Commit Graph

113 Commits

Author SHA1 Message Date
Peter Xu
05b7ec1890 migration/multifd: Rename p->num_packets and clean it up
This field, no matter whether on src or dest, is only used for debugging
purpose.

They can even be removed already, unless it still more or less provide some
accounting on "how many packets are sent/recved for this thread".  The
other more important one is called packet_num, which is embeded in the
multifd packet headers (MultiFDPacket_t).

So let's keep them for now, but make them much easier to understand, by
doing below:

  - Rename both of them to packets_sent / packets_recved, the old
  name (num_packets) are waaay too confusing when we already have
  MultiFDPacket_t.packets_num.

  - Avoid worrying on the "initial packet": we know we will send it, that's
  good enough.  The accounting won't matter a great deal to start with 0 or
  with 1.

  - Move them to where we send/recv the packets.  They're:

    - multifd_send_fill_packet() for senders.
    - multifd_recv_unfill_packet() for receivers.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-10-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
83c560fb42 migration/multifd: Drop pages->num check in sender thread
Now with a split SYNC handler, we always have pages->num set for
pending_job==true.  Assert it instead.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-9-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
e3cce9af10 migration/multifd: Simplify locking in sender thread
The sender thread will yield the p->mutex before IO starts, trying to not
block the requester thread.  This may be unnecessary lock optimizations,
because the requester can already read pending_job safely even without the
lock, because the requester is currently the only one who can assign a
task.

Drop that lock complication on both sides:

  (1) in the sender thread, always take the mutex until job done
  (2) in the requester thread, check pending_job clear lockless

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-8-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
f5f48a7891 migration/multifd: Separate SYNC request with normal jobs
Multifd provide a threaded model for processing jobs.  On sender side,
there can be two kinds of job: (1) a list of pages to send, or (2) a sync
request.

The sync request is a very special kind of job.  It never contains a page
array, but only a multifd packet telling the dest side to synchronize with
sent pages.

Before this patch, both requests use the pending_job field, no matter what
the request is, it will boost pending_job, while multifd sender thread will
decrement it after it finishes one job.

However this should be racy, because SYNC is special in that it needs to
set p->flags with MULTIFD_FLAG_SYNC, showing that this is a sync request.
Consider a sequence of operations where:

  - migration thread enqueue a job to send some pages, pending_job++ (0->1)

  - [...before the selected multifd sender thread wakes up...]

  - migration thread enqueue another job to sync, pending_job++ (1->2),
    setup p->flags=MULTIFD_FLAG_SYNC

  - multifd sender thread wakes up, found pending_job==2
    - send the 1st packet with MULTIFD_FLAG_SYNC and list of pages
    - send the 2nd packet with flags==0 and no pages

This is not expected, because MULTIFD_FLAG_SYNC should hopefully be done
after all the pages are received.  Meanwhile, the 2nd packet will be
completely useless, which contains zero information.

I didn't verify above, but I think this issue is still benign in that at
least on the recv side we always receive pages before handling
MULTIFD_FLAG_SYNC.  However that's not always guaranteed and just tricky.

One other reason I want to separate it is using p->flags to communicate
between the two threads is also not clearly defined, it's very hard to read
and understand why accessing p->flags is always safe; see the current impl
of multifd_send_thread() where we tried to cache only p->flags.  It doesn't
need to be that complicated.

This patch introduces pending_sync, a separate flag just to show that the
requester needs a sync.  Alongside, we remove the tricky caching of
p->flags now because after this patch p->flags should only be used by
multifd sender thread now, which will be crystal clear.  So it is always
thread safe to access p->flags.

With that, we can also safely convert the pending_job into a boolean,
because we don't support >1 pending jobs anyway.

Always use atomic ops to access both flags to make sure no cache effect.
When at it, drop the initial setting of "pending_job = 0" because it's
always allocated using g_new0().

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-7-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
efd8c5439d migration/multifd: Drop MultiFDSendParams.normal[] array
This array is redundant when p->pages exists.  Now we extended the life of
p->pages to the whole period where pending_job is set, it should be safe to
always use p->pages->offset[] rather than p->normal[].  Drop the array.

Alongside, the normal_num is also redundant, which is the same to
p->pages->num.

This doesn't apply to recv side, because there's no extra buffering on recv
side, so p->normal[] array is still needed.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
836eca47f6 migration/multifd: Postpone reset of MultiFDPages_t
Now we reset MultiFDPages_t object in the multifd sender thread in the
middle of the sending job.  That's not necessary, because the "*pages"
struct will not be reused anyway until pending_job is cleared.

Move that to the end after the job is completed, provide a helper to reset
a "*pages" object.  Use that same helper when free the object too.

This prepares us to keep using p->pages in the follow up patches, where we
may drop p->normal[].

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-5-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
15f3f21d59 migration/multifd: Drop MultiFDSendParams.quit, cleanup error paths
Multifd send side has two fields to indicate error quits:

  - MultiFDSendParams.quit
  - &multifd_send_state->exiting

Merge them into the global one.  The replacement is done by changing all
p->quit checks into the global var check.  The global check doesn't need
any lock.

A few more things done on top of this altogether:

  - multifd_send_terminate_threads()

    Moving the xchg() of &multifd_send_state->exiting upper, so as to cover
    the tracepoint, migrate_set_error() and migrate_set_state().

  - multifd_send_sync_main()

    In the 2nd loop, add one more check over the global var to make sure we
    don't keep the looping if QEMU already decided to quit.

  - multifd_tls_outgoing_handshake()

    Use multifd_send_terminate_threads() to set the error state.  That has
    a benefit of updating MigrationState.error to that error too, so we can
    persist that 1st error we hit in that specific channel.

  - multifd_new_send_channel_async()

    Take similar approach like above, drop the migrate_set_error() because
    multifd_send_terminate_threads() already covers that.  Unwrap the helper
    multifd_new_send_channel_cleanup() along the way; not really needed.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
48c0f5d56f migration/multifd: multifd_send_kick_main()
When a multifd sender thread hit errors, it always needs to kick the main
thread by kicking all the semaphores that it can be waiting upon.

Provide a helper for it and deduplicate the code.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Peter Xu
8888a552bf migration/multifd: Drop stale comment for multifd zero copy
We've already done that with multifd_flush_after_each_section, for multifd
in general.  Drop the stale "TODO-like" comment.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00
Fabiano Rosas
6074f81625 migration/multifd: Change multifd_pages_init argument
The 'size' argument is actually the number of pages that fit in a
multifd packet. Change it to uint32_t and rename.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240104142144.9680-4-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-16 11:16:09 +08:00
Fabiano Rosas
9346fa1870 migration/multifd: Remove QEMUFile from where it is not needed
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240104142144.9680-3-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-16 11:16:09 +08:00
Fabiano Rosas
dca1bc7f24 migration/multifd: Remove MultiFDPages_t::packet_num
This was introduced by commit 34c55a94b1 ("migration: Create multipage
support") and never used.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240104142144.9680-2-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-16 11:16:09 +08:00
Avihai Horon
3fc58efa93 migration/multifd: Remove unnecessary usage of local Error
According to Error API, usage of ERRP_GUARD() or a local Error instead
of errp is needed if errp is passed to void functions, where it is later
dereferenced to see if an error occurred.

There are several places in multifd.c that use local Error although it
is not needed. Change these places to use errp directly.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20231231093016.14204-12-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-04 09:52:42 +08:00
Avihai Horon
6ae208ce96 migration/multifd: Fix leaking of Error in TLS error flow
If there is an error in multifd TLS handshake task,
multifd_tls_outgoing_handshake() retrieves the error with
qio_task_propagate_error() but never frees it.

Fix it by freeing the obtained Error.

In addition, the error is not reported at all, so report it with
migrate_set_error().

Fixes: 2964714015 ("migration/tls: add support for multifd tls-handshake")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20231231093016.14204-8-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-04 09:52:42 +08:00
Avihai Horon
a4395f5d3c migration/multifd: Simplify multifd_channel_connect() if else statement
The else branch in multifd_channel_connect() is redundant because when
the if branch is taken the function returns.

Simplify the code by removing the else branch.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20231231093016.14204-7-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-04 09:52:42 +08:00
Avihai Horon
c77b40859a migration/multifd: Fix error message in multifd_recv_initial_packet()
In multifd_recv_initial_packet(), if MultiFDInit_t->id is greater than
the configured number of multifd channels, an irrelevant error message
about multifd version is printed.

Change the error message to a relevant one about the channel id.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20231231093016.14204-6-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-04 09:52:42 +08:00
Fabiano Rosas
0a08c7947b migration/multifd: Stop setting p->ioc before connecting
This is being shadowed but the assignments at
multifd_channel_connect() and multifd_tls_channel_connect() .

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Message-ID: <20231110200241.20679-2-farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-11-30 09:50:10 +01:00
Juan Quintela
0f8596180a migration: Remove transferred atomic counter
After last commit, it is a write only variable.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-12-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Fabiano Rosas
175e63c982 migration/multifd: Stop checking p->quit in multifd_send_thread
We don't need to check p->quit in the multifd_send_thread() because it
is shadowed by the 'exiting' flag. Ever since that flag was added
p->quit became obsolete as a way to stop the thread.

Since p->quit is set at multifd_send_terminate_threads() under the
p->mutex lock, the thread will only see it once it loops, so 'exiting'
will always be seen first.

Note that setting p->quit at multifd_send_terminate_threads() still
makes sense because we need a way to inform multifd_send_pages() that
the channel has stopped.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012140651.13122-3-farosas@suse.de>
2023-10-20 08:51:41 +02:00
Fabiano Rosas
967e388987 migration/multifd: Clarify Error usage in multifd_channel_connect
The function is currently called from two sites, one always gives it a
NULL Error and the other always gives it a non-NULL Error.

In the non-NULL case, all it does it trace the error and return. One
of the callers already have tracing, add a tracepoint to the other and
stop passing the error into the function.

Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012134343.23757-4-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
ee8a7c9c46 migration/multifd: Unify multifd_send_thread error paths
The preferred usage of the Error type is to always set both the return
code and the error when a failure happens. As all code called from the
send thread follows this pattern, we'll always have the return code
and the error set at the same time.

Aside from the convention, in this piece of code this must be the
case, otherwise the if (ret != 0) would be exiting the thread without
calling multifd_send_terminate_threads() which is incorrect.

Unify both paths to make it clear that both are taken when there's an
error.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012134343.23757-3-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
0e92f64448 migration/multifd: Remove direct "socket" references
We're about to enable support for other transports in multifd, so
remove direct references to sockets.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012134343.23757-2-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Elena Ufimtseva
1618f55221 multifd: reset next_packet_len after sending pages
Sometimes multifd sends just sync packet with no pages
(normal_num is 0). In this case the old value is being
preserved and being accounted for while only packet_len
is being transferred.
Reset it to 0 after sending and accounting for.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184358.97349-5-elena.ufimtseva@oracle.com>
2023-10-17 09:25:13 +02:00
Elena Ufimtseva
68b6e00048 multifd: fix counters in multifd_send_thread
Previous commit cbec7eb768
"migration/multifd: Compute transferred bytes correctly"
removed accounting for packet_len in non-rdma
case, but the next_packet_size only accounts for pages, not for
the header packet (normal_pages * PAGE_SIZE) that is being sent
as iov[0]. The packet_len part should be added to account for
the size of MultiFDPacket and the array of the offsets.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184358.97349-4-elena.ufimtseva@oracle.com>
2023-10-17 09:25:13 +02:00
Fabiano Rosas
788fa68041 migration/multifd: Rename threadinfo.c functions
We're about to add more functions to this file so make it use the same
coding style as the rest of the code.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20230607161306.31425-2-farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Michael Tokarev
d8b71d96b3 migration: spelling fixes
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
2023-07-25 17:13:20 +03:00
Philippe Mathieu-Daudé
7d5b0d6864 bulk: Remove pointless QOM casts
Mechanical change running Coccinelle spatch with content
generated from the qom-cast-macro-clean-cocci-gen.py added
in the previous commit.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230601093452.38972-3-philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2023-06-05 20:48:34 +02:00
Juan Quintela
cbec7eb768 migration/multifd: Compute transferred bytes correctly
In the past, we had to put the in the main thread all the operations
related with sizes due to qemu_file not beeing thread safe.  As now
all counters are atomic, we can update the counters just after the
do the write.  As an aditional bonus, we are able to use the right
value for the compression methods.  Right now we were assuming that
there were no compression at all.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20230515195709.63843-17-quintela@redhat.com>
2023-05-18 18:41:46 +02:00
Juan Quintela
bd7ceaf6d5 migration: We don't need the field rate_limit_used anymore
Since previous commit, we calculate how much data we have send with
migration_transferred_bytes() so no need to maintain this counter and
remember to always update it.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20230515195709.63843-10-quintela@redhat.com>
2023-05-18 18:40:51 +02:00
Juan Quintela
e1fde0e038 migration: Move rate_limit_max and rate_limit_used to migration_stats
These way we can make them atomic and use this functions from any
place.  I also moved all functions that use rate_limit to
migration-stats.

Functions got renamed, they are not qemu_file anymore.

qemu_file_rate_limit -> migration_rate_exceeded
qemu_file_set_rate_limit -> migration_rate_set
qemu_file_get_rate_limit -> migration_rate_get
qemu_file_reset_rate_limit -> migration_rate_reset
qemu_file_acct_rate_limit -> migration_rate_account.

Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-6-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-18 18:40:51 +02:00
Lukas Straub
5d1d1fcf43 multifd: Add the ramblock to MultiFDRecvParams
This will be used in the next commits to add colo support to multifd.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <88135197411df1a71d7832962b39abf60faf0021.1683572883.git.lukasstraub2@web.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-10 18:48:11 +02:00
Juan Quintela
0deb7e9b6c migration: Drop unused parameter for migration_tls_client_create()
It is not needed since we moved the accessor for tls properties to
options.c.

Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2023-05-03 11:24:20 +02:00
Juan Quintela
aff3f6606d migration: Rename ram_counters to mig_stats
migration_stats is just too long, and it is going to have more than
ram counters in the near future.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
2023-05-03 11:24:20 +02:00
Juan Quintela
947701cc1a migration: Move ram_stats to its own file migration-stats.[ch]
There is already include/qemu/stats.h, so stats.h was a bad idea.
We want this file to not depend on anything else, we will move all the
migration counters/stats to this struct.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
2023-05-03 11:24:19 +02:00
Juan Quintela
e232199aad multifd: We already account for this packet on the multifd thread
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
2023-05-03 11:24:19 +02:00
Juan Quintela
d2026ee117 multifd: Fix the number of channels ready
We don't wait in the sem when we are doing a sync_main.  Make it wait
there.  To make things clearer, we mark the channel ready at the
begining of the thread loop.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
2023-04-27 16:37:28 +02:00
Juan Quintela
b4bc342c76 migration: Move migrate_use_zero_copy_send() to options.c
Once that we are there, we rename the function to
migrate_zero_copy_send() to be consistent with all other capabilities.

We can remove the CONFIG_LINUX guard.  We already check that we can't
setup this capability in migrate_caps_check().

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2023-04-24 15:01:46 +02:00
Juan Quintela
51b07548f7 migration: Move migrate_use_multifd() to options.c
Once that we are there, we rename the function to migrate_multifd()
to be consistent with all other capabilities.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2023-04-24 15:01:46 +02:00
Juan Quintela
4291823694 migration: Make dirty_sync_missed_zero_copy atomic
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
2023-04-24 11:28:57 +02:00
Juan Quintela
cf671116fa migration: Make multifd_bytes atomic
In the spirit of:

commit 394d323bc3451e4d07f13341cb8817fac8dfbadd
Author: Peter Xu <peterx@redhat.com>
Date:   Tue Oct 11 17:55:51 2022 -0400

    migration: Use atomic ops properly for page accountings

Reviewed-by: David Edmondson <david.edmondson@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-04-24 11:28:57 +02:00
Juan Quintela
30fb22cda4 migration: Update atomic stats out of the mutex
Reviewed-by: David Edmondson <david.edmondson@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-04-24 11:28:56 +02:00
Juan Quintela
abce5fa16d migration: Merge ram_counters and ram_atomic_counters
Using MgrationStats as type for ram_counters mean that we didn't have
to re-declare each value in another struct. The need of atomic
counters have make us to create MigrationAtomicStats for this atomic
counters.

Create RAMStats type which is a merge of MigrationStats and
MigrationAtomicStats removing unused members.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>

---

Fix typos found by David Edmondson
2023-04-24 11:28:56 +02:00
Wei Wang
ff1585d1d8 migration/multifd: correct multifd_send_thread to trace the flags
The p->flags could be updated via the send_prepare callback, e.g. OR-ed
with MULTIFD_FLAG_ZLIB via zlib_send_prepare. Assign p->flags to the
local "flags" before the send_prepare callback could only get partial of
p->flags. Fix it by moving the assignment of p->flags to the local flags
after the callback, so that the correct flags can be traced.

Fixes: ab7cbb0b9a ("multifd: Make no compression operations into its own structure")
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-03-16 16:07:07 +01:00
Leonardo Bras
cfc3bcf373 migration/multifd: Move load_cleanup inside incoming_state_destroy
Currently running migration_incoming_state_destroy() without first running
multifd_load_cleanup() will cause a yank error:

qemu-system-x86_64: ../util/yank.c:107: yank_unregister_instance:
Assertion `QLIST_EMPTY(&entry->yankfns)' failed.
(core dumped)

The above error happens in the target host, when multifd is being used
for precopy, and then postcopy is triggered and the migration finishes.
This will crash the VM in the target host.

To avoid that, move multifd_load_cleanup() inside
migration_incoming_state_destroy(), so that the load cleanup becomes part
of the incoming state destroying process.

Running multifd_load_cleanup() twice can become an issue, though, but the
only scenario it could be ran twice is on process_incoming_migration_bh().
So removing this extra call is necessary.

On the other hand, this multifd_load_cleanup() call happens way before the
migration_incoming_state_destroy() and having this happening before
dirty_bitmap_mig_before_vm_start() and vm_start() may be a need.

So introduce a new function multifd_load_shutdown() that will mainly stop
all multifd threads and close their QIOChannels. Then use this function
instead of multifd_load_cleanup() to make sure nothing else is received
before dirty_bitmap_mig_before_vm_start().

Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13 03:45:40 +01:00
Leonardo Bras
10351fbad1 migration/multifd: Join all multifd threads in order to avoid leaks
Current approach will only join threads that are still running.

For the threads not joined, resources or private memory are always kept in
the process space and never reclaimed before process end, and this risks
serious memory leaks.

This should usually not represent a big problem, since multifd migration
is usually just ran at most a few times, and after it succeeds there is
not much to be done before exiting the process.

Yet still, it should not hurt performance to join all of them.

Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13 03:45:34 +01:00
Leonardo Bras
d926f3bb2a migration/multifd: Remove unnecessary assignment on multifd_load_cleanup()
Before assigning "p->quit = true" for every multifd channel,
multifd_load_cleanup() will call multifd_recv_terminate_threads() which
already does the same assignment, while protected by a mutex.

So there is no point doing the same assignment again.

Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13 03:45:28 +01:00
Leonardo Bras
e5bac1f525 migration/multifd: Change multifd_load_cleanup() signature and usage
Since it's introduction in commit f986c3d256 ("migration: Create multifd
migration threads"), multifd_load_cleanup() never returned any value
different than 0, neither set up any error on errp.

Even though, on process_incoming_migration_bh() an if clause uses it's
return value to decide on setting autostart = false, which will never
happen.

In order to simplify the codebase, change multifd_load_cleanup() signature
to 'void multifd_load_cleanup(void)', and for every usage remove error
handling or decision made based on return value != 0.

Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-13 03:44:44 +01:00
Peter Xu
d6f74fd12e migration: Rework multi-channel checks on URI
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".

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11 16:51:09 +01:00
Li Zhang
bca762c2b9 multifd: Remove some redundant code
Clean up some unnecessary code

Signed-off-by: Li Zhang <lizhang@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11 16:51:09 +01:00
Li Zhang
e3f37b2ce6 multifd: cleanup the function multifd_channel_connect
Cleanup multifd_channel_connect

Signed-off-by: Li Zhang <lizhang@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-11 16:51:09 +01:00