# By Paolo Bonzini (40) and others
# Via Juan Quintela
* quintela/migration.next: (46 commits)
  page_cache: dup memory on insert
  page_cache: fix memory leak
  Fix cache_resize to keep old entry age
  Fix page_cache leak in cache_resize
  migration: inline migrate_fd_close
  migration: eliminate s->migration_file
  migration: move contents of migration_close to migrate_fd_cleanup
  migration: move rate limiting to QEMUFile
  migration: small changes around rate-limiting
  migration: use qemu_ftell to compute bandwidth
  migration: use QEMUFile for writing outgoing migration data
  migration: use QEMUFile for migration channel lifetime
  qemu-file: simplify and export qemu_ftell
  qemu-file: add writable socket QEMUFile
  qemu-file: check exit status when closing a pipe QEMUFile
  qemu-file: fsync a writable stdio QEMUFile
  migration: merge qemu_popen_cmd with qemu_popen
  migration: use qemu_file_rate_limit consistently
  migration: remove useless qemu_file_get_error check
  migration: detect error before sleeping
  ...

A conflict was resolved the wrong way when merging commit 320ba5fe (build:
always link device_tree.o into emulators if libfdt available, 2013-02-05).
This causes a build failure for the arm-softmmu target due to multiply
defined symbol.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1362997886-9470-1-git-send-email-pbonzini@redhat.com
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

The page cache frees all data on finish, on resize and
if there is collision on insert. So it should be the caches
responsibility to dup the data that is stored in the cache.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

XBZRLE encoded migration introduced a MRU page cache
meachnism. Unfortunately, cached items where never freed in
case of a collision in the page cache on cache_insert().

This lead to out of memory conditions during XBZRLE migration
if the page cache was small and there where a lot of collisions
in the cache.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Instead of using cache_insert do the update itself
Signed-off-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Signed-off-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

The indirection is useless now.  Backends can open s->file directly.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

With this patch, the migration_file is not needed anymore.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Prepare for when s->bytes_xfer will be removed.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Second, drop the file descriptor indirection, and write directly to the
QEMUFile.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Force a flush when qemu_ftell is called.  This simplifies the buffer magic
(it also breaks qemu_ftell for input QEMUFiles, but we never use it).
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

This is what exec_close does.  Move this to the underlying QEMUFile.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

This is what fd_close does.  Prepare for switching to a QEMUFile.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

There is no reason for outgoing exec migration to do popen manually
anymore (the reason used to be that we needed the FILE* to make it
non-blocking).  Use qemu_popen_cmd.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

migration_put_buffer is never called if there has been an error.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

We will go around the loop exactly once after setting last_round.
Eliminate the variable altogether.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

This is consistent once that we have moved everything to migration.c
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Only the migration_bitmap_sync() call needs the iothread lock.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

This groups together the callbacks that later will have similar
locking rules.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Some state is shared between the block migration code and its AIO
callbacks.  Once block migration will run outside the iothread,
the block migration code and the AIO callbacks will be able to
run concurrently.  Protect the critical sections with a separate
lock.  Do the same for completed_sectors, which can be used from
the monitor.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Some small changes that will simplify the positioning of lock/unlock
primitives.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Signed-off-by: NKazuya Saito <saito.kazuya@jp.fujitsu.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan 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: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Including data that resided in the QEMUFile's own buffer.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>