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path: root/block/throttle-groups.c
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2017-02-21coroutine-lock: add mutex argument to CoQueue APIsPaolo Bonzini
All that CoQueue needs in order to become thread-safe is help from an external mutex. Add this to the API. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20170213181244.16297-6-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-21block: explicitly acquire aiocontext in timers that need itPaolo Bonzini
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170213135235.12274-13-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-24throttle: Correct access to wrong BlockBackendPublic structuresAlberto Garcia
In 27ccdd52598290f0f8b58be56e235aff7aebfaf3 the throttling fields were moved from BlockDriverState to BlockBackend. However in a few cases the code started using throttling fields from the active BlockBackend instead of the round-robin token, making the algorithm behave incorrectly. This can cause starvation if there's a throttling group with several drives but only one of them has I/O. Cc: qemu-stable@nongnu.org Reported-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-05-19block: Move I/O throttling configuration functions to BlockBackendKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-05-19block: Move actual I/O throttling to BlockBackendKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-05-19block: Move throttling fields from BDS to BBKevin Wolf
This patch changes where the throttling state is stored (used to be the BlockDriverState, now it is the BlockBackend), but it doesn't actually make it a BB level feature yet. For example, throttling is still disabled when the BDS is detached from the BB. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-05-19block: Convert throttle_group_get_name() to BlockBackendKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-05-19block: throttle-groups: Use BlockBackend pointers internallyKevin Wolf
As a first step towards moving I/O throttling to the BlockBackend level, this patch changes all pointers in struct ThrottleGroup from referencing a BlockDriverState to referencing a BlockBackend. This change is valid because we made sure that throttling can only be enabled on BDSes which have a BB attached. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-05-12block: introduce bdrv_no_throttling_begin/endPaolo Bonzini
Extract the handling of throttling from bdrv_flush_io_queue. These new functions will soon become BdrvChildRole callbacks, as they can be generalized to "beginning of drain" and "end of drain". Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-05-12block: move restarting of throttled reqs to block/throttle-groups.cPaolo Bonzini
We want to remove throttled_reqs from block/io.c. This is the easy part---hide the handling of throttled_reqs during disable/enable of throttling within throttle-groups.c. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-01-20block: Clean up includesPeter Maydell
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-11-11throttle: Check for pending requests in throttle_group_unregister_bs()Alberto Garcia
throttle_group_unregister_bs() removes a BlockDriverState from its throttling group and destroys the timers. This means that there must be no pending throttled requests at that point (because it would be impossible to complete them), so the caller has to drain them first. At the moment throttle_group_unregister_bs() is only called from bdrv_io_limits_disable(), which already takes care of draining the requests, so there's nothing to worry about, but this patch makes this invariant explicit in the documentation and adds the relevant assertions. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23throttle: Remove throttle_group_lock/unlock()Alberto Garcia
The group throttling code was always meant to handle its locking internally. However, bdrv_swap() was touching the ThrottleGroup structure directly and therefore needed an API for that. Now that bdrv_swap() no longer exists there's no need for the throttle_group_lock() API anymore. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block/throttle-groups: Make incref/decref publicMax Reitz
Throttle groups are not necessarily referenced by BDSs alone; a later patch will essentially allow BBs to reference them, too. Make the ref/unref functions public so that reference can be properly accounted for. Their interface is slightly adjusted in that they return and take a ThrottleState pointer, respectively, instead of a ThrottleGroup pointer. Functionally, they are equivalent, but since ThrottleGroup is not meant to be used outside of block/throttle-groups.c, ThrottleState is easier to handle. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-06-23throttle: Check current timers before updating any_timer_armed[]Alberto Garcia
Calling throttle_group_config() cancels all timers from a particular BlockDriverState, so any_timer_armed[] should be updated accordingly. However, with the current code it may happen that a timer is armed in a different BlockDriverState from the same group, so any_timer_armed[] would be set to false in a situation where there is still a timer armed. The consequence is that we might end up with two timers armed. This should not have any noticeable impact however, since all accesses to the ThrottleGroup are protected by a lock, and the situation would become normal again shortly thereafter as soon as all timers have been fired. The correct way to solve this is to check that we're actually cancelling a timer before updating any_timer_armed[]. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 1434382875-3998-1-git-send-email-berto@igalia.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-06-12throttle: acquire the ThrottleGroup lock in bdrv_swap()Alberto Garcia
bdrv_swap() touches the fields of a BlockDriverState that are protected by the ThrottleGroup lock. Although those fields end up in their original place, they are temporarily swapped in the process, so there's a chance that an operation on a member of the same group happening on a different thread can try to use them. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: d92dc40d7c4f1fc5cda5cbbf4ffb7a4670b79d17.1433779731.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-06-12throttle: Add throttle group supportAlberto Garcia
The throttle group support use a cooperative round robin scheduling algorithm. The principles of the algorithm are simple: - Each BDS of the group is used as a token in a circular way. - The active BDS computes if a wait must be done and arms the right timer. - If a wait must be done the token timer will be armed so the token will become the next active BDS. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: f0082a86f3ac01c46170f7eafe2101a92e8fde39.1433779731.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-06-12throttle: Add throttle group infrastructureAlberto Garcia
Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 2fdb4de17210b733a13eb472c33cd08b45f8fd21.1433779731.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>