fix: avoid data race when setting memdb footprint hook #621
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/cc @sticnarf |
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How does it avoid the race? Will the read at |
Signed-off-by: ekexium <eke@fastmail.com>
ekexium
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Well I have no idea how it works :(. But the race test passes. Maybe use CAS instead? |
sticnarf
reviewed
Nov 23, 2022
internal/unionstore/memdb.go
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| db.allocator.memChangeHook = innerHook | ||
| db.vlog.memChangeHook = innerHook | ||
| atomic.CompareAndSwapPointer((*unsafe.Pointer)(unsafe.Pointer(&db.allocator.memChangeHook)), nil, unsafe.Pointer(&innerHook)) | ||
| atomic.CompareAndSwapPointer((*unsafe.Pointer)(unsafe.Pointer(&db.vlog.memChangeHook)), nil, unsafe.Pointer(&innerHook)) |
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Should we skip the second CAS if the first fails? Then, we won't assign different hooks for allocator and vlog.
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Sure we can but I think it unnecessary. By design they are always set together.
Signed-off-by: ekexium <eke@fastmail.com>
sticnarf
approved these changes
Nov 24, 2022
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