On 01/26/2011 07:12 PM, Anthony Liguori wrote:
What do you actually save? The longjmp() to the coroutine code, linking in to the mutex wait queue, and another switch back to the main coroutine? Given that we don't expect to block often, it seems hardly a cost worth optimizing.It's a matter of correctness, not optimization. Consider the following example: coroutine { l2 = find_l2(offset); // allocates but does not increment max cluster offset l2[l2_offset(offset)] = alloc_cluster(); co_mutex_lock(&lock); write_l2(l2); co_mutex_unlock(&lock); l1[l1_offset(offset)] = l2; co_mutex_lock(&lock); write_l1(l1); co_mutex_unlock(&lock); commit_cluster(l2[l2_offset(offset)]); } This code is incorrect.
Yes it's incorrect, but it isn't what I'm proposing. -- error compiling committee.c: too many arguments to function
