afbe70535f
This function will be used to avoid recursive locking of the iothread lock whenever address_space_rw/ld*/st* are called with the BQL held, which is almost always the case. Tracking whether the iothread is owned is very cheap (just use a TLS variable) but requires some care because now the lock must always be taken with qemu_mutex_lock_iothread(). Previously this wasn't the case. Outside TCG mode this is not a problem. In TCG mode, we need to be careful and avoid the "prod out of compiled code" step if already in a VCPU thread. This is easily done with a check on current_cpu, i.e. qemu_in_vcpu_thread(). Hopefully, multithreaded TCG will get rid of the whole logic to kick VCPUs whenever an I/O event occurs! Cc: Frederic Konrad <fred.konrad@greensocs.com> Message-Id: <1434646046-27150-3-git-send-email-pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
16 lines
197 B
C
16 lines
197 B
C
#include "qemu-common.h"
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#include "qemu/main-loop.h"
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bool qemu_mutex_iothread_locked(void)
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{
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return true;
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}
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void qemu_mutex_lock_iothread(void)
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{
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}
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void qemu_mutex_unlock_iothread(void)
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{
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}
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