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[Qemu-devel] [PATCH 14/42] migration: prepare to access s->state outside
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 14/42] migration: prepare to access s->state outside critical sections |
Date: |
Fri, 22 Feb 2013 17:36:20 +0100 |
Accessing s->state outside the big QEMU lock will simplify a bit the
locking/unlocking of the iothread lock.
We need to keep the lock in migrate_fd_error and migrate_fd_completed,
however, because they call migrate_fd_cleanup.
Reviewed-by: Orit Wasserman <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
migration.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/migration.c b/migration.c
index b091532..b40755f 100644
--- a/migration.c
+++ b/migration.c
@@ -279,19 +279,25 @@ static void migrate_fd_cleanup(MigrationState *s)
notifier_list_notify(&migration_state_notifiers, s);
}
+static void migrate_finish_set_state(MigrationState *s, int new_state)
+{
+ if (__sync_val_compare_and_swap(&s->state, MIG_STATE_ACTIVE,
+ new_state) == new_state) {
+ trace_migrate_set_state(new_state);
+ }
+}
+
void migrate_fd_error(MigrationState *s)
{
DPRINTF("setting error state\n");
- s->state = MIG_STATE_ERROR;
- trace_migrate_set_state(MIG_STATE_ERROR);
+ migrate_finish_set_state(s, MIG_STATE_ERROR);
migrate_fd_cleanup(s);
}
static void migrate_fd_completed(MigrationState *s)
{
DPRINTF("setting completed state\n");
- s->state = MIG_STATE_COMPLETED;
- trace_migrate_set_state(MIG_STATE_COMPLETED);
+ migrate_finish_set_state(s, MIG_STATE_COMPLETED);
migrate_fd_cleanup(s);
}
@@ -316,13 +322,9 @@ static ssize_t migrate_fd_put_buffer(MigrationState *s,
const void *data,
static void migrate_fd_cancel(MigrationState *s)
{
- if (s->state != MIG_STATE_ACTIVE)
- return;
-
DPRINTF("cancelling migration\n");
- s->state = MIG_STATE_CANCELLED;
- trace_migrate_set_state(MIG_STATE_CANCELLED);
+ migrate_finish_set_state(s, MIG_STATE_CANCELLED);
migrate_fd_cleanup(s);
}
@@ -657,12 +659,14 @@ static void *buffered_file_thread(void *opaque)
qemu_mutex_lock_iothread();
DPRINTF("beginning savevm\n");
qemu_savevm_state_begin(s->file, &s->params);
+ qemu_mutex_unlock_iothread();
while (s->state == MIG_STATE_ACTIVE) {
int64_t current_time;
uint64_t pending_size;
if (s->bytes_xfer < s->xfer_limit) {
+ qemu_mutex_lock_iothread();
DPRINTF("iterate\n");
pending_size = qemu_savevm_state_pending(s->file, max_size);
DPRINTF("pending size %lu max %lu\n", pending_size, max_size);
@@ -678,8 +682,9 @@ static void *buffered_file_thread(void *opaque)
qemu_savevm_state_complete(s->file);
last_round = true;
}
+ qemu_mutex_unlock_iothread();
}
- qemu_mutex_unlock_iothread();
+
current_time = qemu_get_clock_ms(rt_clock);
if (current_time >= initial_time + BUFFER_DELAY) {
uint64_t transferred_bytes = s->bytes_xfer;
@@ -706,14 +711,18 @@ static void *buffered_file_thread(void *opaque)
sleep_time += qemu_get_clock_ms(rt_clock) - current_time;
}
buffered_flush(s);
- qemu_mutex_lock_iothread();
if (qemu_file_get_error(s->file)) {
+ qemu_mutex_lock_iothread();
migrate_fd_error(s);
+ qemu_mutex_unlock_iothread();
} else if (last_round && s->buffer_size == 0) {
+ qemu_mutex_lock_iothread();
migrate_fd_completed(s);
+ qemu_mutex_unlock_iothread();
}
}
+ qemu_mutex_lock_iothread();
if (s->state == MIG_STATE_COMPLETED) {
int64_t end_time = qemu_get_clock_ms(rt_clock);
s->total_time = end_time - s->total_time;
@@ -725,8 +734,8 @@ static void *buffered_file_thread(void *opaque)
vm_start();
}
}
-
qemu_mutex_unlock_iothread();
+
g_free(s->buffer);
return NULL;
}
--
1.8.1.2
- [Qemu-devel] [PATCH 05/42] block-migration: remove useless calls to blk_mig_cleanup, (continued)
- [Qemu-devel] [PATCH 05/42] block-migration: remove useless calls to blk_mig_cleanup, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 02/42] migration: always use vm_stop_force_state, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 06/42] qemu-file: pass errno from qemu_fflush via f->last_error, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 08/42] qemu-file: temporarily expose qemu_file_set_error and qemu_fflush, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 03/42] migration: move more error handling to migrate_fd_cleanup, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 11/42] migration: simplify error handling, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 09/42] migration: flush all data to fd when buffered_flush is called, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 16/42] block-migration: remove variables that are never read, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 13/42] migration: add migrate_set_state tracepoint, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 12/42] migration: do not nest flushing of device data, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 14/42] migration: prepare to access s->state outside critical sections,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 18/42] block-migration: document usage of state across threads, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 20/42] migration: reorder SaveVMHandlers members, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 22/42] migration: run setup callbacks out of big lock, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 21/42] migration: run pending/iterate callbacks out of big lock, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 24/42] Rename buffered_ to migration_, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 23/42] migration: yay, buffering is gone, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 25/42] qemu-file: make qemu_fflush and qemu_file_set_error private again, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 27/42] migration: detect error before sleeping, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 28/42] migration: remove useless qemu_file_get_error check, Paolo Bonzini, 2013/02/22
- [Qemu-devel] [PATCH 26/42] migration: eliminate last_round, Paolo Bonzini, 2013/02/22