kvm: remove machine.mu #11570
Open
kvm: remove machine.mu #11570
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![copybara-service[bot]](https://avatars.githubusercontent.com/in/44061?s=60&v=4){kind=small}
This is only possible after cl/738486108; before that CL, vCPU handoff requires the waiter to block concurrent machine.Get() from the owner of the stolen vCPU (but this blocks *all* concurrent calls to machine.Get(), reducing utilization). - Convert machine.vCPUsByTID from map to AtomicPtrMap. - Combine vCPU.tid and vCPU.state into a single uint64 so that machine.Get() can atomically pin a VCPU to the calling thread with a single CAS. - machine.vCPUsByID is only mutated by initialization and immutable thereafter, making machine.mu unnecessary in both machine.initArchState() and machine.dropPageTables(); note in particular that addressSpace.MapFile/Unmap() => addressSpace.invalidate() => dirtySet.forEach() already reads both m.vCPUsByID slice and contents without holding machine.mu. PiperOrigin-RevId: 738547619
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
kvm: remove machine.mu
This is only possible after cl/738486108; before that CL, vCPU handoff requires
the waiter to block concurrent machine.Get() from the owner of the stolen vCPU
(but this blocks all concurrent calls to machine.Get(), reducing
utilization).
Convert machine.vCPUsByTID from map to AtomicPtrMap.
Combine vCPU.tid and vCPU.state into a single uint64 so that machine.Get()
can atomically pin a VCPU to the calling thread with a single CAS.
machine.vCPUsByID is only mutated by initialization and immutable thereafter,
making machine.mu unnecessary in both machine.initArchState() and
machine.dropPageTables(); note in particular that
addressSpace.MapFile/Unmap() => addressSpace.invalidate() =>
dirtySet.forEach() already reads both m.vCPUsByID slice and contents without
holding machine.mu.