modern architectures. */ - smp_mb(); - rcu_read_lock(); - if (unlikely(exit_request)) { - cpu->exit_request = 1; - } - cc->cpu_exec_enter(cpu); /* Calculate difference between guest clock and host clock. @@ -504,7 +490,6 @@ int cpu_exec(CPUState *cpu) } } if (unlikely(cpu->exit_request)) { - cpu->exit_request = 0; cpu->exception_index = EXCP_INTERRUPT; cpu_loop_exit(cpu); } diff --git a/cpus.c b/cpus.c index 154a081..2de9eae 100644 --- a/cpus.c +++ b/cpus.c @@ -139,6 +139,8 @@ typedef struct TimersState { } TimersState; static TimersState timers_state; +/* CPU associated to this thread. */ +static __thread CPUState *tcg_thread_cpu; int64_t cpu_get_icount_raw(void) { @@ -663,12 +665,18 @@ static void cpu_handle_guest_debug(CPUState *cpu) cpu->stopped = true; } +/** + * cpu_signal + * Signal handler when using TCG. + */ static void cpu_signal(int sig) { if (current_cpu) { cpu_exit(current_cpu); } - exit_request = 1; + + /* FIXME: We might want to check if the cpu is running? */ + tcg_thread_cpu->exit_request = true; } #ifdef CONFIG_LINUX @@ -1151,6 +1159,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) CPUState *cpu = arg; qemu_mutex_lock_iothread(); + tcg_thread_cpu = cpu; qemu_tcg_init_cpu_signals(); qemu_thread_get_self(cpu->thread); @@ -1480,7 +1489,8 @@ static void tcg_exec_all(void) if (next_cpu == NULL) { next_cpu = first_cpu; } - for (; next_cpu != NULL && !exit_request; next_cpu = CPU_NEXT(next_cpu)) { + for (; next_cpu != NULL && !first_cpu->exit_request; + next_cpu = CPU_NEXT(next_cpu)) { CPUState *cpu = next_cpu; qemu_clock_enable(QEMU_CLOCK_VIRTUAL, @@ -1496,7 +1506,8 @@ static void tcg_exec_all(void) break; } } - exit_request = 0; + + first_cpu->exit_request = 0; } void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg) -- 1.9.0