[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [RFC 07/13] block: add thread_aio_context TLS variable
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [RFC 07/13] block: add thread_aio_context TLS variable |
Date: |
Fri, 14 Jun 2013 11:48:27 +0200 |
BH and fd handler APIs need to know which AioContext (event loop) to run
inside. Passing it around everywhere is not feasible since it would
require adding arguments to any call-chain that invokes BH and fd
handler APIs (hint: there are many and they change).
Instead make the AioContext pointer thread-local. This way, any
function that needs to use an AioContext can find it. In particular:
the iothread and vcpu threads share the main AioContext since they hold
the global mutex while running. Dataplane threads will use their own
AioContexts.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
async.c | 2 ++
cpus.c | 2 ++
include/block/aio.h | 4 ++++
main-loop.c | 1 +
4 files changed, 9 insertions(+)
diff --git a/async.c b/async.c
index 90fe906..765cbc0 100644
--- a/async.c
+++ b/async.c
@@ -27,6 +27,8 @@
#include "block/thread-pool.h"
#include "qemu/main-loop.h"
+DEFINE_TLS(AioContext*, thread_aio_context);
+
/***********************************************************/
/* bottom halves (can be seen as timers which expire ASAP) */
diff --git a/cpus.c b/cpus.c
index c232265..529d612 100644
--- a/cpus.c
+++ b/cpus.c
@@ -741,6 +741,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg)
qemu_thread_get_self(cpu->thread);
cpu->thread_id = qemu_get_thread_id();
cpu_single_env = env;
+ *alloc_thread_aio_context() = qemu_get_aio_context();
r = kvm_init_vcpu(cpu);
if (r < 0) {
@@ -815,6 +816,7 @@ static void tcg_exec_all(void);
static void tcg_signal_cpu_creation(CPUState *cpu, void *data)
{
cpu->thread_id = qemu_get_thread_id();
+ *alloc_thread_aio_context() = qemu_get_aio_context();
cpu->created = true;
}
diff --git a/include/block/aio.h b/include/block/aio.h
index 1836793..6ee9369 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -17,6 +17,7 @@
#include "qemu-common.h"
#include "qemu/queue.h"
#include "qemu/event_notifier.h"
+#include "qemu/tls.h"
typedef struct BlockDriverAIOCB BlockDriverAIOCB;
typedef void BlockDriverCompletionFunc(void *opaque, int ret);
@@ -74,6 +75,9 @@ typedef struct AioContext {
/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
typedef int (AioFlushEventNotifierHandler)(EventNotifier *e);
+/* Each thread can have a default AioContext */
+DECLARE_TLS(AioContext*, thread_aio_context);
+
/**
* aio_context_new: Allocate a new AioContext.
*
diff --git a/main-loop.c b/main-loop.c
index cf36645..51eeb0f 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -142,6 +142,7 @@ int qemu_init_main_loop(void)
gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
qemu_aio_context = aio_context_new();
+ *get_thread_aio_context() = qemu_aio_context;
src = aio_get_g_source(qemu_aio_context);
g_source_attach(src, NULL);
g_source_unref(src);
--
1.8.1.4
- [Qemu-devel] [RFC 00/13] dataplane: use block layer, Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 01/13] block: fix bdrv_flush() ordering in bdrv_close(), Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 02/13] dataplane: sync virtio.c and vring.c virtqueue state, Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 03/13] block: add BlockDevOps->drain_threads_cb(), Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 04/13] virtio-blk: implement BlockDevOps->drain_threads_cb(), Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 06/13] qemu-thread: add TLS wrappers, Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 07/13] block: add thread_aio_context TLS variable,
Stefan Hajnoczi <=
- [Qemu-devel] [RFC 09/13] main-loop: use thread-local AioContext, Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 10/13] block: disable I/O throttling outside main loop, Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 08/13] block: drop bdrv_get_aio_context(), Stefan Hajnoczi, 2013/06/14
[Qemu-devel] [RFC 12/13] dataplane: drop ioq Linux AIO request queue, Stefan Hajnoczi, 2013/06/14
[Qemu-devel] [RFC 11/13] dataplane: use block layer for I/O, Stefan Hajnoczi, 2013/06/14
[Qemu-devel] [RFC 13/13] block: drop raw_get_aio_fd(), Stefan Hajnoczi, 2013/06/14