On Sat, 2007-11-10 at 06:43 +0100, Nick Piggin wrote: > Here's a little something to make up for the occasional extra cacheline > write in add_to_page_cache. Saves an atomic operation and 2 memory barriers > for every add_to_page_cache(). > > I suspect lockdepifying the page lock will also barf without this, too...
Yeah, I had a rather ugly trylock_page() in there. Was planning on doing something similar to this, never got round to actually doing it, thanks! > --- > Setting and clearing the page locked when inserting it into swapcache / > pagecache when it has no other references can use non-atomic page flags > operatoins because no other CPU may be operating on it at this time. > > Also, remove comments in add_to_swap_cache that suggest the contrary, and > rename it to add_to_swap_cache_lru(), better matching the filemap code, > and which meaks it more clear that the page has no other references yet. > > Also, the comments in add_to_page_cache aren't really correct. It is not > just called for new pages, but for tmpfs pages as well. They are locked > when called, so it is OK for atomic bitflag access, but we can't do > non-atomic access. Split this into add_to_page_cache_locked, for tmpfs. > > Signed-off-by: Nick Piggin <[EMAIL PROTECTED]> Reviewed-by: Peter Zijlstra <[EMAIL PROTECTED]> - 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/
