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authorMarc Mutz <marc.mutz@qt.io>2022-05-25 21:32:53 +0200
committerMarc Mutz <marc.mutz@qt.io>2022-05-26 16:43:11 +0000
commitfda8eb17417e92f8f80587937463be77899c7bed (patch)
tree8d546a021ccf3d74883b3b280eb08b08d579cca4 /config.tests/qpa/xcb-poll-for-queued-event/xcb-poll-for-queued-event.cpp
parent09c7457f4ab8021e7637e60e6c3d1f644639aec1 (diff)
Optimize QThreadPrivate::addObjectWithPendingBindingStatusChange()HEADdev
... and bindingStatus() QBindingStatus* is the final state of the value chain in m_statusOrPendingObjects, so we can use the Double-Checked Locking Pattern to avoid locking the mutex when we already have a status - it won't go away again, unlike the vector in the List state. To enable the change, make the data member an atomic<>. All loads and stores can continue to use memory_order::relaxed, except the loads of a potential status, which have to acquire, and the store of the status, which has to release. This creates the necessary synchronizes-with relation. So even though we synchronize out of middle of the mutex critical section in QThread::exec() this way, there's no data race between QThread::exec() and a potential bindingStatus() call. Change-Id: I0e0b7bd305649fa5f56a0f8723fb75f2577b90dd Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'config.tests/qpa/xcb-poll-for-queued-event/xcb-poll-for-queued-event.cpp')
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