From patchwork Fri Jan 27 10:34:47 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Alex_Benn=C3=A9e?= X-Patchwork-Id: 92593 Delivered-To: patch@linaro.org Received: by 10.182.3.34 with SMTP id 2csp141451obz; Fri, 27 Jan 2017 02:47:05 -0800 (PST) X-Received: by 10.55.155.88 with SMTP id d85mr7398754qke.90.1485514025807; Fri, 27 Jan 2017 02:47:05 -0800 (PST) Return-Path: Received: from lists.gnu.org (lists.gnu.org. [2001:4830:134:3::11]) by mx.google.com with ESMTPS id t25si3259063qkt.36.2017.01.27.02.47.05 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 27 Jan 2017 02:47:05 -0800 (PST) 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 sp=NONE dis=NONE) header.from=linaro.org Received: from localhost ([::1]:44268 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cX43b-00018E-5X for patch@linaro.org; Fri, 27 Jan 2017 05:47:03 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47937) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cX3sE-0007qT-IT for qemu-devel@nongnu.org; Fri, 27 Jan 2017 05:35:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cX3sD-0002BW-Db for qemu-devel@nongnu.org; Fri, 27 Jan 2017 05:35:18 -0500 Received: from mail-wm0-x22b.google.com ([2a00:1450:400c:c09::22b]:37258) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cX3sD-0002Ar-56 for qemu-devel@nongnu.org; Fri, 27 Jan 2017 05:35:17 -0500 Received: by mail-wm0-x22b.google.com with SMTP id c206so129999731wme.0 for ; Fri, 27 Jan 2017 02:35:17 -0800 (PST) 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=6ke/+PrlBWT7mDFDKNOItj6FUDXHPfUdOHagOiF1agk=; b=SNWWOoseZcPtXTdgQHppk6Bi23yf3qkGpZQuFG3Cw0MkxBnjTM+cHLYeSF5Fpwk/pS hXq+kijYt0335BcRUXsvWMYy5boLPP7WNMxVzsDicp3fNTDo+5nsBWfvvwbN7/61ScaL LT7Wk0QsasUuz/V9Wt/P5esT1O4wddwx5L5Fs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=6ke/+PrlBWT7mDFDKNOItj6FUDXHPfUdOHagOiF1agk=; b=g+b8xgOfH816uDGU7+cvM++KanWs8DU7B3nZNT/OPgFC07sHv3jMc6GEBWx5q+5dGv jYoWjCrDd3x6P82KUCSuceCRx6VVgyi980PFNlleOMnjlx8z5RL2F1Xeedz16Co+OF49 pY1kAWAJ3wbtsecDKbsW4FbY356QVu1nG1RPQ5bID4/Kcd8ZbEhul3h7b7Y3HFmgHa9/ 717lHDoTgZTaTM/CF5uHSU9wYdt+1tnUcuFDF+V9s5R8NVuoFQtx4sEZpP9k95Vl8ARr 5HB3fGXWwhJT/5VZ9lq/vpu+vQsjsnf5koqL9Doq2hqwIWRvvQ9NmWUPw7WeUvuOeu3t S5ZA== X-Gm-Message-State: AIkVDXIfKJXgSFoAevmH0p6iONUBCQhHTFR6VYjjNUeBvZw4MB/atExTyCLNjoMwTxdqqLzy X-Received: by 10.28.58.204 with SMTP id h195mr2443413wma.116.1485513316003; Fri, 27 Jan 2017 02:35:16 -0800 (PST) Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id 186sm3075202wmw.24.2017.01.27.02.35.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 27 Jan 2017 02:35:11 -0800 (PST) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id 0F4E63E374A; Fri, 27 Jan 2017 10:35:06 +0000 (GMT) From: =?utf-8?q?Alex_Benn=C3=A9e?= To: Date: Fri, 27 Jan 2017 10:34:47 +0000 Message-Id: <20170127103505.18606-8-alex.bennee@linaro.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170127103505.18606-1-alex.bennee@linaro.org> References: <20170127103505.18606-1-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::22b Subject: [Qemu-devel] [PATCH v8 07/25] 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: Paolo Bonzini , Richard Henderson , =?utf-8?q?Alex_Benn=C3=A9e?= , "open list:Overall" , Peter Crosthwaite 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(-) -- 2.11.0 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