| Message ID | 20230420113732.336620-1-stefanha@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | block: remove aio_disable_external() API | expand |
Hi Stefan, On 20/4/23 13:37, Stefan Hajnoczi wrote: > v3: > - Resend full patch series. v2 was sent in the middle of a git rebase and was > missing patches. [Eric] > - Apply Reviewed-by tags. > Based-on: 087bc644b7634436ca9d52fe58ba9234e2bef026 (kevin/block-next) It seems kevin/block-next got rebased and doesn't contain 087bc644b76. Based on 3d1ba50c4b ("vmdk: make vmdk_is_cid_valid a coroutine_fn") I get: Applying: hw/qdev: introduce qdev_is_realized() helper Applying: virtio-scsi: avoid race between unplug and transport event Applying: virtio-scsi: stop using aio_disable_external() during unplug Applying: block/export: only acquire AioContext once for vhost_user_server_stop() error: patch failed: util/vhost-user-server.c:346 error: util/vhost-user-server.c: patch does not apply Patch failed at 0004 block/export: only acquire AioContext once for vhost_user_server_stop() Hmm patch #4 is already merged as commit 2957dc40a2, let's skip it: $ git am --skip Applying: util/vhost-user-server: rename refcount to in_flight counter Applying: block/export: wait for vhost-user-blk requests when draining Applying: block/export: stop using is_external in vhost-user-blk server Applying: hw/xen: do not use aio_set_fd_handler(is_external=true) in xen_xenstore Applying: block: add blk_in_drain() API Applying: block: drain from main loop thread in bdrv_co_yield_to_drain() Applying: xen-block: implement BlockDevOps->drained_begin() Applying: hw/xen: do not set is_external=true on evtchn fds Applying: block/export: rewrite vduse-blk drain code Applying: block/export: don't require AioContext lock around blk_exp_ref/unref() Applying: block/fuse: do not set is_external=true on FUSE fd Applying: virtio: make it possible to detach host notifier from any thread Applying: virtio-blk: implement BlockDevOps->drained_begin() Applying: virtio-scsi: implement BlockDevOps->drained_begin() Applying: virtio: do not set is_external=true on host notifiers Applying: aio: remove aio_disable_external() API error: patch failed: util/fdmon-epoll.c:131 error: util/fdmon-epoll.c: patch does not apply Patch failed at 0020 aio: remove aio_disable_external() API Now this clashes with commit e62da98527 ("aio-posix: fix race between epoll upgrade and aio_set_fd_handler()"). Indeed reverting both e62da98527 / 2957dc40a2, I can apply your series.
On Thu, Apr 20, 2023 at 03:39:59PM +0200, Philippe Mathieu-Daudé wrote: > Hi Stefan, > > On 20/4/23 13:37, Stefan Hajnoczi wrote: > > v3: > > - Resend full patch series. v2 was sent in the middle of a git rebase and was > > missing patches. [Eric] > > - Apply Reviewed-by tags. > > > Based-on: 087bc644b7634436ca9d52fe58ba9234e2bef026 (kevin/block-next) > > It seems kevin/block-next got rebased and doesn't contain 087bc644b76. > > Based on 3d1ba50c4b ("vmdk: make vmdk_is_cid_valid a coroutine_fn") > I get: > > Applying: hw/qdev: introduce qdev_is_realized() helper > Applying: virtio-scsi: avoid race between unplug and transport event > Applying: virtio-scsi: stop using aio_disable_external() during unplug > Applying: block/export: only acquire AioContext once for > vhost_user_server_stop() > error: patch failed: util/vhost-user-server.c:346 > error: util/vhost-user-server.c: patch does not apply > Patch failed at 0004 block/export: only acquire AioContext once for > vhost_user_server_stop() > > Hmm patch #4 is already merged as commit 2957dc40a2, let's skip it: > > $ git am --skip > Applying: util/vhost-user-server: rename refcount to in_flight counter > Applying: block/export: wait for vhost-user-blk requests when draining > Applying: block/export: stop using is_external in vhost-user-blk server > Applying: hw/xen: do not use aio_set_fd_handler(is_external=true) in > xen_xenstore > Applying: block: add blk_in_drain() API > Applying: block: drain from main loop thread in bdrv_co_yield_to_drain() > Applying: xen-block: implement BlockDevOps->drained_begin() > Applying: hw/xen: do not set is_external=true on evtchn fds > Applying: block/export: rewrite vduse-blk drain code > Applying: block/export: don't require AioContext lock around > blk_exp_ref/unref() > Applying: block/fuse: do not set is_external=true on FUSE fd > Applying: virtio: make it possible to detach host notifier from any thread > Applying: virtio-blk: implement BlockDevOps->drained_begin() > Applying: virtio-scsi: implement BlockDevOps->drained_begin() > Applying: virtio: do not set is_external=true on host notifiers > Applying: aio: remove aio_disable_external() API > error: patch failed: util/fdmon-epoll.c:131 > error: util/fdmon-epoll.c: patch does not apply > Patch failed at 0020 aio: remove aio_disable_external() API > > Now this clashes with commit e62da98527 ("aio-posix: fix race between epoll > upgrade and aio_set_fd_handler()"). > > Indeed reverting both e62da98527 / 2957dc40a2, I can apply your > series. Thanks, I will rebase to origin/master now to make this patch series easier to merge. Stefan
v3: - Resend full patch series. v2 was sent in the middle of a git rebase and was missing patches. [Eric] - Apply Reviewed-by tags. v2: - Do not rely on BlockBackend request queuing, implement .drained_begin/end() instead in xen-block, virtio-blk, and virtio-scsi [Paolo] - Add qdev_is_realized() API [Philippe] - Add patch to avoid AioContext lock around blk_exp_ref/unref() [Paolo] - Add patch to call .drained_begin/end() from main loop thread to simplify callback implementations The aio_disable_external() API temporarily suspends file descriptor monitoring in the event loop. The block layer uses this to prevent new I/O requests being submitted from the guest and elsewhere between bdrv_drained_begin() and bdrv_drained_end(). While the block layer still needs to prevent new I/O requests in drained sections, the aio_disable_external() API can be replaced with .drained_begin/end/poll() callbacks that have been added to BdrvChildClass and BlockDevOps. This newer .bdrained_begin/end/poll() approach is attractive because it works without specifying a specific AioContext. The block layer is moving towards multi-queue and that means multiple AioContexts may be processing I/O simultaneously. The aio_disable_external() was always somewhat hacky. It suspends all file descriptors that were registered with is_external=true, even if they have nothing to do with the BlockDriverState graph nodes that are being drained. It's better to solve a block layer problem in the block layer than to have an odd event loop API solution. The approach in this patch series is to implement BlockDevOps .drained_begin/end() callbacks that temporarily stop file descriptor handlers. This ensures that new I/O requests are not submitted in drained sections. The first two virtio-scsi patches were already sent as a separate series. I included them because they are necessary in order to fully remove aio_disable_external(). Based-on: 087bc644b7634436ca9d52fe58ba9234e2bef026 (kevin/block-next) Stefan Hajnoczi (20): hw/qdev: introduce qdev_is_realized() helper virtio-scsi: avoid race between unplug and transport event virtio-scsi: stop using aio_disable_external() during unplug block/export: only acquire AioContext once for vhost_user_server_stop() util/vhost-user-server: rename refcount to in_flight counter block/export: wait for vhost-user-blk requests when draining block/export: stop using is_external in vhost-user-blk server hw/xen: do not use aio_set_fd_handler(is_external=true) in xen_xenstore block: add blk_in_drain() API block: drain from main loop thread in bdrv_co_yield_to_drain() xen-block: implement BlockDevOps->drained_begin() hw/xen: do not set is_external=true on evtchn fds block/export: rewrite vduse-blk drain code block/export: don't require AioContext lock around blk_exp_ref/unref() block/fuse: do not set is_external=true on FUSE fd virtio: make it possible to detach host notifier from any thread virtio-blk: implement BlockDevOps->drained_begin() virtio-scsi: implement BlockDevOps->drained_begin() virtio: do not set is_external=true on host notifiers aio: remove aio_disable_external() API hw/block/dataplane/xen-block.h | 2 + include/block/aio.h | 55 --------- include/block/export.h | 2 + include/hw/qdev-core.h | 17 ++- include/hw/scsi/scsi.h | 14 +++ include/qemu/vhost-user-server.h | 8 +- include/sysemu/block-backend-common.h | 25 ++-- include/sysemu/block-backend-global-state.h | 1 + util/aio-posix.h | 1 - block.c | 7 -- block/blkio.c | 15 +-- block/block-backend.c | 7 ++ block/curl.c | 10 +- block/export/export.c | 13 +- block/export/fuse.c | 58 ++++++++- block/export/vduse-blk.c | 128 ++++++++++++++------ block/export/vhost-user-blk-server.c | 73 +++++++---- block/io.c | 5 +- block/io_uring.c | 4 +- block/iscsi.c | 3 +- block/linux-aio.c | 4 +- block/nfs.c | 5 +- block/nvme.c | 8 +- block/ssh.c | 4 +- block/win32-aio.c | 6 +- hw/block/dataplane/virtio-blk.c | 19 ++- hw/block/dataplane/xen-block.c | 42 +++++-- hw/block/virtio-blk.c | 38 +++++- hw/block/xen-block.c | 24 +++- hw/i386/kvm/xen_xenstore.c | 2 +- hw/scsi/scsi-bus.c | 46 ++++++- hw/scsi/scsi-disk.c | 28 ++++- hw/scsi/virtio-scsi-dataplane.c | 31 +++-- hw/scsi/virtio-scsi.c | 59 +++++++-- hw/virtio/virtio.c | 6 +- hw/xen/xen-bus.c | 11 +- io/channel-command.c | 6 +- io/channel-file.c | 3 +- io/channel-socket.c | 3 +- migration/rdma.c | 16 +-- tests/unit/test-aio.c | 27 +---- tests/unit/test-fdmon-epoll.c | 73 ----------- util/aio-posix.c | 20 +-- util/aio-win32.c | 8 +- util/async.c | 3 +- util/fdmon-epoll.c | 10 -- util/fdmon-io_uring.c | 8 +- util/fdmon-poll.c | 3 +- util/main-loop.c | 7 +- util/qemu-coroutine-io.c | 7 +- util/vhost-user-server.c | 38 +++--- hw/scsi/trace-events | 2 + tests/unit/meson.build | 3 - 53 files changed, 582 insertions(+), 436 deletions(-) delete mode 100644 tests/unit/test-fdmon-epoll.c