during bulk stage of ram migration if a page is a
zero page do not send it at all.
the memory at the destination reads as zero anyway.
even if there is an madvise with QEMU_MADV_DONTNEED
at the target upon receipt of a zero page I have observed
that the target starts swapping if the memory is overcommitted.
it seems that the pages are dropped asynchronously.
this patch also updates QMP to return the number of
skipped pages in MigrationStats.
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The indirection is useless now. Backends can open s->file directly.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
With this patch, the migration_file is not needed anymore.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Rate limiting is now simply a byte counter; client call
qemu_file_rate_limit() manually to determine if they have to exit.
So it is possible and simple to move the functionality to QEMUFile.
This makes the remaining functionality of s->file redundant;
in the next patch we can remove it and write directly to s->migration_file.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This patch extracts a few small changes from the next patch, which
are unrelated to adding generic rate-limiting functionality to
QEMUFile. Make migration_set_rate_limit a simple accessor, and
use qemu_file_set_rate_limit consistently. Also fix a typo where
INT_MAX should have been SIZE_MAX.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Prepare for when s->bytes_xfer will be removed.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Second, drop the file descriptor indirection, and write directly to the
QEMUFile.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
As a start, use QEMUFile to store the destination and close it.
qemu_get_fd gets a file descriptor that will be used by the write
callbacks.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
migration_put_buffer is never called if there has been an error.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
We will go around the loop exactly once after setting last_round.
Eliminate the variable altogether.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This is consistent once that we have moved everything to migration.c
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Buffering was needed because blocking writes could take a long time
and starve other threads seeking to grab the big QEMU mutex.
Now that all writes (except within _complete callbacks) are done
outside the big QEMU mutex, we do not need buffering at all.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Only the migration_bitmap_sync() call needs the iothread lock.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This makes it possible to do blocking writes directly to the socket,
with no buffer in the middle. For RAM, only the migration_bitmap_sync()
call needs the iothread lock. For block migration, it is needed by
the block layer (including bdrv_drain_all and dirty bitmap access),
but because some code is shared between iterate and complete, all of
mig_save_device_dirty is run with the lock taken.
In the savevm case, the iterate callback runs within the big lock.
This is annoying because it complicates the rules. Luckily we do not
need to do anything about it: the RAM iterate callback does not need
the iothread lock, and block migration never runs during savevm.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Perform final cleanup in a bottom half, and add joining the thread to
the series of cleanup actions.
migrate_fd_error remains for connection error, but it doesn't need
to cleanup anything anymore.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Accessing s->state outside the big QEMU lock will simplify a bit the
locking/unlocking of the iothread lock.
We need to keep the lock in migrate_fd_error and migrate_fd_completed,
however, because they call migrate_fd_cleanup.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Completion of migration is currently done with a "nested" loop that
invokes buffered_flush: migrate_fd_completed is called by
buffered_file_thread, which calls migrate_fd_cleanup, which calls
buffered_close (via qemu_fclose), which flushes the buffer.
Simplify this, by reusing the buffered_flush call of buffered_file_thread.
Then if qemu_savevm_state_complete was called, and the buffer is empty
(including the QEMUFile buffer, for which we need the previous patch), we
are done.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Always use qemu_file_get_error to detect errors, since that is how
QEMUFile itself drops I/O after an error occurs. There is no need
to propagate and check return values all the time.
Also remove the "complete" member, since we know that it is set (via
migrate_fd_cleanup) only when the state changes.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Remove the return value of buffered_flush, pass it via the error code
of s->file. Once this is done, the error can be retrieved simply
via migrate_fd_close's call to qemu_fclose.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Including data that resided in the QEMUFile's own buffer.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The next patch will add more cases where qemu_savevm_state_cancel
needs to be called; prepare for that already, the function can be
called twice with no ill effect.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
vm_stop_force_state does:
if (runstate_is_running()) {
vm_stop(state);
} else {
runstate_set(state);
}
migration.c does:
if (runstate_is_running()) {
vm_stop(state);
} else {
vm_stop_force_state(state);
}
The code run is the same even if we always use vm_stop_force_state in
migration.c.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Unify the goto around the loop, with the exit condition at the end of it.
Both can be expressed as "while (ret >= 0)".
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
We removed the calculation in commit e4ed1541ac
Now we add it back. We need to create dirty_bytes_rate because we
can't include cpu-all.h from migration.c, and there is no other way to
include TARGET_PAGE_SIZE.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
While we are sleeping we are not sending, so we should not use that
time to estimate our bandwidth.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
0 is a very bad initial value, what we are trying to get is
max_downtime, so that is a much better estimation.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
The incoming migration is processed in a coroutine and uses an fd read
handler to enter the yielded coroutine when data becomes available.
The read handler was set too broadly, so that spurious coroutine entries
were be triggered if other coroutine users yielded (like the block
layer's bdrv_write() function).
Install the fd read only only when yielding for more data to become
available. This prevents spurious coroutine entries which break code
that assumes only a specific set of places can re-enter the coroutine.
This patch fixes crashes in block/raw-posix.c that are triggered with
"migrate -b" when qiov becomes a dangling pointer due to a spurious
coroutine entry that frees qiov early.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1360598505-5512-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
This will allow us finer control in next patches.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Now that we have error handling we can do proper handling of
buffered_flush().
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
The call in buffered_close is enough, because buffered_close is called
already by migrate_fd_cleanup.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
commit 5b4e1eb769
missed this use.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Avoid splitting the state of outgoing migration, more or less arbitrarily,
between two data structures. QEMUFileBuffered anyway is used only during
migration.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The "magic" divisions by 10 are there because of the value of BUFFER_DELAY.
Introduce a constant to explain them better.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This only moves the code (also from buffered_file.h to migration.h).
Fix whitespace until checkpatch is happy.
Signed-off-by: Juan Quintela <quintela@redhat.com>
