On Fri, Feb 07, 2014 at 10:24:45AM +0900, YAMAMOTO Takashi wrote: > > On Wed, Feb 05, 2014 at 11:47:17AM +0900, YAMAMOTO Takashi wrote: > >> > 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. > > > > Do you like the following version? > > looks good to me. thanks. > > YAMAMOTO Takashi
Thanks, applied. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
