Subject: Re: [PATCH 29/33] autonuma: page_autonuma Reply-To: In-Reply-To: <0000013a2c223da2-632aa43e-21f8-4abd-a0ba-2e1b49881e3a-000000@xxxxxxxxxxxxxxxxxxx> Hi Christoph, On Thu, Oct 04, 2012 at 02:16:14PM +0000, Christoph Lameter wrote: > On Thu, 4 Oct 2012, Andrea Arcangeli wrote: > > > Move the autonuma_last_nid from the "struct page" to a separate > > page_autonuma data structure allocated in the memsection (with > > sparsemem) or in the pgdat (with flatmem). > > Note that there is a available word in struct page before the autonuma > patches on x86_64 with CONFIG_HAVE_ALIGNED_STRUCT_PAGE. > > In fact the page_autonuma fills up the structure to nicely fit in one 64 > byte cacheline. Good point indeed. So we could drop page_autonuma by creating a CONFIG_SLUB=y dependency (AUTONUMA wouldn't be available in the kernel config if SLAB=y, and it also wouldn't be available on 32bit archs but the latter isn't a problem). I think it's a reasonable alternative to page_autonuma. Certainly it looks more appealing than taking over 16 precious bits from page->flags. There are still pros and cons. I'm neutral on it so more comments would be welcome ;). Andrea PS. randomly moved some in Cc over to Bcc as I overflowed the max header allowed on linux-kernel oops! -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>