From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56837) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dcFeZ-0002Hl-Ef for qemu-devel@nongnu.org; Mon, 31 Jul 2017 14:42:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dcFeW-000402-9Q for qemu-devel@nongnu.org; Mon, 31 Jul 2017 14:42:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47300) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dcFeV-0003zX-W9 for qemu-devel@nongnu.org; Mon, 31 Jul 2017 14:42:52 -0400 Date: Mon, 31 Jul 2017 19:42:45 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20170731184244.GJ2122@work-vm> References: <1501229198-30588-1-git-send-email-peterx@redhat.com> <1501229198-30588-9-git-send-email-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1501229198-30588-9-git-send-email-peterx@redhat.com> Subject: Re: [Qemu-devel] [RFC 08/29] migration: reuse mis->userfault_quit_fd List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: qemu-devel@nongnu.org, Laurent Vivier , Alexey Perevalov , Juan Quintela , Andrea Arcangeli * Peter Xu (peterx@redhat.com) wrote: > 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 Reviewed-by: Dr. David Alan Gilbert > --- > 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 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK