Hi Michal, On Wednesday 06 April 2016 17:02:06 Michal Hocko wrote: > [CCing linux-mm mailing list] > > On Wed 06-04-16 13:28:37, Frank Mehnert wrote: > > Hi, > > > > Linux 4.5 introduced additional checks to ensure that compound pages are > > never marked as reserved. In our code we use PG_reserved to ensure that > > the kernel does never swap out such pages, e.g. > > Are you putting your pages on the LRU list? If not how they could get > swapped out? No, we do nothing like that. It was my understanding that at least with older kernels it was possible that pages allocated with alloc_pages() could be swapped out or otherwise manipulated, I might be wrong. For instance, it's also necessary that the physical address of the page is known and that it does never change. I know, there might be problems with automatic NUMA page migration but that's another story. > > int i; > > struct page *pages = alloc_pages(GFP_HIGHUSER | __GFP_COMP, 4); > > for (i = 0; i < 16; i++) > > > > SetPageReserved(&pages[i]); > > > > The purpose of setting PG_reserved is to prevent the kernel from swapping > > this memory out. This worked with older kernel but not with Linux 4.5 as > > setting PG_reserved to compound pages is not allowed any more. > > > > Can somebody explain how we can achieve the same result in accordance to > > the new Linux 4.5 rules? Frank -- Dr.-Ing. Frank Mehnert | Software Development Director, VirtualBox ORACLE Deutschland B.V. & Co. KG | Werkstr. 24 | 71384 Weinstadt, Germany ORACLE Deutschland B.V. & Co. KG Hauptverwaltung: Riesstraße 25, D-80992 München Registergericht: Amtsgericht München, HRA 95603 Komplementärin: ORACLE Deutschland Verwaltung B.V. Hertogswetering 163/167, 3543 AS Utrecht, Niederlande Handelsregister der Handelskammer Midden-Niederlande, Nr. 30143697 Geschäftsführer: Alexander van der Ven, Jan Schultheiss, Val Maher -- 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