From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [patch 4/5] slub: Use __GFP_MOVABLE for slabs of HPAGE_SIZE In-Reply-To: <20080214040314.118141086@sgi.com> Message-ID: From: "Pekka Enberg" MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Date: Thu, 14 Feb 2008 09:07:04 +0200 (EET) Sender: owner-linux-mm@kvack.org Return-Path: To: clameter@sgi.com Cc: "linux-mm@kvack.org" List-ID: Hi Christoph, On 2/14/2008, "Christoph Lameter" wrote: > This is the same trick as done by the hugetlb support in the kernel. > If we allocate a huge page use __GFP_MOVABLE because an allocation > of a HUGE_PAGE size is the large allocation unit that cannot cause > fragmentation. > > This will make a system that was booted with > > slub_min_order = 9 > > not have any reclaimable slab allocations anymore. All slab allocations > will be of type MOVABLE (although they are not movable like huge pages > are also not movable). This means that we only have MOVABLE and > UNMOVABLE sections of memory which reduces the types of sections > and therefore the danger of fragmenting memory. Why does slub_min_order=9 matter? I suppose this is fixing some other real bug? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org