It was only used for quitting the page fault thread before. Let it be something more useful - now we can use it to notify a "wake" for the page fault thread (for any reason), and it only means "quit" if the fault_thread_quit is set.
Since we changed what it does, renaming it to userfault_event_fd. Signed-off-by: Peter Xu <pet...@redhat.com> --- migration/migration.h | 6 ++++-- migration/postcopy-ram.c | 24 ++++++++++++++++-------- 2 files changed, 20 insertions(+), 10 deletions(-) diff --git a/migration/migration.h b/migration/migration.h index 148c9fa..70e3094 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -35,6 +35,8 @@ struct MigrationIncomingState { bool have_fault_thread; QemuThread fault_thread; QemuSemaphore fault_thread_sem; + /* Set this when we want the fault thread to quit */ + bool fault_thread_quit; bool have_listen_thread; QemuThread listen_thread; @@ -42,8 +44,8 @@ struct MigrationIncomingState { /* For the kernel to send us notifications */ int userfault_fd; - /* To tell the fault_thread to quit */ - int userfault_quit_fd; + /* To notify the fault_thread to wake, e.g., when need to quit */ + int userfault_event_fd; QEMUFile *to_src_file; QemuMutex rp_mutex; /* We send replies from multiple threads */ void *postcopy_tmp_page; diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 952b73a..4278fe7 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -305,7 +305,8 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) * currently be at 0, we're going to increment it to 1 */ tmp64 = 1; - if (write(mis->userfault_quit_fd, &tmp64, 8) == 8) { + atomic_set(&mis->fault_thread_quit, 1); + if (write(mis->userfault_event_fd, &tmp64, 8) == 8) { trace_postcopy_ram_incoming_cleanup_join(); qemu_thread_join(&mis->fault_thread); } else { @@ -315,7 +316,7 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) } trace_postcopy_ram_incoming_cleanup_closeuf(); close(mis->userfault_fd); - close(mis->userfault_quit_fd); + close(mis->userfault_event_fd); mis->have_fault_thread = false; } @@ -438,7 +439,7 @@ static void *postcopy_ram_fault_thread(void *opaque) pfd[0].fd = mis->userfault_fd; pfd[0].events = POLLIN; pfd[0].revents = 0; - pfd[1].fd = mis->userfault_quit_fd; + pfd[1].fd = mis->userfault_event_fd; pfd[1].events = POLLIN; /* Waiting for eventfd to go positive */ pfd[1].revents = 0; @@ -448,8 +449,15 @@ static void *postcopy_ram_fault_thread(void *opaque) } if (pfd[1].revents) { - trace_postcopy_ram_fault_thread_quit(); - break; + uint64_t tmp64 = 0; + + /* Consume the signal */ + read(mis->userfault_event_fd, &tmp64, 8); + + if (atomic_read(&mis->fault_thread_quit)) { + trace_postcopy_ram_fault_thread_quit(); + break; + } } ret = read(mis->userfault_fd, &msg, sizeof(msg)); @@ -528,9 +536,9 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis) } /* Now an eventfd we use to tell the fault-thread to quit */ - mis->userfault_quit_fd = eventfd(0, EFD_CLOEXEC); - if (mis->userfault_quit_fd == -1) { - error_report("%s: Opening userfault_quit_fd: %s", __func__, + mis->userfault_event_fd = eventfd(0, EFD_CLOEXEC); + if (mis->userfault_event_fd == -1) { + error_report("%s: Opening userfault_event_fd: %s", __func__, strerror(errno)); close(mis->userfault_fd); return -1; -- 2.7.4