On Wed, 19 Jan 2011 10:24:09 +0900 Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > > > > This is all pretty ugly and inefficient. > > > > We call __remove_from_page_cache() which does a radix-tree lookup and > > then fiddles a bunch of accounting things. > > > > Then we immediately do the same radix-tree lookup and then undo the > > accounting changes which we just did. __And we do it in an open-coded > > fashion, thus giving the kernel yet another code site where various > > operations need to be kept in sync. > > > > Would it not be better to do a single radix_tree_lookup_slot(), > > overwrite the pointer therein and just leave all the ancilliary > > accounting unaltered? > > I agree single radix_tree_lookup but accounting still is needed since > newpage could be on another zone. What we can remove is just only > mapping->nrpages. Well. We only need to do inc/dec_zone_state if the zones are different. Perhaps the zones-equal case is worth optimising for, dunno. Also, the radix_tree_preload() should be unneeded. -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>