On Wed, Feb 23, 2005 at 11:39:08AM +0000, David Howells 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. -Olof - 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/
