ef149763a8
The drain_rcu_call() function can be blocked as long as an RCU reader stays in a read-side critical section. This is typically what happens when a TCG vCPU is executing a busy loop. It can deadlock the QEMU monitor as reported in https://gitlab.com/qemu-project/qemu/-/issues/650 . This can be avoided by allowing drain_rcu_call() to enforce an RCU grace period. Since each reader might need to do specific actions to end a read-side critical section, do it with notifiers. Prepare ground for this by adding a notifier list to the RCU reader struct and use it in wait_for_readers() if drain_rcu_call() is in progress. An API is added for readers to register their notifiers. This is largely based on a draft from Paolo Bonzini. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20211109183523.47726-2-groug@kaod.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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authz | ||
block | ||
chardev | ||
crypto | ||
disas | ||
exec | ||
fpu | ||
hw | ||
io | ||
libdecnumber | ||
migration | ||
monitor | ||
net | ||
qapi | ||
qemu | ||
qom | ||
scsi | ||
semihosting | ||
standard-headers | ||
sysemu | ||
tcg | ||
ui | ||
user | ||
elf.h | ||
glib-compat.h | ||
qemu-common.h | ||
qemu-io.h | ||
trace-tcg.h |