On Wed, 9 Jan 2008 13:16:42 +0900 KAMEZAWA Hiroyuki <[EMAIL PROTECTED]> wrote:
> > + > > + free = zone_page_state(zone, NR_FREE_PAGES); > > + > > + /* > > + * If we have no swap space, do not bother scanning anon pages > > + */ > > + if (nr_swap_pages <= 0) > > + percent[0] = 0; > Doesn't this mean that swap-cache in ACTIVE_ANON_LIST is not scanned ? > Or swap-cache is in File-Cache list ? You are right, the swap cache will not be scanned once we run completely out of swap space. To compensate for that, this patch series has a patch that does scanning of swap cache and freeing of swap space used by pages on the LRU list while there is still space free. Scanning all of the anon LRU lists could be a lot of work for very little gain. A typical large server will have 32GB or more of RAM, but only the default 2GB of swap. All we accomplish by scanning the anonymous memory on a system like that (once swap is full) is eating up CPU time and causing lock contention. -- All rights reversed. -- 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/
