On 10/24/22 14:57, Emanuele Giuseppe Esposito wrote:
Am 23/10/2022 um 19:50 schrieb Paolo Bonzini:
On 10/22/22 17:48, Emanuele Giuseppe Esposito wrote:
+static DECLARE_RWSEM(memory_transaction);
This cannot be global, it must be per-struct kvm. Otherwise one VM can
keep the rwsem indefinitely while a second VM hangs in
KVM_KICK_ALL_RUNNING_VCPUS.
It can also be changed to an SRCU (with the down_write+up_write sequence
changed to synchronize_srcu_expedited) which has similar characteristics
to your use of the rwsem.
Makes sense, but why synchronize_srcu_expedited and not synchronize_srcu?
Because (thanks to the kick) you expect the grace period to end almost
immediately, and synchronize_srcu() will slow down sensibly the changes
to the memory map.
Paolo
