On Tue, May 23, 2023 at 01:12:55PM -0400, Stefan Hajnoczi wrote:
Introduce a new API for thread-local blk_io_plug() that does not
traverse the block graph. The goal is to make blk_io_plug() multi-queue
friendly.
Instead of having block drivers track whether or not we're in a plugged
section, provide an API that allows them to defer a function call until
we're unplugged: blk_io_plug_call(fn, opaque). If blk_io_plug_call() is
called multiple times with the same fn/opaque pair, then fn() is only
called once at the end of the function - resulting in batching.
This patch introduces the API and changes blk_io_plug()/blk_io_unplug().
blk_io_plug()/blk_io_unplug() no longer require a BlockBackend argument
because the plug state is now thread-local.
Later patches convert block drivers to blk_io_plug_call() and then we
can finally remove .bdrv_co_io_plug() once all block drivers have been
converted.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
---
v2
- "is not be freed" -> "is not freed" [Eric]
---
MAINTAINERS | 1 +
include/sysemu/block-backend-io.h | 13 +--
block/block-backend.c | 22 -----
block/plug.c | 159 ++++++++++++++++++++++++++++++
hw/block/dataplane/xen-block.c | 8 +-
hw/block/virtio-blk.c | 4 +-
hw/scsi/virtio-scsi.c | 6 +-
block/meson.build | 1 +
8 files changed, 173 insertions(+), 41 deletions(-)
create mode 100644 block/plug.c
Reviewed-by: Stefano Garzarella <sgarz...@redhat.com>
