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[2001:4830:134:3::11]) by mx.google.com with ESMTPS id o22si2954607yba.99.2016.10.27.08.49.33 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 27 Oct 2016 08:49:34 -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]:42413 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bzmvt-0002JJ-FW for patch@linaro.org; Thu, 27 Oct 2016 11:49:33 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42655) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bzmKs-0004lR-G4 for qemu-devel@nongnu.org; Thu, 27 Oct 2016 11:11:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bzmKm-0007hM-3a for qemu-devel@nongnu.org; Thu, 27 Oct 2016 11:11:18 -0400 Received: from mail-wm0-x22e.google.com ([2a00:1450:400c:c09::22e]:36055) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1bzmKl-0007ga-Pe for qemu-devel@nongnu.org; Thu, 27 Oct 2016 11:11:12 -0400 Received: by mail-wm0-x22e.google.com with SMTP id b80so40032087wme.1 for ; Thu, 27 Oct 2016 08:11:11 -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=BZCqV8LFn3w+QrA8oTthppjT2+vAUoYeboIPVnaXZmE=; b=bDCXNU+QwhVaEv5bEMO0lfSvJH5G57fv0LeuSl/+kHQjKidPxuiSPvGiiWxxqvycvc Xh5jX3OinvusmmH/Uguj40fsCknq2Nr9tU0Lphpajtke/LQRJtUtBWcl92gjI4zV6ZAJ +QCHaDFELdBo0uIiYCwF+bxzhC/Wo9ENKD7kw= 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=BZCqV8LFn3w+QrA8oTthppjT2+vAUoYeboIPVnaXZmE=; b=cic+02Dd6erGYlLwc0p09+7wbTqt2EYKvvqGIKlJpY64SK319XblX2y6+z+jHWKKCf v0aRbo2KpB0/RiKZb5UXc7g0MeV/tGCQOU5nVFLXGOHflJV96hQIyqPEmsyL6wQ2h5JB ZTZdAYlvn7hSDepWBNPNam1jDa2sO4ZIhTVoCM9JkdDKJvk/SzoGelq2zqFzyp+SUY4P hRfejCSEi7hho7xzBj6Pio0OOoIMzEWSWsbyH/jM9Ay9dDGDytqqlYwgNuJl20CVAcXD aitugW+TqZR2YqR5WB0j9yBanmjyoN+/vebseMM0byG4nIjmdwvm5BkxhyglLhTN5uA5 Xssg== X-Gm-Message-State: ABUngvcyxugXjW1zQGsPDy0oqB24x7aoDyP7XzQdAurSkMQmtJu3AHNvJEEoQMiU4Kx30+WI X-Received: by 10.194.109.225 with SMTP id hv1mr2772758wjb.179.1477581070575; Thu, 27 Oct 2016 08:11:10 -0700 (PDT) Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id n72sm3770118wmd.11.2016.10.27.08.11.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Oct 2016 08:11:04 -0700 (PDT) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id 3B9F03E035C; Thu, 27 Oct 2016 16:11:00 +0100 (BST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: pbonzini@redhat.com Date: Thu, 27 Oct 2016 16:10:12 +0100 Message-Id: <20161027151030.20863-16-alex.bennee@linaro.org> X-Mailer: git-send-email 2.10.1 In-Reply-To: <20161027151030.20863-1-alex.bennee@linaro.org> References: <20161027151030.20863-1-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::22e Subject: [Qemu-devel] [PATCH v5 15/33] 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: mttcg@listserver.greensocs.com, peter.maydell@linaro.org, claudio.fontana@huawei.com, nikunj@linux.vnet.ibm.com, Peter Crosthwaite , jan.kiszka@siemens.com, mark.burton@greensocs.com, a.rigo@virtualopensystems.com, qemu-devel@nongnu.org, cota@braap.org, serge.fdrv@gmail.com, bobby.prani@gmail.com, rth@twiddle.net, =?UTF-8?q?Alex=20Benn=C3=A9e?= , fred.konrad@greensocs.com 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 Reviewed-by: Richard Henderson --- 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(-) -- 2.10.1 diff --git a/cpu-exec-common.c b/cpu-exec-common.c index 767d9c6..e2bc053 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 e9b50a6..6ea5507 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 ad4ab68..c6ff79f 100644 --- a/cpus.c +++ b/cpus.c @@ -747,8 +747,7 @@ 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) @@ -757,10 +756,23 @@ 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) @@ -779,7 +791,6 @@ static void stop_tcg_kick_timer(void) } } - /***********************************************************/ void hw_error(const char *fmt, ...) { @@ -1278,6 +1289,7 @@ 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); @@ -1297,6 +1309,8 @@ 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); @@ -1334,24 +1348,13 @@ 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); } @@ -1392,7 +1395,7 @@ 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 189deb8..b8b9989 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -407,7 +407,6 @@ 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