From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52421) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YVLG7-0003p7-Eb for qemu-devel@nongnu.org; Tue, 10 Mar 2015 10:35:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YVLG0-0003rH-SA for qemu-devel@nongnu.org; Tue, 10 Mar 2015 10:35:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39571) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YVLG0-0003q2-Ka for qemu-devel@nongnu.org; Tue, 10 Mar 2015 10:35:40 -0400 Date: Tue, 10 Mar 2015 14:34:03 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20150310143402.GB18865@work-vm> References: <1424883128-9841-1-git-send-email-dgilbert@redhat.com> <1424883128-9841-12-git-send-email-dgilbert@redhat.com> <20150310054725.GC11973@voom.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150310054725.GC11973@voom.redhat.com> Subject: Re: [Qemu-devel] [PATCH v5 11/45] Return path: Send responses from destination to source List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, quintela@redhat.com, qemu-devel@nongnu.org, amit.shah@redhat.com, pbonzini@redhat.com, yanghy@cn.fujitsu.com * David Gibson (david@gibson.dropbear.id.au) wrote: > On Wed, Feb 25, 2015 at 04:51:34PM +0000, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" > > > > Add migrate_send_rp_message to send a message from destination to source along the return path. > > (It uses a mutex to let it be called from multiple threads) > > Add migrate_send_rp_shut to send a 'shut' message to indicate > > the destination is finished with the RP. > > Add migrate_send_rp_ack to send a 'PONG' message in response to a PING > > Use it in the CMD_PING handler > > > > Signed-off-by: Dr. David Alan Gilbert > > --- > > include/migration/migration.h | 17 ++++++++++++++++ > > migration/migration.c | 45 +++++++++++++++++++++++++++++++++++++++++++ > > savevm.c | 2 +- > > trace-events | 1 + > > 4 files changed, 64 insertions(+), 1 deletion(-) > > > > diff --git a/include/migration/migration.h b/include/migration/migration.h > > index c514dd4..6775747 100644 > > --- a/include/migration/migration.h > > +++ b/include/migration/migration.h > > @@ -41,6 +41,13 @@ struct MigrationParams { > > bool shared; > > }; > > > > +/* Commands sent on the return path from destination to source*/ > > +enum mig_rpcomm_cmd { > > "command" doesn't seem like quite the right description for these rp > messages. Would you prefer 'message' ? > > + MIG_RP_CMD_INVALID = 0, /* Must be 0 */ > > + MIG_RP_CMD_SHUT, /* sibling will not send any more RP messages */ > > + MIG_RP_CMD_PONG, /* Response to a PING; data (seq: be32 ) */ > > +}; > > + > > typedef struct MigrationState MigrationState; > > > > /* State for the incoming migration */ > > @@ -48,6 +55,7 @@ struct MigrationIncomingState { > > QEMUFile *file; > > > > QEMUFile *return_path; > > + QemuMutex rp_mutex; /* We send replies from multiple threads */ > > }; > > > > MigrationIncomingState *migration_incoming_get_current(void); > > @@ -169,6 +177,15 @@ int64_t migrate_xbzrle_cache_size(void); > > > > int64_t xbzrle_cache_resize(int64_t new_size); > > > > +/* Sending on the return path - generic and then for each message type */ > > +void migrate_send_rp_message(MigrationIncomingState *mis, > > + enum mig_rpcomm_cmd cmd, > > + uint16_t len, uint8_t *data); > > +void migrate_send_rp_shut(MigrationIncomingState *mis, > > + uint32_t value); > > +void migrate_send_rp_pong(MigrationIncomingState *mis, > > + uint32_t value); > > + > > void ram_control_before_iterate(QEMUFile *f, uint64_t flags); > > void ram_control_after_iterate(QEMUFile *f, uint64_t flags); > > void ram_control_load_hook(QEMUFile *f, uint64_t flags); > > diff --git a/migration/migration.c b/migration/migration.c > > index a36ea65..80d234c 100644 > > --- a/migration/migration.c > > +++ b/migration/migration.c > > @@ -78,6 +78,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f) > > { > > mis_current = g_malloc0(sizeof(MigrationIncomingState)); > > mis_current->file = f; > > + qemu_mutex_init(&mis_current->rp_mutex); > > > > return mis_current; > > } > > @@ -88,6 +89,50 @@ void migration_incoming_state_destroy(void) > > mis_current = NULL; > > } > > > > +/* > > + * Send a message on the return channel back to the source > > + * of the migration. > > + */ > > +void migrate_send_rp_message(MigrationIncomingState *mis, > > + enum mig_rpcomm_cmd cmd, > > + uint16_t len, uint8_t *data) > > Using (void *) for data would avoid casts in a bunch of the callers. Fixed; thanks. > > +{ > > + trace_migrate_send_rp_message((int)cmd, len); > > + qemu_mutex_lock(&mis->rp_mutex); > > + qemu_put_be16(mis->return_path, (unsigned int)cmd); > > + qemu_put_be16(mis->return_path, len); > > + qemu_put_buffer(mis->return_path, data, len); > > + qemu_fflush(mis->return_path); > > + qemu_mutex_unlock(&mis->rp_mutex); > > +} > > + > > +/* > > + * Send a 'SHUT' message on the return channel with the given value > > + * to indicate that we've finished with the RP. None-0 value indicates > > + * error. > > + */ > > +void migrate_send_rp_shut(MigrationIncomingState *mis, > > + uint32_t value) > > +{ > > + uint32_t buf; > > + > > + buf = cpu_to_be32(value); > > + migrate_send_rp_message(mis, MIG_RP_CMD_SHUT, 4, (uint8_t *)&buf); > > ^ sizeof(buf) > would be safer Done. > > +} > > + > > +/* > > + * Send a 'PONG' message on the return channel with the given value > > + * (normally in response to a 'PING') > > + */ > > +void migrate_send_rp_pong(MigrationIncomingState *mis, > > + uint32_t value) > > +{ > > + uint32_t buf; > > + > > + buf = cpu_to_be32(value); > > + migrate_send_rp_message(mis, MIG_RP_CMD_PONG, 4, (uint8_t *)&buf); > > It occurs to me that you could define PONG as returning the whole > buffer that PING sends, instead of just 4-bytes. Might allow for some > more testing of variable sized messages. Yes; although it would complicate things a lot if I made it fully generic because I'd have to worry about allocating a buffer etc and I'm not making vast use of the 4 bytes I've already got. Dave > > > +} > > + > > void qemu_start_incoming_migration(const char *uri, Error **errp) > > { > > const char *p; > > diff --git a/savevm.c b/savevm.c > > index d082738..7084d07 100644 > > --- a/savevm.c > > +++ b/savevm.c > > @@ -1008,7 +1008,7 @@ static int loadvm_process_command(QEMUFile *f) > > tmp32); > > return -1; > > } > > - /* migrate_send_rp_pong(mis, tmp32); TODO: gets added later */ > > + migrate_send_rp_pong(mis, tmp32); > > break; > > > > default: > > diff --git a/trace-events b/trace-events > > index 99e00b5..4f3eff8 100644 > > --- a/trace-events > > +++ b/trace-events > > @@ -1379,6 +1379,7 @@ migrate_fd_cleanup(void) "" > > migrate_fd_error(void) "" > > migrate_fd_cancel(void) "" > > migrate_pending(uint64_t size, uint64_t max) "pending size %" PRIu64 " max %" PRIu64 > > +migrate_send_rp_message(int cmd, uint16_t len) "cmd=%d, len=%d" > > migrate_transferred(uint64_t tranferred, uint64_t time_spent, double bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %g max_size %" PRId64 > > > > # migration/rdma.c > > -- > David Gibson | I'll have my music baroque, and my code > david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ > | _way_ _around_! > http://www.ozlabs.org/~dgibson -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK