24e289d025
Move qemu_savevm_state_{header,setup} into the main loop and
the rest of the iteration into a coroutine. The former need
to lock the iothread (and we can't unlock it in the
coroutine), and the latter can't deal with being in a
separate thread, so a coroutine it must be.
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
112 lines
3.9 KiB
Diff
112 lines
3.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Wolfgang Bumiller <w.bumiller@proxmox.com>
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Date: Thu, 30 Apr 2020 15:55:37 +0200
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Subject: [PATCH] move savevm-async back into a coroutine
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Move qemu_savevm_state_{header,setup} into the main loop and
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the rest of the iteration into a coroutine. The former need
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to lock the iothread (and we can't unlock it in the
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coroutine), and the latter can't deal with being in a
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separate thread, so a coroutine it must be.
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Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
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---
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savevm-async.c | 28 +++++++++-------------------
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1 file changed, 9 insertions(+), 19 deletions(-)
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diff --git a/savevm-async.c b/savevm-async.c
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index a38b15d652..af865b9a0a 100644
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--- a/savevm-async.c
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+++ b/savevm-async.c
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@@ -51,7 +51,7 @@ static struct SnapshotState {
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QEMUFile *file;
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int64_t total_time;
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QEMUBH *cleanup_bh;
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- QemuThread thread;
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+ Coroutine *co;
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} snap_state;
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SaveVMInfo *qmp_query_savevm(Error **errp)
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@@ -201,11 +201,9 @@ static void process_savevm_cleanup(void *opaque)
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int ret;
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qemu_bh_delete(snap_state.cleanup_bh);
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snap_state.cleanup_bh = NULL;
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+ snap_state.co = NULL;
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qemu_savevm_state_cleanup();
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- qemu_mutex_unlock_iothread();
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- qemu_thread_join(&snap_state.thread);
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- qemu_mutex_lock_iothread();
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ret = save_snapshot_cleanup();
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if (ret < 0) {
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save_snapshot_error("save_snapshot_cleanup error %d", ret);
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@@ -221,18 +219,13 @@ static void process_savevm_cleanup(void *opaque)
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}
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}
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-static void *process_savevm_thread(void *opaque)
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+static void process_savevm_coro(void *opaque)
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{
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int ret;
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int64_t maxlen;
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MigrationState *ms = migrate_get_current();
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- rcu_register_thread();
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-
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- qemu_savevm_state_header(snap_state.file);
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- qemu_savevm_state_setup(snap_state.file);
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ret = qemu_file_get_error(snap_state.file);
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-
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if (ret < 0) {
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save_snapshot_error("qemu_savevm_state_setup failed");
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goto out;
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@@ -247,16 +240,13 @@ static void *process_savevm_thread(void *opaque)
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maxlen = blk_getlength(snap_state.target) - 30*1024*1024;
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if (pending_size > 400000 && snap_state.bs_pos + pending_size < maxlen) {
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- qemu_mutex_lock_iothread();
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ret = qemu_savevm_state_iterate(snap_state.file, false);
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if (ret < 0) {
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save_snapshot_error("qemu_savevm_state_iterate error %d", ret);
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break;
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}
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- qemu_mutex_unlock_iothread();
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DPRINTF("savevm inerate pending size %lu ret %d\n", pending_size, ret);
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} else {
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- qemu_mutex_lock_iothread();
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qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
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ret = global_state_store();
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if (ret) {
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@@ -285,16 +275,12 @@ static void *process_savevm_thread(void *opaque)
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}
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qemu_bh_schedule(snap_state.cleanup_bh);
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- qemu_mutex_unlock_iothread();
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out:
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/* set migration state accordingly and clear soon-to-be stale file */
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migrate_set_state(&ms->state, MIGRATION_STATUS_SETUP,
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ret ? MIGRATION_STATUS_FAILED : MIGRATION_STATUS_COMPLETED);
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ms->to_dst_file = NULL;
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-
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- rcu_unregister_thread();
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- return NULL;
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}
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void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
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@@ -373,8 +359,12 @@ void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
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snap_state.state = SAVE_STATE_ACTIVE;
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snap_state.cleanup_bh = qemu_bh_new(process_savevm_cleanup, &snap_state);
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- qemu_thread_create(&snap_state.thread, "savevm-async", process_savevm_thread,
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- NULL, QEMU_THREAD_JOINABLE);
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+ snap_state.co = qemu_coroutine_create(&process_savevm_coro, NULL);
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+ qemu_mutex_unlock_iothread();
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+ qemu_savevm_state_header(snap_state.file);
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+ qemu_savevm_state_setup(snap_state.file);
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+ qemu_mutex_lock_iothread();
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+ aio_co_schedule(iohandler_get_aio_context(), snap_state.co);
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return;
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