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Berrange" , "Dr . David Alan Gilbert" , Leonardo Bras Soares Passos Subject: Re: [PATCH v2 1/3] migration: Rework multi-channel checks on URI In-Reply-To: <20230202212458.726496-2-peterx@redhat.com> (Peter Xu's message of "Thu, 2 Feb 2023 16:24:56 -0500") References: <20230202212458.726496-1-peterx@redhat.com> <20230202212458.726496-2-peterx@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) Date: Wed, 08 Feb 2023 20:19:11 +0100 Message-ID: <87pmak9d8w.fsf@secure.mitica> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=170.10.129.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Xu wrote: > The whole idea of multi-channel checks was not properly done, IMHO. > > Currently we check multi-channel in a lot of places, but actually that's > not needed because we only need to check it right after we get the URI and > that should be it. > > If the URI check succeeded, we should never need to check it again because > we must have it. If it check fails, we should fail immediately on either > the qmp_migrate or qmp_migrate_incoming, instead of failingg it later after > the connection established. > > Neither should we fail any set capabiliities like what we used to do here: > > 5ad15e8614 ("migration: allow enabling mutilfd for specific protocol only", 2021-10-19) > > Because logically the URI will only be set later after the capability is > set, so it doesn't make a lot of sense to check the URI type when setting > the capability, because we're checking the cap with an old URI passed in, > and that may not even be the URI we're going to use later. > > This patch mostly reverted all such checks for before, dropping the > variable migrate_allow_multi_channels and helpers. Instead, add a common > helper to check URI for multi-channels for either qmp_migrate and > qmp_migrate_incoming and that should do all the proper checks. The failure > will only trigger with the "migrate" or "migrate_incoming" command, or when > user specified "-incoming xxx" where "xxx" is not "defer". > > With that, make postcopy_preempt_setup() as simple as creating the channel. > > Signed-off-by: Peter Xu The idea is right. But I think that changing everything in a single patch is confusing. > --- > migration/migration.c | 56 +++++++++++++++++++--------------------- > migration/migration.h | 3 --- > migration/multifd.c | 12 ++------- > migration/postcopy-ram.c | 14 +--------- > migration/postcopy-ram.h | 2 +- > 5 files changed, 31 insertions(+), 56 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index f4f7d207f0..ef7fceb5d7 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -182,16 +182,26 @@ static int migration_maybe_pause(MigrationState *s, > int new_state); > static void migrate_fd_cancel(MigrationState *s); > > -static bool migrate_allow_multi_channels = true; > +static bool migration_needs_multiple_sockets(void) > +{ > + return migrate_use_multifd() || migrate_postcopy_preempt(); > +} This function (and use it) makes sense > -void migrate_protocol_allow_multi_channels(bool allow) > +static bool uri_supports_multi_channels(const char *uri) > { > - migrate_allow_multi_channels = allow; > + return strstart(uri, "tcp:", NULL) || strstart(uri, "unix:", NULL) || > + strstart(uri, "vsock:", NULL); Indentation is wrong. Fixing it by hand. This other is also ok with me. > } > > -bool migrate_multi_channels_is_allowed(void) > +static bool migration_uri_validate(const char *uri, Error **errp) > { > - return migrate_allow_multi_channels; > + if (migration_needs_multiple_sockets() && > + !uri_supports_multi_channels(uri)) { > + error_setg(errp, "Migration requires multi-channel URIs (e.g. tcp)"); > + return false; > + } > + > + return true; > } This name is not O:-) What about: migration_channels_and_uri_compatible() No, it is not perfect, but I can think anything else. But validate don't mean anything. I can't know without looking at the function what is the meaning of the result. > static gint page_request_addr_cmp(gconstpointer ap, gconstpointer bp) > @@ -491,12 +501,15 @@ static void qemu_start_incoming_migration(const char *uri, Error **errp) > { > const char *p = NULL; > > - migrate_protocol_allow_multi_channels(false); /* reset it anyway */ > + /* URI is not suitable for migration? */ > + if (!migration_uri_validate(uri, errp)) { > + return; > + } > + > qapi_event_send_migration(MIGRATION_STATUS_SETUP); > if (strstart(uri, "tcp:", &p) || > strstart(uri, "unix:", NULL) || > strstart(uri, "vsock:", NULL)) { > - migrate_protocol_allow_multi_channels(true); > socket_start_incoming_migration(p ? p : uri, errp); > #ifdef CONFIG_RDMA > } else if (strstart(uri, "rdma:", &p)) { > @@ -721,11 +734,6 @@ void migration_fd_process_incoming(QEMUFile *f, Error **errp) > migration_incoming_process(); > } > > -static bool migration_needs_multiple_sockets(void) > -{ > - return migrate_use_multifd() || migrate_postcopy_preempt(); > -} > - > void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp) > { > MigrationIncomingState *mis = migration_incoming_get_current(); > @@ -1347,15 +1355,6 @@ static bool migrate_caps_check(bool *cap_list, > } > #endif > > - > - /* incoming side only */ > - if (runstate_check(RUN_STATE_INMIGRATE) && > - !migrate_multi_channels_is_allowed() && > - cap_list[MIGRATION_CAPABILITY_MULTIFD]) { > - error_setg(errp, "multifd is not supported by current protocol"); > - return false; > - } > - > if (cap_list[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT]) { > if (!cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]) { > error_setg(errp, "Postcopy preempt requires postcopy-ram"); > @@ -2440,6 +2439,11 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk, > MigrationState *s = migrate_get_current(); > const char *p = NULL; > > + /* URI is not suitable for migration? */ > + if (!migration_uri_validate(uri, errp)) { > + return; > + } > + > if (!migrate_prepare(s, has_blk && blk, has_inc && inc, > has_resume && resume, errp)) { > /* Error detected, put into errp */ > @@ -2452,11 +2456,9 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk, > } > } > > - migrate_protocol_allow_multi_channels(false); > if (strstart(uri, "tcp:", &p) || > strstart(uri, "unix:", NULL) || > strstart(uri, "vsock:", NULL)) { > - migrate_protocol_allow_multi_channels(true); > socket_start_outgoing_migration(s, p ? p : uri, &local_err); > #ifdef CONFIG_RDMA > } else if (strstart(uri, "rdma:", &p)) { > @@ -4309,12 +4311,8 @@ void migrate_fd_connect(MigrationState *s, Error *error_in) > } > > /* This needs to be done before resuming a postcopy */ > - if (postcopy_preempt_setup(s, &local_err)) { > - error_report_err(local_err); > - migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, > - MIGRATION_STATUS_FAILED); > - migrate_fd_cleanup(s); > - return; > + if (migrate_postcopy_preempt()) { > + postcopy_preempt_setup(s); > } I think that this should go in a different patch. Rest looks ok. Thanks, Juan.