From: Bin Guo <[email protected]> multifd_send_sync_main() is called once per RAM synchronization round during live migration. It iterates over all multifd channels twice (signal loop + wait loop), calling migrate_multifd_channels() independently in each loop header.
Cache migrate_multifd_channels() in a local thread_count variable at function entry, matching the pattern already used in multifd_send_setup() and multifd_recv_setup(). This eliminates 2 redundant config lookups per sync call. Signed-off-by: Bin Guo <[email protected]> Reviewed-by: Fabiano Rosas <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Peter Xu <[email protected]> --- migration/multifd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index 0ac3f5e719..dbad525d2a 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -611,13 +611,15 @@ static int multifd_zero_copy_flush(QIOChannel *c) int multifd_send_sync_main(MultiFDSyncReq req) { int i; + int thread_count; bool flush_zero_copy; assert(req != MULTIFD_SYNC_NONE); + thread_count = migrate_multifd_channels(); flush_zero_copy = migrate_zero_copy_send(); - for (i = 0; i < migrate_multifd_channels(); i++) { + for (i = 0; i < thread_count; i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; if (multifd_send_should_exit()) { @@ -634,7 +636,7 @@ int multifd_send_sync_main(MultiFDSyncReq req) qatomic_set(&p->pending_sync, req); qemu_sem_post(&p->sem); } - for (i = 0; i < migrate_multifd_channels(); i++) { + for (i = 0; i < thread_count; i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; if (multifd_send_should_exit()) { -- 2.53.0
