aboutsummaryrefslogtreecommitdiff
path: root/migration
AgeCommit message (Collapse)AuthorFilesLines
2024-03-11migration/multifd: Enable multifd zero page checking by default.Hao Xiang1-1/+1
1. Set default "zero-page-detection" option to "multifd". Now zero page checking can be done in the multifd threads and this becomes the default configuration. 2. Handle migration QEMU9.0 -> QEMU8.2 compatibility. We provide backward compatibility where zero page checking is done from the migration main thread. Signed-off-by: Hao Xiang <hao.xiang@bytedance.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/20240311180015.3359271-7-hao.xiang@linux.dev Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/multifd: Implement ram_save_target_page_multifd to handle multifd ↵Hao Xiang1-9/+29
version of MigrationOps::ram_save_target_page. 1. Add a dedicated handler for MigrationOps::ram_save_target_page in multifd live migration. 2. Refactor ram_save_target_page_legacy so that the legacy and multifd handlers don't have internal functions calling into each other. Signed-off-by: Hao Xiang <hao.xiang@bytedance.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Message-Id: <20240226195654.934709-4-hao.xiang@bytedance.com> Link: https://lore.kernel.org/r/20240311180015.3359271-6-hao.xiang@linux.dev Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/multifd: Implement zero page transmission on the multifd thread.Hao Xiang8-30/+221
1. Add zero_pages field in MultiFDPacket_t. 2. Implements the zero page detection and handling on the multifd threads for non-compression, zlib and zstd compression backends. 3. Added a new value 'multifd' in ZeroPageDetection enumeration. 4. Adds zero page counters and updates multifd send/receive tracing format to track the newly added counters. Signed-off-by: Hao Xiang <hao.xiang@bytedance.com> Acked-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240311180015.3359271-5-hao.xiang@linux.dev Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/multifd: Add new migration option zero-page-detection.Hao Xiang4-0/+35
This new parameter controls where the zero page checking is running. 1. If this parameter is set to 'legacy', zero page checking is done in the migration main thread. 2. If this parameter is set to 'none', zero page checking is disabled. Signed-off-by: Hao Xiang <hao.xiang@bytedance.com> Reviewed-by: Peter Xu <peterx@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Link: https://lore.kernel.org/r/20240311180015.3359271-4-hao.xiang@linux.dev Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/multifd: Allow clearing of the file_bmap from multifdFabiano Rosas3-4/+9
We currently only need to clear the mapped-ram file bitmap from the migration thread during save_zero_page. We're about to add support for zero page detection on the multifd thread, so allow ramblock_set_file_bmap_atomic() to also clear the bits. Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240311180015.3359271-3-hao.xiang@linux.dev Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/multifd: Allow zero pages in file migrationFabiano Rosas1-1/+1
Currently, it's an error to have no data pages in the multifd file migration because zero page detection is done in the migration thread and zero pages don't reach multifd. This is enforced with the pages->num assert. We're about to add zero page detection on the multifd thread. Fix the file_write_ramblock_iov() to stop considering p->iovs_num=0 an error. Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240311180015.3359271-2-hao.xiang@linux.dev Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: purge MigrationState from public interfaceSteve Sistare1-0/+6
Move remaining MigrationState references from the public file misc.h to the private file migration.h. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-12-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: delete unused accessorsSteve Sistare1-10/+0
Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-11-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: privatize colo interfacesSteve Sistare1-6/+11
Remove private migration interfaces from net/colo-compare.c and push them to migration/colo.c. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-10-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: migration_file_set_errorSteve Sistare1-0/+11
Define and export migration_file_set_error to eliminate a dependency on MigrationState. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-9-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: migration_is_deviceSteve Sistare1-0/+7
Define and export migration_is_device to eliminate a dependency on MigrationState. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-8-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: migration_thread_is_selfSteve Sistare1-0/+7
Define and export migration_thread_is_self to eliminate a dependency on MigrationState. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-7-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: export vcpu_dirty_limit_periodSteve Sistare1-0/+7
Define and export vcpu_dirty_limit_period to eliminate a dependency on MigrationState. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-6-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: export migration_is_runningSteve Sistare4-9/+9
Delete the MigrationState parameter from migration_is_running and move it to the public API in misc.h. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-5-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: export migration_is_activeSteve Sistare1-4/+6
Delete the MigrationState parameter from migration_is_active so it can be exported and used without including migration.h. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179338-294359-4-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: export migration_is_setup_or_activeSteve Sistare3-10/+8
Delete the MigrationState parameter from migration_is_setup_or_active and move it to the public API in misc.h. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Link: https://lore.kernel.org/r/1710179338-294359-3-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: export fewer optionsSteve Sistare1-5/+1
A small number of migration options are accessed by migration clients, but to see them clients must include all of options.h, which is mostly for migration core code. migrate_mode() in particular will be needed by multiple clients. Refactor the option declarations so clients can see the necessary few via misc.h, which already exports a portion of the client API. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Link: https://lore.kernel.org/r/1710179319-294320-1-git-send-email-steven.sistare@oracle.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: Fix format in error messageAnthony PERARD1-1/+1
In file_write_ramblock_iov(), "offset" is "uintptr_t" and not "ram_addr_t". While usually they are both equivalent, this is not the case with CONFIG_XEN_BACKEND. Use the right format. This will fix build on 32-bit. Fixes: f427d90b9898 ("migration/multifd: Support outgoing mapped-ram stream format") Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Link: https://lore.kernel.org/r/20240311123439.16844-1-anthony.perard@citrix.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/rdma: Fix a memory issue for migrationYu Zhang1-1/+1
In commit 3fa9642ff7 change was made to convert the RDMA backend to accept MigrateAddress struct. However, the assignment of "host" leads to data corruption on the target host and the failure of migration. isock->host = rdma->host; By allocating the memory explicitly for it with g_strdup_printf(), the issue is fixed and the migration doesn't fail any more. Fixes: 3fa9642ff7 ("migration: convert rdma backend to accept MigrateAddress") Cc: qemu-stable <qemu-stable@nongnu.org> Cc: Li Zhijian <lizhijian@fujitsu.com> Link: https://lore.kernel.org/r/CAHEcVy4L_D6tuhJ8h=xLR4WaPaprJE3nnxZAEyUnoTrxQ6CF5w@mail.gmail.com Signed-off-by: Yu Zhang <yu.zhang@ionos.com> [peterx: use g_strdup() instead of g_strdup_printf(), per Zhijian] Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/multifd: Don't fsync when closing QIOChannelFileFabiano Rosas1-9/+19
Commit bc38feddeb ("io: fsync before closing a file channel") added a fsync/fdatasync at the closing point of the QIOChannelFile to ensure integrity of the migration stream in case of QEMU crash. The decision to do the sync at qio_channel_close() was not the best since that function runs in the main thread and the fsync can cause QEMU to hang for several minutes, depending on the migration size and disk speed. To fix the hang, remove the fsync from qio_channel_file_close(). At this moment, the migration code is the only user of the fsync and we're taking the tradeoff of not having a sync at all, leaving the responsibility to the upper layers. Fixes: bc38feddeb ("io: fsync before closing a file channel") Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240305195629.9922-1-farosas@suse.de Link: https://lore.kernel.org/r/20240305174332.2553-1-farosas@suse.de [peterx: add more comment to the qio_channel_close()] Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: Do not call PRECOPY_NOTIFY_SETUP notifiers in case of errorCédric Le Goater1-1/+5
When commit bd2270608fa0 ("migration/ram.c: add a notifier chain for precopy") added PRECOPY_NOTIFY_SETUP notifiers at the end of qemu_savevm_state_setup(), it didn't take into account a possible error in the loop calling vmstate_save() or .save_setup() handlers. Check ret value before calling the notifiers. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240304122844.1888308-10-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: Report error when shutdown failsCédric Le Goater1-1/+4
This will help detect issues regarding I/O channels usage. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240304122844.1888308-7-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration/ram: add additional checkMaksim Davydov1-0/+6
If a migration stream is broken, the address and flag reading can return zero. Thus, an irrelevant flag error will be returned instead of EIO. It can be fixed by additional check after the reading. Signed-off-by: Maksim Davydov <davydov-max@yandex-team.ru> Link: https://lore.kernel.org/r/20240304144203.158477-1-davydov-max@yandex-team.ru Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-11migration: Don't serialize devices in qemu_savevm_state_iterate()Avihai Horon1-9/+6
Commit 90697be8896c ("live migration: Serialize vmstate saving in stage 2") introduced device serialization in qemu_savevm_state_iterate(). The rationale behind it was to first complete migration of slower changing block devices and only then migrate the RAM, to avoid sending fast changing RAM pages over and over. This commit was added a long time ago, and while it was useful back then, it is not the case anymore: 1. Block migration is deprecated, see commit 66db46ca83b8 ("migration: Deprecate block migration"). 2. Today there are other iterative devices besides RAM and block, such as VFIO, which are registered for migration after RAM. With current serialization behavior, a fast changing device can block other devices from sending their data, which may prevent migration from converging in some cases. The issue described in item 2 was observed in several VFIO migration scenarios with switchover-ack capability enabled, where some workload on the VM prevented RAM from ever reaching a hard zero, thus blocking VFIO initial pre-copy data from being sent. Hence, destination could not ack switchover and migration could not converge. Fix that by not serializing iterative devices in qemu_savevm_state_iterate(). Note that this still doesn't fully prevent device starvation. As correctly pointed out by Peter [1], a fast changing device might constantly consume all allocated bandwidth and block the following devices. However, this scenario is more likely to happen only if max-bandwidth is low. [1] https://lore.kernel.org/qemu-devel/Zd6iw9dBhW6wKNxx@x1n/ Signed-off-by: Avihai Horon <avihaih@nvidia.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240304105339.20713-2-avihaih@nvidia.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-05Merge tag 'pull-qapi-2024-03-04' of https://repo.or.cz/qemu/armbru into stagingPeter Maydell1-49/+8
QAPI patches patches for 2024-03-04 # -----BEGIN PGP SIGNATURE----- # # iQJGBAABCAAwFiEENUvIs9frKmtoZ05fOHC0AOuRhlMFAmXlaSISHGFybWJydUBy # ZWRoYXQuY29tAAoJEDhwtADrkYZTdZ8P/iMgqLoAFkCCjwfkUc/rqZUezK52Ynr7 # LYwOPI/xcYD7EnVogdRgFgjWFNoivQLP5yKsU/eRTk29pwdDzTscFm/0ztTQX/Gb # ypWV+GBcu5J8mKbp1KF5w68aDD8Bat4WRfEgDQ1DV7v6CoMiUzTiF3CGXkYzqK5Y # kYNq97vdEkBFvFdOl/7scs/XXN2jG27egDhMp68RTxnPHlXZiAO9/2Bul3uVe3x0 # fzQ2ViYv0qLnjE/PwENDqqE3Thv3Sxp5iEeQQ6GWi07EVh07UtHpOM3RYyrTU0Sb # VrTApSrg0oxlkOuR0CBd9Fi+timtbokBL0DWyUpXNTfIEZfLtA9H+8riUg3EOcDp # r7a4SI/27VdPxX6Kc6zA3bi+/j1o7CLTW2LGEwuZs52nmixoo1HTWPIFdyh13g/V # QjNbun0fViHb0FVLiyDlXF/7Y+EWUWIyqwwGqbvve1DyUHQmo3CUQAKGOpkeKSBe # 4eGciVDgpBoKhtw9Kv6LCDj2cwZKC8DxBMibf7GHkOnAsX2mnyuHcey7HvYNCoF+ # yYz7oIEXdlL2eWqg7CfBZK7lniCDln50RI4Ll1v+J4r1v1kRZGMLesTYXCdNc4ku # yb4kpU4t22/RODffLE7K+fc3Onwze3fcfxlZMN66F+wFtk4KdPR2aQBE66bB8J99 # vuSKlTbT4cGL # =s9AR # -----END PGP SIGNATURE----- # gpg: Signature made Mon 04 Mar 2024 06:24:34 GMT # gpg: using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653 # gpg: issuer "armbru@redhat.com" # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full] # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" [full] # Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653 * tag 'pull-qapi-2024-03-04' of https://repo.or.cz/qemu/armbru: migration: simplify exec migration functions qapi: New strv_from_str_list() qapi: New QAPI_LIST_LENGTH() docs/devel/writing-monitor-commands: Minor improvements docs/devel/writing-monitor-commands: Repair a decade of rot qapi: Reject "Returns" section when command doesn't return anything qga/qapi-schema: Fix guest-set-memory-blocks documentation qga/qapi-schema: Tweak documentation of fsfreeze commands qga/qapi-schema: Clean up "Returns" sections qga/qapi-schema: Delete useless "Returns" sections qga/qapi-schema: Move error documentation to new "Errors" sections qapi/yank: Tweak @yank's error description for consistency qapi: Clean up "Returns" sections qapi: Delete useless "Returns" sections qapi: Move error documentation to new "Errors" sections qapi: New documentation section tag "Errors" qapi: Slightly clearer error message for invalid "Returns" section qapi: Memorize since & returns sections Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2024-03-05Merge tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu ↵Peter Maydell17-142/+1128
into staging Migartion pull request for 20240304 - Bryan's fix on multifd compression level API - Fabiano's mapped-ram series (base + multifd only) - Steve's amend on cpr document in qapi/ # -----BEGIN PGP SIGNATURE----- # # iIgEABYKADAWIQS5GE3CDMRX2s990ak7X8zN86vXBgUCZeUjKhIccGV0ZXJ4QHJl # ZGhhdC5jb20ACgkQO1/MzfOr1wbv5QD/ZexBUsmZA5qyxgGvZ2yvlUBEGNOvtmKY # kRdiYPU7khMA/0N43rn4LcqKCoq4+T+EAnYizGjIyhH/7BRUyn4DUxgO # =AeEn # -----END PGP SIGNATURE----- # gpg: Signature made Mon 04 Mar 2024 01:26:02 GMT # gpg: using EDDSA key B9184DC20CC457DACF7DD1A93B5FCCCDF3ABD706 # gpg: issuer "peterx@redhat.com" # gpg: Good signature from "Peter Xu <xzpeter@gmail.com>" [marginal] # gpg: aka "Peter Xu <peterx@redhat.com>" [marginal] # gpg: WARNING: This key is not certified with sufficiently trusted signatures! # gpg: It is not certain that the signature belongs to the owner. # Primary key fingerprint: B918 4DC2 0CC4 57DA CF7D D1A9 3B5F CCCD F3AB D706 * tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu: (27 commits) migration/multifd: Document two places for mapped-ram tests/qtest/migration: Add a multifd + mapped-ram migration test migration/multifd: Add mapped-ram support to fd: URI migration/multifd: Support incoming mapped-ram stream format migration/multifd: Support outgoing mapped-ram stream format migration/multifd: Prepare multifd sync for mapped-ram migration migration/multifd: Add incoming QIOChannelFile support migration/multifd: Add outgoing QIOChannelFile support migration/multifd: Add a wrapper for channels_created migration/multifd: Allow receiving pages without packets migration/multifd: Allow multifd without packets migration/multifd: Decouple recv method from pages migration/multifd: Rename MultiFDSend|RecvParams::data to compress_data tests/qtest/migration: Add tests for mapped-ram file-based migration migration/ram: Add incoming 'mapped-ram' migration migration/ram: Add outgoing 'mapped-ram' migration migration: Add mapped-ram URI compatibility check migration/ram: Introduce 'mapped-ram' migration capability migration/qemu-file: add utility methods for working with seekable channels io: fsync before closing a file channel ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org> # Conflicts: # migration/ram.c
2024-03-04migration: simplify exec migration functionsSteve Sistare1-49/+8
Simplify the exec migration code by using list utility functions. As a side effect, this also fixes a minor memory leak. On function return, "g_auto(GStrv) argv" frees argv and each element, which is wrong, because the function does not own the individual elements. To compensate, the code uses g_steal_pointer which NULLs argv and prevents the destructor from running, but argv is leaked. Fixes: cbab4face57b ("migration: convert exec backend ...") Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Message-ID: <20240227153321.467343-4-armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2024-03-04migration/multifd: Document two places for mapped-ramPeter Xu2-1/+19
Add two documentations for mapped-ram migration on two spots that may not be extremely clear. Reviewed-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240301091524.39900-1-peterx@redhat.com Cc: Prasad Pandit <ppandit@redhat.com> [peterx: fix two English errors per Prasad] Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Add mapped-ram support to fd: URIFabiano Rosas5-6/+64
If we receive a file descriptor that points to a regular file, there's nothing stopping us from doing multifd migration with mapped-ram to that file. Enable the fd: URI to work with multifd + mapped-ram. Note that the fds passed into multifd are duplicated because we want to avoid cross-thread effects when doing cleanup (i.e. close(fd)). The original fd doesn't need to be duplicated because monitor_get_fd() transfers ownership to the caller. Signed-off-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/20240229153017.2221-23-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Support incoming mapped-ram stream formatFabiano Rosas5-6/+73
For the incoming mapped-ram migration we need to read the ramblock headers, get the pages bitmap and send the host address of each non-zero page to the multifd channel thread for writing. Usage on HMP is: (qemu) migrate_set_capability multifd on (qemu) migrate_set_capability mapped-ram on (qemu) migrate_incoming file:migfile (the ram.h include needs to move because we've been previously relying on it being included from migration.c. Now file.h will start including multifd.h before migration.o is processed) Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-22-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Support outgoing mapped-ram stream formatFabiano Rosas7-16/+112
The new mapped-ram stream format uses a file transport and puts ram pages in the migration file at their respective offsets and can be done in parallel by using the pwritev system call which takes iovecs and an offset. Add support to enabling the new format along with multifd to make use of the threading and page handling already in place. This requires multifd to stop sending headers and leaving the stream format to the mapped-ram code. When it comes time to write the data, we need to call a version of qio_channel_write that can take an offset. Usage on HMP is: (qemu) stop (qemu) migrate_set_capability multifd on (qemu) migrate_set_capability mapped-ram on (qemu) migrate_set_parameter max-bandwidth 0 (qemu) migrate_set_parameter multifd-channels 8 (qemu) migrate file:migfile Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-21-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Prepare multifd sync for mapped-ram migrationFabiano Rosas1-7/+31
The mapped-ram migration can be performed live or non-live, but it is always asynchronous, i.e. the source machine and the destination machine are not migrating at the same time. We only need some pieces of the multifd sync operations. multifd_send_sync_main() ------------------------ Issued by the ram migration code on the migration thread, causes the multifd send channels to synchronize with the migration thread and makes the sending side emit a packet with the MULTIFD_FLUSH flag. With mapped-ram we want to maintain the sync on the sending side because that provides ordering between the rounds of dirty pages when migrating live. MULTIFD_FLUSH ------------- On the receiving side, the presence of the MULTIFD_FLUSH flag on a packet causes the receiving channels to start synchronizing with the main thread. We're not using packets with mapped-ram, so there's no MULTIFD_FLUSH flag and therefore no channel sync on the receiving side. multifd_recv_sync_main() ------------------------ Issued by the migration thread when the ram migration flag RAM_SAVE_FLAG_MULTIFD_FLUSH is received, causes the migration thread on the receiving side to start synchronizing with the recv channels. Due to compatibility, this is also issued when RAM_SAVE_FLAG_EOS is received. For mapped-ram we only need to synchronize the channels at the end of migration to avoid doing cleanup before the channels have finished their IO. Make sure the multifd syncs are only issued at the appropriate times. Note that due to pre-existing backward compatibility issues, we have the multifd_flush_after_each_section property that can cause a sync to happen at EOS. Since the EOS flag is needed on the stream, allow mapped-ram to just ignore it. Also emit an error if any other unexpected flags are found on the stream. Signed-off-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/20240229153017.2221-20-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Add incoming QIOChannelFile supportFabiano Rosas3-11/+30
On the receiving side we don't need to differentiate between main channel and threads, so whichever channel is defined first gets to be the main one. And since there are no packets, use the atomic channel count to index into the params array. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-19-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Add outgoing QIOChannelFile supportFabiano Rosas4-3/+57
Allow multifd to open file-backed channels. This will be used when enabling the mapped-ram migration stream format which expects a seekable transport. The QIOChannel read and write methods will use the preadv/pwritev versions which don't update the file offset at each call so we can reuse the fd without re-opening for every channel. Contrary to the socket migration, the file migration doesn't need an asynchronous channel creation process, so expose multifd_channel_connect() and call it directly. Note that this is just setup code and multifd cannot yet make use of the file channels. Signed-off-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/20240229153017.2221-18-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Add a wrapper for channels_createdFabiano Rosas2-1/+7
We'll need to access multifd_send_state->channels_created from outside multifd.c, so introduce a helper for that. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-17-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Allow receiving pages without packetsFabiano Rosas3-7/+138
Currently multifd does not need to have knowledge of pages on the receiving side because all the information needed is within the packets that come in the stream. We're about to add support to mapped-ram migration, which cannot use packets because it expects the ramblock section in the migration file to contain only the guest pages data. Add a data structure to transfer pages between the ram migration code and the multifd receiving threads. We don't want to reuse MultiFDPages_t for two reasons: a) multifd threads don't really need to know about the data they're receiving. b) the receiving side has to be stopped to load the pages, which means we can experiment with larger granularities than page size when transferring data. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-16-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Allow multifd without packetsFabiano Rosas1-61/+114
For the upcoming support to the new 'mapped-ram' migration stream format, we cannot use multifd packets because each write into the ramblock section in the migration file is expected to contain only the guest pages. They are written at their respective offsets relative to the ramblock section header. There is no space for the packet information and the expected gains from the new approach come partly from being able to write the pages sequentially without extraneous data in between. The new format also simply doesn't need the packets and all necessary information can be taken from the standard migration headers with some (future) changes to multifd code. Use the presence of the mapped-ram capability to decide whether to send packets. This only moves code under multifd_use_packets(), it has no effect for now as mapped-ram cannot yet be enabled with multifd. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-15-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Decouple recv method from pagesFabiano Rosas4-13/+16
Next patches will abstract the type of data being received by the channels, so do some cleanup now to remove references to pages and dependency on 'normal_num'. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-14-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Rename MultiFDSend|RecvParams::data to compress_dataFabiano Rosas3-22/+22
Use a more specific name for the compression data so we can use the generic for the multifd core code. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-13-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/ram: Add incoming 'mapped-ram' migrationFabiano Rosas1-2/+141
Add the necessary code to parse the format changes for the 'mapped-ram' capability. One of the more notable changes in behavior is that in the 'mapped-ram' case ram pages are restored in one go rather than constantly looping through the migration stream. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-11-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/ram: Add outgoing 'mapped-ram' migrationFabiano Rosas1-9/+122
Implement the outgoing migration side for the 'mapped-ram' capability. A bitmap is introduced to track which pages have been written in the migration file. Pages are written at a fixed location for every ramblock. Zero pages are ignored as they'd be zero in the destination migration as well. The migration stream is altered to put the dirty pages for a ramblock after its header instead of having a sequential stream of pages that follow the ramblock headers. Without mapped-ram (current): With mapped-ram (new): --------------------- -------------------------------- | ramblock 1 header | | ramblock 1 header | --------------------- -------------------------------- | ramblock 2 header | | ramblock 1 mapped-ram header | --------------------- -------------------------------- | ... | | padding to next 1MB boundary | --------------------- | ... | | ramblock n header | -------------------------------- --------------------- | ramblock 1 pages | | RAM_SAVE_FLAG_EOS | | ... | --------------------- -------------------------------- | stream of pages | | ramblock 2 header | | (iter 1) | -------------------------------- | ... | | ramblock 2 mapped-ram header | --------------------- -------------------------------- | RAM_SAVE_FLAG_EOS | | padding to next 1MB boundary | --------------------- | ... | | stream of pages | -------------------------------- | (iter 2) | | ramblock 2 pages | | ... | | ... | --------------------- -------------------------------- | ... | | ... | --------------------- -------------------------------- | RAM_SAVE_FLAG_EOS | -------------------------------- | ... | -------------------------------- where: - ramblock header: the generic information for a ramblock, such as idstr, used_len, etc. - ramblock mapped-ram header: the new information added by this feature: bitmap of pages written, bitmap size and offset of pages in the migration file. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-10-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration: Add mapped-ram URI compatibility checkFabiano Rosas1-0/+29
The mapped-ram migration format needs a channel that supports seeking to be able to write each page to an arbitrary offset in the migration stream. Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-9-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/ram: Introduce 'mapped-ram' migration capabilityFabiano Rosas4-0/+43
Add a new migration capability 'mapped-ram'. The core of the feature is to ensure that RAM pages are mapped directly to offsets in the resulting migration file instead of being streamed at arbitrary points. The reasons why we'd want such behavior are: - The resulting file will have a bounded size, since pages which are dirtied multiple times will always go to a fixed location in the file, rather than constantly being added to a sequential stream. This eliminates cases where a VM with, say, 1G of RAM can result in a migration file that's 10s of GBs, provided that the workload constantly redirties memory. - It paves the way to implement O_DIRECT-enabled save/restore of the migration stream as the pages are ensured to be written at aligned offsets. - It allows the usage of multifd so we can write RAM pages to the migration file in parallel. For now, enabling the capability has no effect. The next couple of patches implement the core functionality. Acked-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-8-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/qemu-file: add utility methods for working with seekable channelsFabiano Rosas2-0/+112
Add utility methods that will be needed when implementing 'mapped-ram' migration capability. Signed-off-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com> Link: https://lore.kernel.org/r/20240229153017.2221-7-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration/multifd: Cleanup multifd_recv_sync_mainFabiano Rosas2-5/+14
Some minor cleanups and documentation for multifd_recv_sync_main. Use thread_count as done in other parts of the code. Remove p->id from the multifd_recv_state sync, since that is global and not tied to a channel. Add documentation for the sync steps. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240229153017.2221-2-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01migration: Properly apply migration compression level parametersBryan Zhang1-0/+12
Some glue code was missing, so that using `qmp_migrate_set_parameters` to set `multifd-zstd-level` or `multifd-zlib-level` did not work. This commit adds the glue code to fix that. Signed-off-by: Bryan Zhang <bryan.zhang@bytedance.com> Link: https://lore.kernel.org/r/20240301035901.4006936-2-bryan.zhang@bytedance.com Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-29migration: Remove qemu_host_page_sizeRichard Henderson1-4/+18
Replace with the maximum of the real host page size and the target page size. This is an exact replacement. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Acked-by: Helge Deller <deller@gmx.de> Message-Id: <20240102015808.132373-12-richard.henderson@linaro.org>
2024-02-28migration: Use migrate_has_error() in close_return_path_on_source()Cédric Le Goater1-2/+1
close_return_path_on_source() retrieves the migration error from the the QEMUFile '->to_dst_file' to know if a shutdown is required. This shutdown is required to exit the return-path thread. Avoid relying on '->to_dst_file' and use migrate_has_error() instead. (using to_dst_file is a heuristic to infer whether rp_state.from_dst_file might be stuck on a recvmsg(). Using a generic method for detecting errors is more reliable. We also want to reduce dependency on QEMUFile::last_error) Suggested-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> [added some words about the motivation for this patch] Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240226203122.22894-3-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28migration: Join the return path thread before releasing to_dst_fileFabiano Rosas1-13/+9
The return path thread might hang at a blocking system call. Before joining the thread we might need to issue a shutdown() on the socket file descriptor to release it. To determine whether the shutdown() is necessary we look at the QEMUFile error. Make sure we only clean up the QEMUFile after the return path has been waited for. This fixes a hang when qemu_savevm_state_setup() produced an error that was detected by migration_detect_error(). That skips migration_completion() so close_return_path_on_source() would get stuck waiting for the RP thread to terminate. Reported-by: Cédric Le Goater <clg@redhat.com> Tested-by: Cédric Le Goater <clg@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240226203122.22894-2-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-28migration: Fix qmp_query_migrate mbps valueFabiano Rosas1-9/+14
The QMP command query_migrate might see incorrect throughput numbers if it runs after we've set the migration completion status but before migration_calculate_complete() has updated s->total_time and s->mbps. The migration status would show COMPLETED, but the throughput value would be the one from the last iteration and not the one from the whole migration. This will usually be a larger value due to the time period being smaller (one iteration). Move migration_calculate_complete() earlier so that the status MIGRATION_STATUS_COMPLETED is only emitted after the final counters update. Keep everything under the BQL so the QMP thread sees the updates as atomic. Rename migration_calculate_complete to migration_completion_end to reflect its new purpose of also updating s->state. Signed-off-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/20240226143335.14282-1-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
generated by cgit v1.1 at 2025-02-11 20:35:19 +0000