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[2001:4830:134:3::11]) by mx.google.com with ESMTPS id y15si1861870qtc.59.2016.08.11.08.31.25 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 11 Aug 2016 08:31:25 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) client-ip=2001:4830:134:3::11; Authentication-Results: mx.google.com; dkim=fail header.i=@linaro.org; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) smtp.mailfrom=qemu-devel-bounces+patch=linaro.org@nongnu.org; dmarc=fail (p=NONE dis=NONE) header.from=linaro.org Received: from localhost ([::1]:49172 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXrx7-0001Xl-Ag for patch@linaro.org; Thu, 11 Aug 2016 11:31:25 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57379) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXrqV-0003eC-6q for qemu-devel@nongnu.org; Thu, 11 Aug 2016 11:24:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bXrqS-0006ac-TF for qemu-devel@nongnu.org; Thu, 11 Aug 2016 11:24:35 -0400 Received: from mail-wm0-x232.google.com ([2a00:1450:400c:c09::232]:37273) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXrqS-0006a7-70 for qemu-devel@nongnu.org; Thu, 11 Aug 2016 11:24:32 -0400 Received: by mail-wm0-x232.google.com with SMTP id i5so3239728wmg.0 for ; Thu, 11 Aug 2016 08:24:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=1WWZIMk6T09eW93MOhXF66/qLlIxPYCStRnCvbJBlxc=; b=X5IyaBNqwgdBheoZd8VRg/09RFxIQIw9vHjyo9jyBltpoYq13gBOkuh5PhKaj0NK34 ZLZixQ/R6qWsaD4ykuJvXVayrxfcxe/JWDqIM7h974yD+Bt2inomk+f3TA8K/ch2qTuZ TWHFLNjArt5Wr5uTonEkgkMGBdCNM3ExeANrU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=1WWZIMk6T09eW93MOhXF66/qLlIxPYCStRnCvbJBlxc=; b=QbEkuAcc8pveS5r9DCK5uc7yzw0KLQVXfE9dbnVb8Bk6iK1siRAq7LfX/VK7y/udEh tn6zRbQKWtDVeL5N7Y8u5tE1P4DvwlUFLT2SB0bYuXWOjivHJF91Fc+2eDHz8AgmuPjw 2kxWGoBF72FqrOlbl1erC3Fn9O9d5yER1kF2tzxQzFUtfPi8t1/qx0JxJ2JBAFAZb3Gs 4xBFbyVD55trDfaR2KZL4l//5VD2pfe1Kr1axdGyDtt2mdgCHwVMsdm7WOzYedsQf0LV U6HDwTqvyCcZH1vtOFYgJjCDv7/pbCOOb26uBqKv0QsnkNv0UlgYrkTLwsYq8WPe2AS7 eRIQ== X-Gm-Message-State: AEkooutrqv9ZUkyQtTJrwvFjYTcJp1XvxQyr9mkxEG7HzWrTH6Dk4g4/KG8M4c8l5F36P8J7 X-Received: by 10.28.232.149 with SMTP id f21mr9231163wmi.51.1470929071509; Thu, 11 Aug 2016 08:24:31 -0700 (PDT) Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id d64sm275696wmc.22.2016.08.11.08.24.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Aug 2016 08:24:31 -0700 (PDT) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id F13853E0307; Thu, 11 Aug 2016 16:24:30 +0100 (BST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: mttcg@listserver.greensocs.com, qemu-devel@nongnu.org, fred.konrad@greensocs.com, a.rigo@virtualopensystems.com, cota@braap.org, bobby.prani@gmail.com, nikunj@linux.vnet.ibm.com Date: Thu, 11 Aug 2016 16:24:11 +0100 Message-Id: <1470929064-4092-16-git-send-email-alex.bennee@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1470929064-4092-1-git-send-email-alex.bennee@linaro.org> References: <1470929064-4092-1-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2a00:1450:400c:c09::232 Subject: [Qemu-devel] [RFC v4 15/28] tcg: rename tcg_current_cpu to tcg_current_rr_cpu X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, claudio.fontana@huawei.com, Peter Crosthwaite , jan.kiszka@siemens.com, mark.burton@greensocs.com, serge.fdrv@gmail.com, pbonzini@redhat.com, =?UTF-8?q?Alex=20Benn=C3=A9e?= , rth@twiddle.net Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" ..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 --- v4: - keep global exit_request setting for now - fix merge conflicts --- cpu-exec-common.c | 3 ++- cpu-exec.c | 3 --- cpus.c | 41 ++++++++++++++++++++++++----------------- include/exec/exec-all.h | 1 - 4 files changed, 26 insertions(+), 22 deletions(-) -- 2.7.4 diff --git a/cpu-exec-common.c b/cpu-exec-common.c index 0bec55a..e220ba7 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; int tcg_pending_threads; /* exit the current TB, but without causing any exception to be raised */ @@ -140,6 +139,7 @@ void run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data) struct qemu_work_item wi; bool done = false; + /* Always true when using tcg RR scheduling from a vCPU context */ if (qemu_cpu_is_self(cpu)) { func(cpu, data); return; @@ -163,6 +163,7 @@ void async_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data) { struct qemu_work_item wi; + /* Always true when using tcg RR scheduling from a vCPU context */ if (qemu_cpu_is_self(cpu)) { func(cpu, data); return; diff --git a/cpu-exec.c b/cpu-exec.c index 93a0eb1..42fbf7d 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -578,7 +578,6 @@ 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))) { @@ -637,7 +636,5 @@ 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 8c49d6c..732b21f 100644 --- a/cpus.c +++ b/cpus.c @@ -1193,7 +1193,6 @@ static void deal_with_unplugged_cpus(void) * This is done explicitly rather than relying on side-effects * elsewhere. */ -static void qemu_cpu_kick_no_halt(void); #define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10) @@ -1202,11 +1201,27 @@ static inline int64_t qemu_tcg_next_kick(void) return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + TCG_KICK_PERIOD; } +/* only used in single-thread tcg mode */ +static CPUState *tcg_current_rr_cpu; + +/* 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) { QEMUTimer *self = *(QEMUTimer **) opaque; timer_mod(self, qemu_tcg_next_kick()); - qemu_cpu_kick_no_halt(); + qemu_cpu_kick_rr_cpu(); } static void *qemu_tcg_cpu_thread_fn(void *arg) @@ -1257,6 +1272,7 @@ 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); @@ -1278,6 +1294,8 @@ 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); @@ -1315,24 +1333,13 @@ 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 { qemu_cpu_kick_thread(cpu); } @@ -1373,7 +1380,7 @@ 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 d73b0e6..3547dfa 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -408,7 +408,6 @@ 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 int tcg_pending_threads; extern bool exit_request;