diff options
Diffstat (limited to 'migration/ram.c')
| -rw-r--r-- | migration/ram.c | 89 |
1 files changed, 39 insertions, 50 deletions
diff --git a/migration/ram.c b/migration/ram.c index a60666d3f6..ce28328141 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -72,27 +72,6 @@ /* ram save/restore */ /* - * RAM_SAVE_FLAG_ZERO used to be named RAM_SAVE_FLAG_COMPRESS, it - * worked for pages that were filled with the same char. We switched - * it to only search for the zero value. And to avoid confusion with - * RAM_SAVE_FLAG_COMPRESS_PAGE just rename it. - * - * RAM_SAVE_FLAG_FULL was obsoleted in 2009. - * - * RAM_SAVE_FLAG_COMPRESS_PAGE (0x100) was removed in QEMU 9.1. - */ -#define RAM_SAVE_FLAG_FULL 0x01 -#define RAM_SAVE_FLAG_ZERO 0x02 -#define RAM_SAVE_FLAG_MEM_SIZE 0x04 -#define RAM_SAVE_FLAG_PAGE 0x08 -#define RAM_SAVE_FLAG_EOS 0x10 -#define RAM_SAVE_FLAG_CONTINUE 0x20 -#define RAM_SAVE_FLAG_XBZRLE 0x40 -/* 0x80 is reserved in rdma.h for RAM_SAVE_FLAG_HOOK */ -#define RAM_SAVE_FLAG_MULTIFD_FLUSH 0x200 -/* We can't use any flag that is bigger than 0x200 */ - -/* * mapped-ram migration supports O_DIRECT, so we need to make sure the * userspace buffer, the IO operation size and the file offset are * aligned according to the underlying device's block size. The first @@ -1323,19 +1302,12 @@ static int find_dirty_block(RAMState *rs, PageSearchStatus *pss) pss->page = 0; pss->block = QLIST_NEXT_RCU(pss->block, next); if (!pss->block) { - if (migrate_multifd() && - (!migrate_multifd_flush_after_each_section() || - migrate_mapped_ram())) { + if (multifd_ram_sync_per_round()) { QEMUFile *f = rs->pss[RAM_CHANNEL_PRECOPY].pss_channel; - int ret = multifd_ram_flush_and_sync(); + int ret = multifd_ram_flush_and_sync(f); if (ret < 0) { return ret; } - - if (!migrate_mapped_ram()) { - qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH); - qemu_fflush(f); - } } /* Hit the end of the list */ @@ -3064,19 +3036,39 @@ static int ram_save_setup(QEMUFile *f, void *opaque, Error **errp) migration_ops->ram_save_target_page = ram_save_target_page_legacy; } + /* + * This operation is unfortunate.. + * + * For legacy QEMUs using per-section sync + * ======================================= + * + * This must exist because the EOS below requires the SYNC messages + * per-channel to work. + * + * For modern QEMUs using per-round sync + * ===================================== + * + * Logically such sync is not needed, and recv threads should not run + * until setup ready (using things like channels_ready on src). Then + * we should be all fine. + * + * However even if we add channels_ready to recv side in new QEMUs, old + * QEMU won't have them so this sync will still be needed to make sure + * multifd recv threads won't start processing guest pages early before + * ram_load_setup() is properly done. + * + * Let's stick with this. Fortunately the overhead is low to sync + * during setup because the VM is running, so at least it's not + * accounted as part of downtime. + */ bql_unlock(); - ret = multifd_ram_flush_and_sync(); + ret = multifd_ram_flush_and_sync(f); bql_lock(); if (ret < 0) { error_setg(errp, "%s: multifd synchronization failed", __func__); return ret; } - if (migrate_multifd() && !migrate_multifd_flush_after_each_section() - && !migrate_mapped_ram()) { - qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH); - } - qemu_put_be64(f, RAM_SAVE_FLAG_EOS); ret = qemu_fflush(f); if (ret < 0) { @@ -3209,9 +3201,8 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) out: if (ret >= 0 && migration_is_running()) { - if (migrate_multifd() && migrate_multifd_flush_after_each_section() && - !migrate_mapped_ram()) { - ret = multifd_ram_flush_and_sync(); + if (multifd_ram_sync_per_section()) { + ret = multifd_ram_flush_and_sync(f); if (ret < 0) { return ret; } @@ -3283,9 +3274,15 @@ static int ram_save_complete(QEMUFile *f, void *opaque) } } - ret = multifd_ram_flush_and_sync(); - if (ret < 0) { - return ret; + if (multifd_ram_sync_per_section()) { + /* + * Only the old dest QEMU will need this sync, because each EOS + * will require one SYNC message on each channel. + */ + ret = multifd_ram_flush_and_sync(f); + if (ret < 0) { + return ret; + } } if (migrate_mapped_ram()) { @@ -3796,15 +3793,7 @@ int ram_load_postcopy(QEMUFile *f, int channel) TARGET_PAGE_SIZE); } break; - case RAM_SAVE_FLAG_MULTIFD_FLUSH: - multifd_recv_sync_main(); - break; case RAM_SAVE_FLAG_EOS: - /* normal exit */ - if (migrate_multifd() && - migrate_multifd_flush_after_each_section()) { - multifd_recv_sync_main(); - } break; default: error_report("Unknown combination of migration flags: 0x%x" |