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[Qemu-devel] [PATCH v2 04/13] exec: do not use qemu/tls.h
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH v2 04/13] exec: do not use qemu/tls.h |
Date: |
Mon, 15 Jul 2013 22:42:53 +0800 |
From: Paolo Bonzini <address@hidden>
The next patch will change qemu/tls.h to support more platforms, but at
some performance cost. Declare current_cpu directly instead of using
the tls.h abstractions.
Signed-off-by: Paolo Bonzini <address@hidden>
---
Paolo may have further improvements for these patches. This is my local
version.
exec.c | 10 ++++++++--
include/qemu/tls.h | 52 ----------------------------------------------------
include/qom/cpu.h | 14 +++++++++++---
3 files changed, 19 insertions(+), 57 deletions(-)
delete mode 100644 include/qemu/tls.h
diff --git a/exec.c b/exec.c
index 80ee2ab..b8db730 100644
--- a/exec.c
+++ b/exec.c
@@ -70,9 +70,15 @@ static MemoryRegion io_mem_unassigned;
#endif
CPUState *first_cpu;
+
/* current CPU in the current thread. It is only valid inside
- cpu_exec() */
-DEFINE_TLS(CPUState *, current_cpu);
+ * cpu_exec(). See comment in include/exec/cpu-all.h. */
+#if defined CONFIG_KVM || (defined CONFIG_USER_ONLY && defined CONFIG_USE_NPTL)
+__thread CPUState *current_cpu;
+#else
+CPUState *current_cpu;
+#endif
+
/* 0 = Do not count executed instructions.
1 = Precise instruction counting.
2 = Adaptive rate instruction counting. */
diff --git a/include/qemu/tls.h b/include/qemu/tls.h
deleted file mode 100644
index b92ea9d..0000000
--- a/include/qemu/tls.h
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Abstraction layer for defining and using TLS variables
- *
- * Copyright (c) 2011 Red Hat, Inc
- * Copyright (c) 2011 Linaro Limited
- *
- * Authors:
- * Paolo Bonzini <address@hidden>
- * Peter Maydell <address@hidden>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef QEMU_TLS_H
-#define QEMU_TLS_H
-
-/* Per-thread variables. Note that we only have implementations
- * which are really thread-local on Linux; the dummy implementations
- * define plain global variables.
- *
- * This means that for the moment use should be restricted to
- * per-VCPU variables, which are OK because:
- * - the only -user mode supporting multiple VCPU threads is linux-user
- * - TCG system mode is single-threaded regarding VCPUs
- * - KVM system mode is multi-threaded but limited to Linux
- *
- * TODO: proper implementations via Win32 .tls sections and
- * POSIX pthread_getspecific.
- */
-#ifdef __linux__
-#define DECLARE_TLS(type, x) extern DEFINE_TLS(type, x)
-#define DEFINE_TLS(type, x) __thread __typeof__(type) tls__##x
-#define tls_var(x) tls__##x
-#else
-/* Dummy implementations which define plain global variables */
-#define DECLARE_TLS(type, x) extern DEFINE_TLS(type, x)
-#define DEFINE_TLS(type, x) __typeof__(type) tls__##x
-#define tls_var(x) tls__##x
-#endif
-
-#endif
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 147c256..cb26e1a 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -24,7 +24,6 @@
#include "hw/qdev-core.h"
#include "exec/hwaddr.h"
#include "qemu/thread.h"
-#include "qemu/tls.h"
#include "qemu/typedefs.h"
typedef int (*WriteCoreDumpFunction)(void *buf, size_t size, void *opaque);
@@ -163,8 +162,17 @@ struct CPUState {
extern CPUState *first_cpu;
-DECLARE_TLS(CPUState *, current_cpu);
-#define current_cpu tls_var(current_cpu)
+/* This is thread-local depending on __linux__ because:
+ * - the only -user mode supporting multiple VCPU threads is linux-user
+ * - TCG system mode is single-threaded regarding VCPUs
+ * - KVM system mode is multi-threaded but limited to Linux
+ */
+#if defined CONFIG_KVM || (defined CONFIG_USER_ONLY && defined CONFIG_USE_NPTL)
+extern __thread CPUState *current_cpu;
+#else
+extern CPUState *current_cpu;
+#endif
+
/**
* cpu_paging_enabled:
--
1.8.1.4
- [Qemu-devel] [PATCH v2 00/13] dataplane: use block layer, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 01/13] dataplane: sync virtio.c and vring.c virtqueue state, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 02/13] block: add BlockDevOps->drain_threads_cb(), Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 03/13] virtio-blk: implement BlockDevOps->drain_threads_cb(), Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 04/13] exec: do not use qemu/tls.h,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH v2 05/13] qemu-thread: add TLS wrappers, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 06/13] block: add thread_aio_context TLS variable, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 07/13] block: drop bdrv_get_aio_context(), Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 09/13] linux-aio: bind EventNotifier to current AioContext, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 08/13] main-loop: use thread-local AioContext, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 10/13] block: disable I/O throttling outside main loop, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 11/13] dataplane: use block layer for I/O, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 12/13] dataplane: drop ioq Linux AIO request queue, Stefan Hajnoczi, 2013/07/15
- [Qemu-devel] [PATCH v2 13/13] block: drop raw_get_aio_fd(), Stefan Hajnoczi, 2013/07/15
- Re: [Qemu-devel] [PATCH v2 00/13] dataplane: use block layer, Paolo Bonzini, 2013/07/15