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migration: Remember num of ramblocks to sync during recovery

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Instead of only relying on the count of rp_sem, make the counter be part of
RAMState so it can be used in both threads to synchronize on the process.

rp_sem will be further reused in follow up patches, as a way to kick the
main thread, e.g., on recovery failures.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-7-peterx@redhat.com>
This commit is contained in:
Peter Xu 2023-10-04 18:02:36 -04:00 committed by Juan Quintela
parent f4b897f485
commit 1015ff5476
1 changed files with 14 additions and 3 deletions
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17
migration/ram.c
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@ -394,6 +394,14 @@ struct RAMState {
/* Queue of outstanding page requests from the destination */
QemuMutex src_page_req_mutex;
QSIMPLEQ_HEAD(, RAMSrcPageRequest) src_page_requests;
/*
* This is only used when postcopy is in recovery phase, to communicate
* between the migration thread and the return path thread on dirty
* bitmap synchronizations. This field is unused in other stages of
* RAM migration.
*/
unsigned int postcopy_bmap_sync_requested;
};
typedef struct RAMState RAMState;
@ -4119,20 +4127,20 @@ 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();
qatomic_set(&rs->postcopy_bmap_sync_requested, 0);
RAMBLOCK_FOREACH_NOT_IGNORED(block) {
qemu_savevm_send_recv_bitmap(file, block->idstr);
trace_ram_dirty_bitmap_request(block->idstr);
ramblock_count++;
qatomic_inc(&rs->postcopy_bmap_sync_requested);
}
trace_ram_dirty_bitmap_sync_wait();
/* Wait until all the ramblocks' dirty bitmap synced */
while (ramblock_count--) {
while (qatomic_read(&rs->postcopy_bmap_sync_requested)) {
qemu_sem_wait(&s->rp_state.rp_sem);
}
@ -4159,6 +4167,7 @@ int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *block)
unsigned long *le_bitmap, nbits = block->used_length >> TARGET_PAGE_BITS;
uint64_t local_size = DIV_ROUND_UP(nbits, 8);
uint64_t size, end_mark;
RAMState *rs = ram_state;
trace_ram_dirty_bitmap_reload_begin(block->idstr);
@ -4225,6 +4234,8 @@ int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *block)
/* We'll recalculate migration_dirty_pages in ram_state_resume_prepare(). */
trace_ram_dirty_bitmap_reload_complete(block->idstr);
qatomic_dec(&rs->postcopy_bmap_sync_requested);
/*
* We succeeded to sync bitmap for current ramblock. If this is
* the last one to sync, we need to notify the main send thread.