[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v4 20/32] migration: synchronize dirty bitmap for re
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH v4 20/32] migration: synchronize dirty bitmap for resume |
Date: |
Wed, 8 Nov 2017 14:01:18 +0800 |
This patch implements the first part of core RAM resume logic for
postcopy. ram_resume_prepare() is provided for the work.
When the migration is interrupted by network failure, the dirty bitmap
on the source side will be meaningless, because even the dirty bit is
cleared, it is still possible that the sent page was lost along the way
to destination. Here instead of continue the migration with the old
dirty bitmap on source, we ask the destination side to send back its
received bitmap, then invert it to be our initial dirty bitmap.
The source side send thread will issue the MIG_CMD_RECV_BITMAP requests,
once per ramblock, to ask for the received bitmap. On destination side,
MIG_RP_MSG_RECV_BITMAP will be issued, along with the requested bitmap.
Data will be received on the return-path thread of source, and the main
migration thread will be notified when all the ramblock bitmaps are
synchronized.
Signed-off-by: Peter Xu <address@hidden>
---
migration/migration.c | 3 +++
migration/migration.h | 1 +
migration/ram.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
migration/trace-events | 4 ++++
4 files changed, 55 insertions(+)
diff --git a/migration/migration.c b/migration/migration.c
index 4dc34ed8ce..5b1fbe5b98 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2843,6 +2843,7 @@ static void migration_instance_finalize(Object *obj)
g_free(params->tls_hostname);
g_free(params->tls_creds);
qemu_sem_destroy(&ms->pause_sem);
+ qemu_sem_destroy(&ms->rp_state.rp_sem);
}
static void migration_instance_init(Object *obj)
@@ -2871,6 +2872,8 @@ static void migration_instance_init(Object *obj)
params->has_x_multifd_channels = true;
params->has_x_multifd_page_count = true;
params->has_xbzrle_cache_size = true;
+
+ qemu_sem_init(&ms->rp_state.rp_sem, 0);
}
/*
diff --git a/migration/migration.h b/migration/migration.h
index 11fbfebba1..82dd7d9820 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -108,6 +108,7 @@ struct MigrationState
QEMUFile *from_dst_file;
QemuThread rp_thread;
bool error;
+ QemuSemaphore rp_sem;
} rp_state;
double mbps;
diff --git a/migration/ram.c b/migration/ram.c
index b30c669476..49627ca9fc 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -49,6 +49,7 @@
#include "qemu/rcu_queue.h"
#include "migration/colo.h"
#include "migration/block.h"
+#include "savevm.h"
/***********************************************************/
/* ram save/restore */
@@ -3049,6 +3050,38 @@ static bool ram_has_postcopy(void *opaque)
return migrate_postcopy_ram();
}
+/* Sync all the dirty bitmap with destination VM. */
+static int ram_dirty_bitmap_sync_all(MigrationState *s, RAMState *rs)
+{
+ RAMBlock *block;
+ QEMUFile *file = s->to_dst_file;
+ int ramblock_count = 0;
+
+ trace_ram_dirty_bitmap_sync_start();
+
+ RAMBLOCK_FOREACH(block) {
+ qemu_savevm_send_recv_bitmap(file, block->idstr);
+ trace_ram_dirty_bitmap_request(block->idstr);
+ ramblock_count++;
+ }
+
+ trace_ram_dirty_bitmap_sync_wait();
+
+ /* Wait until all the ramblocks' dirty bitmap synced */
+ while (ramblock_count--) {
+ qemu_sem_wait(&s->rp_state.rp_sem);
+ }
+
+ trace_ram_dirty_bitmap_sync_complete();
+
+ return 0;
+}
+
+static void ram_dirty_bitmap_reload_notify(MigrationState *s)
+{
+ qemu_sem_post(&s->rp_state.rp_sem);
+}
+
/*
* Read the received bitmap, revert it as the initial dirty bitmap.
* This is only used when the postcopy migration is paused but wants
@@ -3123,12 +3156,25 @@ int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock
*block)
trace_ram_dirty_bitmap_reload_complete(block->idstr);
+ /*
+ * We succeeded to sync bitmap for current ramblock. If this is
+ * the last one to sync, we need to notify the main send thread.
+ */
+ ram_dirty_bitmap_reload_notify(s);
+
ret = 0;
out:
free(le_bitmap);
return ret;
}
+static int ram_resume_prepare(MigrationState *s, void *opaque)
+{
+ RAMState *rs = *(RAMState **)opaque;
+
+ return ram_dirty_bitmap_sync_all(s, rs);
+}
+
static SaveVMHandlers savevm_ram_handlers = {
.save_setup = ram_save_setup,
.save_live_iterate = ram_save_iterate,
@@ -3140,6 +3186,7 @@ static SaveVMHandlers savevm_ram_handlers = {
.save_cleanup = ram_save_cleanup,
.load_setup = ram_load_setup,
.load_cleanup = ram_load_cleanup,
+ .resume_prepare = ram_resume_prepare,
};
void ram_mig_init(void)
diff --git a/migration/trace-events b/migration/trace-events
index eadabf03e8..804f18d492 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -82,8 +82,12 @@ ram_load_postcopy_loop(uint64_t addr, int flags) "@%" PRIx64
" %x"
ram_postcopy_send_discard_bitmap(void) ""
ram_save_page(const char *rbname, uint64_t offset, void *host) "%s: offset:
0x%" PRIx64 " host: %p"
ram_save_queue_pages(const char *rbname, size_t start, size_t len) "%s: start:
0x%zx len: 0x%zx"
+ram_dirty_bitmap_request(char *str) "%s"
ram_dirty_bitmap_reload_begin(char *str) "%s"
ram_dirty_bitmap_reload_complete(char *str) "%s"
+ram_dirty_bitmap_sync_start(void) ""
+ram_dirty_bitmap_sync_wait(void) ""
+ram_dirty_bitmap_sync_complete(void) ""
# migration/migration.c
await_return_path_close_on_source_close(void) ""
--
2.13.6
- [Qemu-devel] [PATCH v4 04/32] migration: new postcopy-pause state, (continued)
- [Qemu-devel] [PATCH v4 04/32] migration: new postcopy-pause state, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 06/32] migration: allow dst vm pause on postcopy, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 08/32] migration: allow send_rq to fail, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 09/32] migration: allow fault thread to pause, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 10/32] qmp: hmp: add migrate "resume" option, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 11/32] migration: pass MigrationState to migrate_init(), Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 15/32] migration: new cmd MIG_CMD_RECV_BITMAP, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 17/32] migration: new cmd MIG_CMD_POSTCOPY_RESUME, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 18/32] migration: new message MIG_RP_MSG_RESUME_ACK, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 19/32] migration: introduce SaveVMHandlers.resume_prepare, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 20/32] migration: synchronize dirty bitmap for resume,
Peter Xu <=
- [Qemu-devel] [PATCH v4 21/32] migration: setup ramstate for resume, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 23/32] migration: free SocketAddress where allocated, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 22/32] migration: final handshake for the resume, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 26/32] migration: return incoming task tag for fd, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 27/32] migration: store listen task tag, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 29/32] migration: init dst in migration_object_init too, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 30/32] migration: delay the postcopy-active state switch, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 32/32] migration, hmp: new command "migrate_pause", Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 31/32] migration, qmp: new command "migrate-pause", Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 24/32] migration: return incoming task tag for sockets, Peter Xu, 2017/11/08