qemu-patch-raspberry4/docs
Paolo Bonzini 05e514b1d4 AioContext: optimize clearing the EventNotifier
It is pretty rare for aio_notify to actually set the EventNotifier.  It
can happen with worker threads such as thread-pool.c's, but otherwise it
should never be set thanks to the ctx->notify_me optimization.  The
previous patch, unfortunately, added an unconditional call to
event_notifier_test_and_clear; now add a userspace fast path that
avoids the call.

Note that it is not possible to do the same with event_notifier_set;
it would break, as proved (again) by the included formal model.

This patch survived over 3000 reboots on aarch64 KVM.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 1437487673-23740-7-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-07-22 12:41:40 +01:00
..
qmp
specs
aio_notify.promela
aio_notify_accept.promela AioContext: optimize clearing the EventNotifier 2015-07-22 12:41:40 +01:00
aio_notify_bug.promela
atomics.txt
bitmaps.md
blkdebug.txt
blkverify.txt
bootindex.txt
ccid.txt
ich9-ehci-uhci.cfg
image-fuzzer.txt
libcacard.txt
live-block-ops.txt
memory-hotplug.txt
memory.txt
migration.txt
multi-thread-compression.txt
multiple-iothreads.txt
multiseat.txt
pci_expander_bridge.txt
q35-chipset.cfg
qapi-code-gen.txt
qdev-device-use.txt
qemupciserial.inf
rcu.txt
rdma.txt
spice-port-fqdn.txt
tracing.txt
usb-storage.txt
usb2.txt
virtio-balloon-stats.txt
vnc-ledstate-Pseudo-encoding.txt
writing-qmp-commands.txt
xbzrle.txt
xen-save-devices-state.txt