On Thu, 26 Jan 2012 21:15:16 -0800 (PST) Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> wrote: > > From: Rik van Riel [mailto:riel@xxxxxxxxxx] > > Subject: Re: [PATCH] mm: implement WasActive page flag (for improving cleancache) > > > > On 01/26/2012 09:43 PM, Dan Magenheimer wrote: > > > > > Maybe the Active page bit could be overloaded with some minor > > > rewriting? IOW, perhaps the Active bit could be ignored when > > > the page is moved to the inactive LRU? (Confusing I know, but I am > > > just brainstorming...) > > > > The PG_referenced bit is already overloaded. We keep > > the bit set when we move a page from the active to the > > inactive list, so a page that was previously active > > only needs to be referenced once to become active again. > > > > The LRU bits (PG_lru, PG_active, etc) are needed to > > figure out which LRU list the page is on. I don't > > think we can overload those... > > I suspected that was true, but was just brainstorming. > Thanks for confirming. > > Are there any other page bits that are dont-care when > a page is on an LRU list? > > I'd also be interested in your/RedHat's opinion on the > 64-bit vs 32-bit market. Will RHEL7 even support 32-bit? > How about replacing PG_slab ? I think PageSlab(page) be implemented as #define SLABMAGIC (some value) #define PageSlab(page) (page->mapping == SLABMAGIC) or some... Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>