> > mm-page_file_methods.patch > > > > This makes page_offset and others more expensive by adding a > > conditional jump to a function call that is not usually made. > > > > Why do swap pages have a different index to everyone else? > > Because the page->index of an anonymous page is related to its (anon)vma > so that it satisfies the constraints for vm_normal_page(). > > The index in the swap file it totally unrelated and quite random. Hence > the swap-cache uses page->private to store it in.
Yeah, and putting the condition into page_offset() will confuse code which uses it for finding the offset in the VMA or in a tmpfs file. So why not just have a separate page_swap_offset() function, used exclusively by swap_in/out()? Miklos -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
