On Fri, Oct 20, 2006 at 01:03:24PM -0700, Zach Brown wrote: > > > I think the fake placeholder page can be a kernel-wide thing rather than > > per-dio? That would be most desirable because then we have > > > > #define PagePlaceHolder(page) (page == global_placeholder_page) > > That would be nice. The current patch hashes the page pointer with > page_waitqueue(page) to get at the zone's hashed wait queue buckets. It > would probably want to avoid that hot spot by getting at the buckets by > hashing the mapping and file offset, I guess. The page_waitqueue part only happens in the contention case. This will either be buffered vs direct io, direct io vs direct io or direct io vs truncate. I think all three should be rare enough that a single waitqueue won't hurt. It is also very hard to know the file offset without asking the radix tree, since we can't trust placeholder_page->index. -chris - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
