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envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.191, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Feb 19, 2025 at 09:39:38AM +0000, Zhijian Li (Fujitsu) wrote: > > > On 19/02/2025 06:03, Peter Xu wrote: > > On Tue, Feb 18, 2025 at 05:30:40PM -0300, Fabiano Rosas wrote: > >> Li Zhijian via writes: > >> > >>> Address an error in RDMA-based migration by ensuring RDMA is prioritized > >>> when saving pages in `ram_save_target_page()`. > >>> > >>> Previously, the RDMA protocol's page-saving step was placed after other > >>> protocols due to a refactoring in commit bc38dc2f5f3. This led to migration > >>> failures characterized by unknown control messages and state loading errors > >>> destination: > >>> (qemu) qemu-system-x86_64: Unknown control message QEMU FILE > >>> qemu-system-x86_64: error while loading state section id 1(ram) > >>> qemu-system-x86_64: load of migration failed: Operation not permitted > >>> source: > >>> (qemu) qemu-system-x86_64: RDMA is in an error state waiting migration to abort! > >>> qemu-system-x86_64: failed to save SaveStateEntry with id(name): 1(ram): -1 > >>> qemu-system-x86_64: rdma migration: recv polling control error! > >>> qemu-system-x86_64: warning: Early error. Sending error. > >>> qemu-system-x86_64: warning: rdma migration: send polling control error > >>> > >>> RDMA migration implemented its own protocol/method to send pages to > >>> destination side, hand over to RDMA first to prevent pages being saved by > >>> other protocol. > >>> > >>> Fixes: bc38dc2f5f3 ("migration: refactor ram_save_target_page functions") > >>> Signed-off-by: Li Zhijian > >>> --- > >>> migration/ram.c | 9 +++++---- > >>> 1 file changed, 5 insertions(+), 4 deletions(-) > >>> > >>> diff --git a/migration/ram.c b/migration/ram.c > >>> index 6f460fd22d2..635a2fe443a 100644 > >>> --- a/migration/ram.c > >>> +++ b/migration/ram.c > >>> @@ -1964,6 +1964,11 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) > >>> ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS; > >>> int res; > >>> > >>> + /* Hand over to RDMA first */ > >>> + if (control_save_page(pss, offset, &res)) { > >>> + return res; > >>> + } > >>> + > >> > >> Can we hoist that migrate_rdma() from inside the function? Since the > >> other paths already check first before calling their functions. > > > > Yeah, it sounds good to me. > > > > If we're talking about hoist and stuff.. and if we want to go slightly > > further, I wonder if we could also drop RAM_SAVE_CONTROL_NOT_SUPP. > > > > if (!migrate_rdma() || migration_in_postcopy()) { > > return RAM_SAVE_CONTROL_NOT_SUPP; > > } > > > > We should make sure rdma_control_save_page() won't get invoked at all in > > either case above.. > > > For postcopy, maybe we could fail in the QMP migrate / > > migrate_incoming cmd, at migration_channels_and_transport_compatible() > > I tried to kill RAM_SAVE_CONTROL_NOT_SUPP, but It seems it doesn't need to touch any postcopy logic > "in the QMP migrate / migrate_incoming cmd, at migration_channels_and_transport_compatible()" > > Is there something I might have overlooked? Yes it looks almost good. What I meant is (please see below): > > A whole draft diff would be like below: > It includes 3 parts: > > migration/rdma: Remove unnecessary RAM_SAVE_CONTROL_NOT_SUPP check in rdma_control_save_page() > migration: kill RAM_SAVE_CONTROL_NOT_SUPP > migration: open control_save_page() to ram_save_target_page() > > diff --git a/migration/ram.c b/migration/ram.c > index 589b6505eb2..fc6a964fd64 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1143,32 +1143,6 @@ static int save_zero_page(RAMState *rs, PageSearchStatus *pss, > return len; > } > > -/* > - * @pages: the number of pages written by the control path, > - * < 0 - error > - * > 0 - number of pages written > - * > - * Return true if the pages has been saved, otherwise false is returned. > - */ > -static bool control_save_page(PageSearchStatus *pss, > - ram_addr_t offset, int *pages) > -{ > - int ret; > - > - ret = rdma_control_save_page(pss->pss_channel, pss->block->offset, offset, > - TARGET_PAGE_SIZE); > - if (ret == RAM_SAVE_CONTROL_NOT_SUPP) { > - return false; > - } > - > - if (ret == RAM_SAVE_CONTROL_DELAYED) { > - *pages = 1; > - return true; > - } > - *pages = ret; > - return true; > -} > - > /* > * directly send the page to the stream > * > @@ -1964,6 +1938,16 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) > ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS; > int res; > > + if (migrate_rdma() && !migration_in_postcopy()) { Here instead of bypassing postcopy, we should fail the migrate cmd early if postcopy ever enabled: diff --git a/migration/migration.c b/migration/migration.c index 862f469ea7..3a82e71437 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -257,6 +257,12 @@ migration_channels_and_transport_compatible(MigrationAddress *addr, return false; } + if (addr->transport == MIGRATION_ADDRESS_TYPE_FILE && + migrate_postcopy_ram()) { + error_setg(errp, "RDMA migration doesn't support postcopy"); + return false; + } + return true; } > + res = rdma_control_save_page(pss->pss_channel, pss->block->offset, > + offset, TARGET_PAGE_SIZE); > + > + if (res == RAM_SAVE_CONTROL_DELAYED) { > + res = 1; > + } > + return res; > + } > + > if (!migrate_multifd() > || migrate_zero_page_detection() == ZERO_PAGE_DETECTION_LEGACY) { > if (save_zero_page(rs, pss, offset)) { > @@ -1976,10 +1960,6 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) > return ram_save_multifd_page(block, offset); > } > } > > - if (control_save_page(pss, offset, &res)) { > - return res; > - } > - > return ram_save_page(rs, pss); > } > > diff --git a/migration/rdma.c b/migration/rdma.c > index 76fb0349238..c6876347e1e 100644 > --- a/migration/rdma.c > +++ b/migration/rdma.c > @@ -3284,14 +3284,11 @@ err: > int rdma_control_save_page(QEMUFile *f, ram_addr_t block_offset, > ram_addr_t offset, size_t size) > { > - if (!migrate_rdma() || migration_in_postcopy()) { > - return RAM_SAVE_CONTROL_NOT_SUPP; > - } > + assert(migrate_rdma()); > > int ret = qemu_rdma_save_page(f, block_offset, offset, size); > > - if (ret != RAM_SAVE_CONTROL_DELAYED && > - ret != RAM_SAVE_CONTROL_NOT_SUPP) { > + if (ret != RAM_SAVE_CONTROL_DELAYED) { > if (ret < 0) { > qemu_file_set_error(f, ret); > } > diff --git a/migration/rdma.h b/migration/rdma.h > index f55f28bbed1..bb0296c3726 100644 > --- a/migration/rdma.h > +++ b/migration/rdma.h > @@ -33,7 +33,6 @@ void rdma_start_incoming_migration(InetSocketAddress *host_port, Error **errp); > #define RAM_CONTROL_ROUND 1 > #define RAM_CONTROL_FINISH 3 > > -#define RAM_SAVE_CONTROL_NOT_SUPP -1000 > #define RAM_SAVE_CONTROL_DELAYED -2000 > > #ifdef CONFIG_RDMA > @@ -56,7 +55,9 @@ static inline > int rdma_control_save_page(QEMUFile *f, ram_addr_t block_offset, > ram_addr_t offset, size_t size) > { > - return RAM_SAVE_CONTROL_NOT_SUPP; > + /* never reach */ > + assert(0); > + return -1; > } > #endif > #endif > > > > > Thanks > Zhijian > > > > >> > >>> if (!migrate_multifd() > >>> || migrate_zero_page_detection() == ZERO_PAGE_DETECTION_LEGACY) { > >>> if (save_zero_page(rs, pss, offset)) { > >>> @@ -1976,10 +1981,6 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) > >>> return ram_save_multifd_page(block, offset); > >>> } > >>> > >>> - if (control_save_page(pss, offset, &res)) { > >>> - return res; > >>> - } > >>> - > >>> return ram_save_page(rs, pss); > >>> } > >> > > -- Peter Xu