> On Wed, Jan 15, 2014 at 12:41:20PM +0900, YAMAMOTO Takashi wrote: >> Add a comment about implicit synchronization which >> fat-rwlock seems to rely on. >> >> Signed-off-by: YAMAMOTO Takashi <yamam...@valinux.co.jp> >> --- >> lib/ovs-thread.h | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/lib/ovs-thread.h b/lib/ovs-thread.h >> index 8cf2ecc..dab7510 100644 >> --- a/lib/ovs-thread.h >> +++ b/lib/ovs-thread.h >> @@ -447,6 +447,14 @@ void xpthread_join(pthread_t, void **); >> * Compared to pthread_key_t, ovsthread_key_t has the follow limitations: >> * >> * - Destructors must not access thread-specific data (via >> ovsthread_key). >> + * >> + * Unlike pthread_key_t, this API implicitly serializes key removal >> + * (ovsthread_key_delete) and thread exit. (destructor) >> + * I.e. >> + * - ovsthread_key_delete ensures the completion of destructors for >> + * the key. >> + * - Once ovsthread_key_delete completed, no destructors for the key >> + * will be executed on thread exit. >> */ >> typedef struct ovsthread_key *ovsthread_key_t; > > I think I understand what you are saying, but I think that I would > phrase it differently. Does the following express what you mean? > > diff --git a/lib/ovs-thread.c b/lib/ovs-thread.c > index a20b2fd..18e524e 100644 > --- a/lib/ovs-thread.c > +++ b/lib/ovs-thread.c > @@ -592,7 +592,8 @@ ovsthread_key_create(ovsthread_key_t *keyp, void > (*destructor)(void *)) > } > > /* Frees 'key'. The destructor supplied to ovsthread_key_create(), if any, > is > - * not called. > + * not called. This function returns only after any running destructors for > + * 'key' complete execution.
'running destructors' is not exact. i believe pthread api allows for concurrent exiting threads to start executing the destructor after pthread_key_delete completed. but this ovsthread one doesn't. and fat-rwlock relies on it. i think it's better to say the difference explicitly as it guarantees more than pthread while using similar-looking names. i was confused when reading fat-rwlock. YAMAMOTO Takashi > * > * This function is similar to xpthread_key_delete(). */ > void > > _______________________________________________ > dev mailing list > dev@openvswitch.org > http://openvswitch.org/mailman/listinfo/dev _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
