From 64f615fe34b4d9e2487fbe61ecb7b4041fc6beb9 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Thu, 8 Feb 2018 18:31:06 +0800 Subject: [PATCH] migration: reuse mis->userfault_quit_fd 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. Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Peter Xu Message-Id: <20180208103132.28452-3-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert --- migration/migration.h | 6 ++++-- migration/postcopy-ram.c | 29 ++++++++++++++++++++--------- 2 files changed, 24 insertions(+), 11 deletions(-) diff --git a/migration/migration.h b/migration/migration.h index 848f638a20..75c72d3c8f 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 bec6c2c66b..9ad4f20f82 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -387,17 +387,18 @@ 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 { /* Not much we can do here, but may as well report it */ - error_report("%s: incrementing userfault_quit_fd: %s", __func__, + error_report("%s: incrementing userfault_event_fd: %s", __func__, strerror(errno)); } 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; } @@ -520,7 +521,7 @@ 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; @@ -530,8 +531,18 @@ 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 */ + if (read(mis->userfault_event_fd, &tmp64, 8) != 8) { + /* Nothing obviously nicer than posting this error. */ + error_report("%s: read() failed", __func__); + } + + if (atomic_read(&mis->fault_thread_quit)) { + trace_postcopy_ram_fault_thread_quit(); + break; + } } ret = read(mis->userfault_fd, &msg, sizeof(msg)); @@ -610,9 +621,9 @@ 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;