Hi, Eelco, are you missing this one?
Peng He <[email protected]> 于2022年5月26日周四 10:47写道： > ovsrcu_barrier will block the current thread until all the postponed > rcu job has been finished. it's like a OVS version of the Linux > kernel rcu_barrier(). > > Signed-off-by: Peng He <[email protected]> > Co-authored-by: Eelco Chaudron <[email protected]> > Signed-off-by: Eelco Chaudron <[email protected]> > Reviewed-by: David Marchand <[email protected]> > --- > lib/ovs-rcu.c | 37 +++++++++++++++++++++++++++++++++++++ > lib/ovs-rcu.h | 15 +++++++++++++++ > tests/library.at | 2 +- > tests/test-rcu.c | 29 +++++++++++++++++++++++++++-- > 4 files changed, 80 insertions(+), 3 deletions(-) > > diff --git a/lib/ovs-rcu.c b/lib/ovs-rcu.c > index 1866bd308..946aa04d1 100644 > --- a/lib/ovs-rcu.c > +++ b/lib/ovs-rcu.c > @@ -444,3 +444,40 @@ ovsrcu_init_module(void) > ovsthread_once_done(&once); > } > } > + > +static void > +ovsrcu_barrier_func(void *seq_) > +{ > + struct seq *seq = (struct seq *) seq_; > + seq_change(seq); > +} > + > +/* Similar to the kernel rcu_barrier, ovsrcu_barrier waits for all > outstanding > + * RCU callbacks to complete. However, unlike the kernel rcu_barrier, > which > + * might return immediately if there are no outstanding RCU callbacks, > + * this API will at least wait for a grace period. > + * > + * Another issue the caller might need to know is that the barrier is just > + * for "one-shot", i.e. if inside some RCU callbacks, another RCU > callback is > + * registered, this API only guarantees the first round of RCU callbacks > have > + * been executed after it returns. > + */ > +void > +ovsrcu_barrier(void) > +{ > + struct seq *seq = seq_create(); > + /* First let all threads flush their cbsets. */ > + ovsrcu_synchronize(); > + > + /* Then register a new cbset, ensure this cbset > + * is at the tail of the global list. */ > + uint64_t seqno = seq_read(seq); > + ovsrcu_postpone__(ovsrcu_barrier_func, (void *) seq); > + > + do { > + seq_wait(seq, seqno); > + poll_block(); > + } while (seqno == seq_read(seq)); > + > + seq_destroy(seq); > +} > diff --git a/lib/ovs-rcu.h b/lib/ovs-rcu.h > index ecc4c9201..8b397b7fb 100644 > --- a/lib/ovs-rcu.h > +++ b/lib/ovs-rcu.h > @@ -155,6 +155,19 @@ > * port_delete(id); > * } > * > + * Use ovsrcu_barrier() to wait for all the outstanding RCU callbacks to > + * finish. This is useful when you have to destroy some resources however > + * these resources are referenced in the outstanding RCU callbacks. > + * > + * void rcu_cb(void *A) { > + * do_something(A); > + * } > + * > + * void destroy_A() { > + * ovsrcu_postpone(rcu_cb, A); // will use A later > + * ovsrcu_barrier(); // wait for rcu_cb done > + * do_destroy_A(); // free A > + * } > */ > > #include "compiler.h" > @@ -310,4 +323,6 @@ void ovsrcu_synchronize(void); > > void ovsrcu_exit(void); > > +void ovsrcu_barrier(void); > + > #endif /* ovs-rcu.h */ > diff --git a/tests/library.at b/tests/library.at > index db4997d8f..6489be2c1 100644 > --- a/tests/library.at > +++ b/tests/library.at > @@ -252,7 +252,7 @@ AT_CHECK([ovstest test-barrier], [0], []) > AT_CLEANUP > > AT_SETUP([rcu]) > -AT_CHECK([ovstest test-rcu-quiesce], [0], []) > +AT_CHECK([ovstest test-rcu], [0], []) > AT_CLEANUP > > AT_SETUP([stopwatch module]) > diff --git a/tests/test-rcu.c b/tests/test-rcu.c > index 965f3c49f..bb17092bf 100644 > --- a/tests/test-rcu.c > +++ b/tests/test-rcu.c > @@ -35,7 +35,7 @@ quiescer_main(void *aux OVS_UNUSED) > } > > static void > -test_rcu_quiesce(int argc OVS_UNUSED, char *argv[] OVS_UNUSED) > +test_rcu_quiesce(void) > { > pthread_t quiescer; > > @@ -48,4 +48,29 @@ test_rcu_quiesce(int argc OVS_UNUSED, char *argv[] > OVS_UNUSED) > xpthread_join(quiescer, NULL); > } > > -OVSTEST_REGISTER("test-rcu-quiesce", test_rcu_quiesce); > +static void > +add_count(void *_count) > +{ > + unsigned *count = (unsigned *)_count; > + (*count) ++; > +} > + > +static void > +test_rcu_barrier(void) > +{ > + unsigned count = 0; > + for (int i = 0; i < 10; i ++) { > + ovsrcu_postpone(add_count, &count); > + } > + > + ovsrcu_barrier(); > + ovs_assert(count == 10); > +} > + > +static void > +test_rcu(int argc OVS_UNUSED, char *argv[] OVS_UNUSED) { > + test_rcu_quiesce(); > + test_rcu_barrier(); > +} > + > +OVSTEST_REGISTER("test-rcu", test_rcu); > -- > 2.25.1 > > -- hepeng _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
