throttle: add throttle_detach/attach_aio_context()

Block I/O throttling uses timers and currently always adds them to the
main loop.  Throttling will break if bdrv_set_aio_context() is used to
move a BlockDriverState to a different AioContext.

This patch adds throttle_detach/attach_aio_context() interfaces so the
throttling timers and uses them to move timers to the new AioContext.
Note that bdrv_set_aio_context() already drains all requests so we're
sure no throttled requests are pending.

The test cases need to be updated since the throttle_init() interface
has changed.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>

1 files changed, 20 insertions, 5 deletions

diff --git a/tests/test-throttle.c b/tests/test-throttle.c
index 1d4ffd3603..5fa5000124 100644
--- a/tests/test-throttle.c
+++ b/tests/test-throttle.c
@@ -12,8 +12,10 @@
 
 #include <glib.h>
 #include <math.h>
+#include "block/aio.h"
 #include "qemu/throttle.h"
 
+AioContext     *ctx;
 LeakyBucket    bkt;
 ThrottleConfig cfg;
 ThrottleState  ts;
@@ -104,7 +106,8 @@ static void test_init(void)
     memset(&ts, 1, sizeof(ts));
 
     /* init the structure */
-    throttle_init(&ts, QEMU_CLOCK_VIRTUAL, read_timer_cb, write_timer_cb, &ts);
+    throttle_init(&ts, ctx, QEMU_CLOCK_VIRTUAL,
+                  read_timer_cb, write_timer_cb, &ts);
 
     /* check initialized fields */
     g_assert(ts.clock_type == QEMU_CLOCK_VIRTUAL);
@@ -126,7 +129,8 @@ static void test_init(void)
 static void test_destroy(void)
 {
     int i;
-    throttle_init(&ts, QEMU_CLOCK_VIRTUAL, read_timer_cb, write_timer_cb, &ts);
+    throttle_init(&ts, ctx, QEMU_CLOCK_VIRTUAL,
+                  read_timer_cb, write_timer_cb, &ts);
     throttle_destroy(&ts);
     for (i = 0; i < 2; i++) {
         g_assert(!ts.timers[i]);
@@ -165,7 +169,8 @@ static void test_config_functions(void)
 
     orig_cfg.op_size = 1;
 
-    throttle_init(&ts, QEMU_CLOCK_VIRTUAL, read_timer_cb, write_timer_cb, &ts);
+    throttle_init(&ts, ctx, QEMU_CLOCK_VIRTUAL,
+                  read_timer_cb, write_timer_cb, &ts);
     /* structure reset by throttle_init previous_leak should be null */
     g_assert(!ts.previous_leak);
     throttle_config(&ts, &orig_cfg);
@@ -324,7 +329,8 @@ static void test_have_timer(void)
     g_assert(!throttle_have_timer(&ts));
 
     /* init the structure */
-    throttle_init(&ts, QEMU_CLOCK_VIRTUAL, read_timer_cb, write_timer_cb, &ts);
+    throttle_init(&ts, ctx, QEMU_CLOCK_VIRTUAL,
+                  read_timer_cb, write_timer_cb, &ts);
 
     /* timer set by init should return true */
     g_assert(throttle_have_timer(&ts));
@@ -357,7 +363,8 @@ static bool do_test_accounting(bool is_ops, /* are we testing bps or ops */
 
     cfg.op_size = op_size;
 
-    throttle_init(&ts, QEMU_CLOCK_VIRTUAL, read_timer_cb, write_timer_cb, &ts);
+    throttle_init(&ts, ctx, QEMU_CLOCK_VIRTUAL,
+                  read_timer_cb, write_timer_cb, &ts);
     throttle_config(&ts, &cfg);
 
     /* account a read */
@@ -461,7 +468,15 @@ static void test_accounting(void)
 
 int main(int argc, char **argv)
 {
+    GSource *src;
+
     init_clocks();
+
+    ctx = aio_context_new();
+    src = aio_get_g_source(ctx);
+    g_source_attach(src, NULL);
+    g_source_unref(src);
+
     do {} while (g_main_context_iteration(NULL, false));
 
     /* tests in the same order as the header function declarations */