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195801d7 |
| 02-Jan-2024 |
Stefan Hajnoczi <stefanha@redhat.com> |
system/cpus: rename qemu_mutex_lock_iothread() to bql_lock()
The Big QEMU Lock (BQL) has many names and they are confusing. The actual QemuMutex variable is called qemu_global_mutex but it's commonl
system/cpus: rename qemu_mutex_lock_iothread() to bql_lock()
The Big QEMU Lock (BQL) has many names and they are confusing. The actual QemuMutex variable is called qemu_global_mutex but it's commonly referred to as the BQL in discussions and some code comments. The locking APIs, however, are called qemu_mutex_lock_iothread() and qemu_mutex_unlock_iothread().
The "iothread" name is historic and comes from when the main thread was split into into KVM vcpu threads and the "iothread" (now called the main loop thread). I have contributed to the confusion myself by introducing a separate --object iothread, a separate concept unrelated to the BQL.
The "iothread" name is no longer appropriate for the BQL. Rename the locking APIs to: - void bql_lock(void) - void bql_unlock(void) - bool bql_locked(void)
There are more APIs with "iothread" in their names. Subsequent patches will rename them. There are also comments and documentation that will be updated in later patches.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paul Durrant <paul@xen.org> Acked-by: Fabiano Rosas <farosas@suse.de> Acked-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Cédric Le Goater <clg@kaod.org> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com> Acked-by: Hyman Huang <yong.huang@smartx.com> Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com> Message-id: 20240102153529.486531-2-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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bd688fc9 |
| 11-Nov-2022 |
Emanuele Giuseppe Esposito <eesposit@redhat.com> |
accel: introduce accelerator blocker API
This API allows the accelerators to prevent vcpus from issuing new ioctls while execting a critical section marked with the accel_ioctl_inhibit_begin/end fun
accel: introduce accelerator blocker API
This API allows the accelerators to prevent vcpus from issuing new ioctls while execting a critical section marked with the accel_ioctl_inhibit_begin/end functions.
Note that all functions submitting ioctls must mark where the ioctl is being called with accel_{cpu_}ioctl_begin/end().
This API requires the caller to always hold the BQL. API documentation is in sysemu/accel-blocker.h
Internally, it uses a QemuLockCnt together with a per-CPU QemuLockCnt (to minimize cache line bouncing) to keep avoid that new ioctls run when the critical section starts, and a QemuEvent to wait that all running ioctls finish.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20221111154758.1372674-2-eesposit@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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