Re: [libvirt] [PATCH 1/3] libxl: Receive migration data in a thread

On 13.11.2014 03:36, Jim Fehlig wrote: > The libxl driver receives migration data within an IO callback invoked > by the event loop, effectively disabling the event loop while migration > occurs. > > This patch moves receving of the migration data to a thread. The > incoming connection is still accepted in the IO callback, but control > is immediately returned to the event loop after spawning the thread. > > Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; > --- > src/libxl/libxl_migration.c | 60 > +++++++++++++++++++++++++++++++-------------- > 1 file changed, 42 insertions(+), 18 deletions(-) > > diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c > index 0b562f7..1940209 100644 > --- a/src/libxl/libxl_migration.c > +++ b/src/libxl/libxl_migration.c > @@ -35,6 +35,7 @@ > #include "vircommand.h" > #include "virstring.h" > #include "virobject.h" > +#include "virthread.h" > #include "rpc/virnetsocket.h" > #include "libxl_domain.h" > #include "libxl_driver.h" > @@ -48,6 +49,7 @@ VIR_LOG_INIT("libxl.libxl_migration"); > typedef struct _libxlMigrationDstArgs { > virObject parent; > > + int recvfd; > virConnectPtr conn; > virDomainObjPtr vm; > unsigned int flags; > @@ -82,31 +84,18 @@ libxlMigrationDstArgsOnceInit(void) > VIR_ONCE_GLOBAL_INIT(libxlMigrationDstArgs) > > static void > -libxlDoMigrateReceive(virNetSocketPtr sock, > - int events ATTRIBUTE_UNUSED, > - void *opaque) > +libxlDoMigrateReceive(void *opaque) > { > libxlMigrationDstArgs *args = opaque; > - virConnectPtr conn = args->conn; > virDomainObjPtr vm = args->vm; > virNetSocketPtr *socks = args->socks; > size_t nsocks = args->nsocks; > bool paused = args->flags & VIR_MIGRATE_PAUSED; > - libxlDriverPrivatePtr driver = conn->privateData; > - virNetSocketPtr client_sock; > - int recvfd = -1; > + libxlDriverPrivatePtr driver = args->conn->privateData; > + int recvfd = args->recvfd; > size_t i; > int ret; > > - if (virNetSocketAccept(sock, &client_sock) < 0) { > - virReportError(VIR_ERR_OPERATION_INVALID, "%s", > - _("Fail to accept migration connection")); > - goto cleanup; > - } > - VIR_DEBUG("Accepted migration connection\n"); > - recvfd = virNetSocketDupFD(client_sock, true); > - virObjectUnref(client_sock); > - > virObjectLock(vm); > ret = libxlDomainStart(driver, vm, paused, recvfd); > virObjectUnlock(vm); > @@ -114,7 +103,6 @@ libxlDoMigrateReceive(virNetSocketPtr sock, > if (ret < 0 && !vm->persistent) > virDomainObjListRemove(driver->domains, vm); > > - cleanup: > /* Remove all listen socks from event handler, and close them. */ > for (i = 0; i < nsocks; i++) { > virNetSocketUpdateIOCallback(socks[i], 0); > @@ -127,6 +115,42 @@ libxlDoMigrateReceive(virNetSocketPtr sock, > VIR_FORCE_CLOSE(recvfd); > } > > + > +static void > +libxlMigrateReceive(virNetSocketPtr sock, > + int events ATTRIBUTE_UNUSED, > + void *opaque) > +{ > + libxlMigrationDstArgs *args = opaque; > + virNetSocketPtr client_sock; > + int recvfd; > + virThread thread; > + > + /* Accept migration connection */ > + virNetSocketAccept(sock, &client_sock); > + if (client_sock == NULL) { > + virReportError(VIR_ERR_OPERATION_FAILED, "%s", > + _("Failed to accept migration connection")); > + return; > + } > + VIR_DEBUG("Accepted migration connection." > + " Spawing thread to process migration data"); > + recvfd = virNetSocketDupFD(client_sock, true); > + virObjectUnref(client_sock); > + > + /* > + * Avoid blocking the event loop. Start a thread to receive > + * the migration data > + */ > + args->recvfd = recvfd; > + if (virThreadCreate(&thread, false, > + libxlDoMigrateReceive, args) < 0) { > + virReportError(VIR_ERR_OPERATION_FAILED, "%s", > + _("Failed to create thread for receiving > migration data")); I believe you want VIR_FORCE_CLOSE(args->recvfd) in case thread creation failed.