| Message ID | 1421938053-10318-4-git-send-email-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, 01/22 15:47, Paolo Bonzini wrote: > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > include/qemu/rcu.h | 15 ++++++++++++++- > tests/rcutorture.c | 2 ++ > 2 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h > index cfef36e..da043f2 100644 > --- a/include/qemu/rcu.h > +++ b/include/qemu/rcu.h > @@ -68,6 +68,9 @@ struct rcu_reader_data { > unsigned long ctr; > bool waiting; > > + /* Data used by reader only */ > + unsigned depth; > + > /* Data used for registry, protected by rcu_gp_lock */ > QLIST_ENTRY(rcu_reader_data) node; > }; > @@ -77,8 +80,13 @@ extern __thread struct rcu_reader_data rcu_reader; > static inline void rcu_read_lock(void) > { > struct rcu_reader_data *p_rcu_reader = &rcu_reader; > + unsigned ctr; > + > + if (p_rcu_reader->depth++ > 0) { > + return; > + } > > - unsigned ctr = atomic_read(&rcu_gp_ctr); > + ctr = atomic_read(&rcu_gp_ctr); > atomic_xchg(&p_rcu_reader->ctr, ctr); > if (atomic_read(&p_rcu_reader->waiting)) { > atomic_set(&p_rcu_reader->waiting, false); > @@ -90,6 +98,11 @@ static inline void rcu_read_unlock(void) > { > struct rcu_reader_data *p_rcu_reader = &rcu_reader; > > + assert(p_rcu_reader->depth != 0); > + if (--p_rcu_reader->depth > 0) { > + return; > + } > + > atomic_xchg(&p_rcu_reader->ctr, 0); > if (atomic_read(&p_rcu_reader->waiting)) { > atomic_set(&p_rcu_reader->waiting, false); > diff --git a/tests/rcutorture.c b/tests/rcutorture.c > index 214985f..31461c3 100644 > --- a/tests/rcutorture.c > +++ b/tests/rcutorture.c > @@ -257,9 +257,11 @@ static void *rcu_read_stress_test(void *arg) > if (p->mbtest == 0) { > n_mberror++; > } > + rcu_read_lock(); > for (i = 0; i < 100; i++) { > garbage++; > } > + rcu_read_unlock(); > pc = p->pipe_count; > rcu_read_unlock(); > if ((pc > RCU_STRESS_PIPE_LEN) || (pc < 0)) { > -- > 1.8.3.1 > > Reviewed-by: Fam Zheng <famz@redhat.com>
diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h index cfef36e..da043f2 100644 --- a/include/qemu/rcu.h +++ b/include/qemu/rcu.h @@ -68,6 +68,9 @@ struct rcu_reader_data { unsigned long ctr; bool waiting; + /* Data used by reader only */ + unsigned depth; + /* Data used for registry, protected by rcu_gp_lock */ QLIST_ENTRY(rcu_reader_data) node; }; @@ -77,8 +80,13 @@ extern __thread struct rcu_reader_data rcu_reader; static inline void rcu_read_lock(void) { struct rcu_reader_data *p_rcu_reader = &rcu_reader; + unsigned ctr; + + if (p_rcu_reader->depth++ > 0) { + return; + } - unsigned ctr = atomic_read(&rcu_gp_ctr); + ctr = atomic_read(&rcu_gp_ctr); atomic_xchg(&p_rcu_reader->ctr, ctr); if (atomic_read(&p_rcu_reader->waiting)) { atomic_set(&p_rcu_reader->waiting, false); @@ -90,6 +98,11 @@ static inline void rcu_read_unlock(void) { struct rcu_reader_data *p_rcu_reader = &rcu_reader; + assert(p_rcu_reader->depth != 0); + if (--p_rcu_reader->depth > 0) { + return; + } + atomic_xchg(&p_rcu_reader->ctr, 0); if (atomic_read(&p_rcu_reader->waiting)) { atomic_set(&p_rcu_reader->waiting, false); diff --git a/tests/rcutorture.c b/tests/rcutorture.c index 214985f..31461c3 100644 --- a/tests/rcutorture.c +++ b/tests/rcutorture.c @@ -257,9 +257,11 @@ static void *rcu_read_stress_test(void *arg) if (p->mbtest == 0) { n_mberror++; } + rcu_read_lock(); for (i = 0; i < 100; i++) { garbage++; } + rcu_read_unlock(); pc = p->pipe_count; rcu_read_unlock(); if ((pc > RCU_STRESS_PIPE_LEN) || (pc < 0)) {
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- include/qemu/rcu.h | 15 ++++++++++++++- tests/rcutorture.c | 2 ++ 2 files changed, 16 insertions(+), 1 deletion(-)