qemu/migration
Leonardo Bras 5b1d9bab2d multifd: Implement zero copy write in multifd migration (multifd-zero-copy)
Implement zero copy send on nocomp_send_write(), by making use of QIOChannel
writev + flags & flush interface.

Change multifd_send_sync_main() so flush_zero_copy() can be called
after each iteration in order to make sure all dirty pages are sent before
a new iteration is started. It will also flush at the beginning and at the
end of migration.

Also make it return -1 if flush_zero_copy() fails, in order to cancel
the migration process, and avoid resuming the guest in the target host
without receiving all current RAM.

This will work fine on RAM migration because the RAM pages are not usually freed,
and there is no problem on changing the pages content between writev_zero_copy() and
the actual sending of the buffer, because this change will dirty the page and
cause it to be re-sent on a next iteration anyway.

A lot of locked memory may be needed in order to use multifd migration
with zero-copy enabled, so disabling the feature should be necessary for
low-privileged users trying to perform multifd migrations.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220513062836.965425-9-leobras@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-05-16 13:56:24 +01:00
..
block-dirty-bitmap.c
block.c
block.h
channel.c migration: Add migrate_use_tls() helper 2022-05-16 13:56:24 +01:00
channel.h
colo-failover.c
colo.c
dirtyrate.c
dirtyrate.h
exec.c
exec.h
fd.c
fd.h
global_state.c
meson.build meson, configure: move RDMA options to meson 2022-04-28 08:52:20 +02:00
migration.c multifd: Implement zero copy write in multifd migration (multifd-zero-copy) 2022-05-16 13:56:24 +01:00
migration.h migration: Add migrate_use_tls() helper 2022-05-16 13:56:24 +01:00
multifd-zlib.c
multifd-zstd.c
multifd.c multifd: Implement zero copy write in multifd migration (multifd-zero-copy) 2022-05-16 13:56:24 +01:00
multifd.h multifd: Implement zero copy write in multifd migration (multifd-zero-copy) 2022-05-16 13:56:24 +01:00
page_cache.c
page_cache.h
postcopy-ram.c
postcopy-ram.h
qemu-file-channel.c
qemu-file-channel.h
qemu-file.c
qemu-file.h
ram.c multifd: multifd_send_sync_main now returns negative on error 2022-05-16 13:56:24 +01:00
ram.h migration: Export ram_load_postcopy() 2022-04-21 19:36:46 +01:00
rdma.c QIOChannel: Add flags on io_writev and introduce io_flush callback 2022-05-16 13:56:24 +01:00
rdma.h
savevm.c migration: Allow migrate-recover to run multiple times 2022-04-21 19:36:46 +01:00
savevm.h
socket.c multifd: Implement zero copy write in multifd migration (multifd-zero-copy) 2022-05-16 13:56:24 +01:00
socket.h
target.c
tls.c migration: fix use of TLS PSK credentials with a UNIX socket 2022-04-21 19:36:46 +01:00
tls.h
trace-events
trace.h
vmstate-types.c
vmstate.c
xbzrle.c
xbzrle.h
yank_functions.c
yank_functions.h