From mboxrd@z Thu Jan 1 00:00:00 1970 From: jbarnes@sgi.com (Jesse Barnes) Date: Mon, 10 Nov 2003 19:08:31 +0000 Subject: Re: discontig patch question Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Mon, Nov 10, 2003 at 12:34:47PM -0600, Van Maren, Kevin wrote: > > Yeah, but 1UL< > Only if MAX_ORDER >= PAGE_SHIFT. > > But page alignment isn't the question: it is already aligned to > the 16MB or 64MB granules. Right. Spaced out there for a minute... > But you are saying that the address doesn't have to be as strict: > even if allocating 2^MAX_ORDER _pages_, the start doesn't have to > be aligned at a natural (PAGE_SIZE< we can change the ORDERROUNDDOWN to not be as aggressive. Well, strictly speaking I don't think start _has_ to align on those conditions, but the hugetlb stuff may that it does (I haven't looked). > But then it also makes sense to have a smaller MAX_ORDER when not > using 4GB hugepages? I'm happy with <= 256MB hugepages with 16GB ram, > so I guess I'd rather MAX_ORDER was normally smaller, and increased > only with very large hugepage pages. That makes sense to me. It seems like FORCE_MAX_ZONEORDER should depend on HUGETLB_PAGE_SIZE_* so that we don't apply unnecessary alignment constraints. Of course, there's probably something I'm missing, Rohit might know more. Jesse