Olof Johansson <[EMAIL PROTECTED]> wrote: > > Alternately, you could just have do_page_fault() do: > > > > while (!down_read_trylock(¤t->mm->mmap_sem)) > > continue; > > > > However, note that this can suffer from starvation due to a never ending > > flow of mixed write-locks and read-locks on other CPUs. Unlikely, true, > > but not impossible. > > How can this help? > > The semaphore is held for reading by the thread that faulted in > futex_wait() -> get_user(), so no writers will be let through. Until the > writer has been let through, the down_read_trylock will never succeed > either. No forward progress can be made even with the above loop.
You're right. The "writers" would have to spin instead. David - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
