On Thu, 20 May 2010, Nick Piggin wrote: > > Well I mean a full invalidate -- invalidate_mapping_pages -- so there is > literally no pagecache there at all. Umm. That won't work. Think mapped pages. You can't handle them atomically, so somebody will page-fault them in. So you'd have to have a "invalidate_and_replace()" to do it atomically while holding the mapping spinlock or something. And WHAT IS THE POINT? That will be about a million times slower than just doing the effing copy in the first place! Memory copies are _not_ slow. Not compared to taking locks and doing TLB invalidates. Linus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>