On Thu 12-04-18 13:58:47, Mike Kravetz wrote: > On 04/12/2018 01:40 PM, Reinette Chatre wrote: > > Hi Mike, > > > > On 2/15/2018 12:22 PM, Reinette Chatre wrote: > >> On 2/12/2018 2:20 PM, Mike Kravetz wrote: > >>> These patches came out of the "[RFC] mmap(MAP_CONTIG)" discussions at: > >>> http://lkml.kernel.org/r/21f1ec96-2822-1189-1c95-79a2bb491571@xxxxxxxxxx > >>> > >>> One suggestion in that thread was to create a friendlier interface that > >>> could be used by drivers and others outside core mm code to allocate a > >>> contiguous set of pages. The alloc_contig_range() interface is used for > >>> this purpose today by CMA and gigantic page allocation. However, this is > >>> not a general purpose interface. So, wrap alloc_contig_range() in the > >>> more general interface: > >>> > >>> struct page *find_alloc_contig_pages(unsigned int order, gfp_t gfp, int nid, > >>> nodemask_t *nodemask) > >>> > >>> No underlying changes are made to increase the likelihood that a contiguous > >>> set of pages can be found and allocated. Therefore, any user of this > >>> interface must deal with failure. The hope is that this interface will be > >>> able to satisfy some use cases today. > >> > >> As discussed in another thread a new feature, Cache Pseudo-Locking, > >> requires large contiguous regions. Until now I just exposed > >> alloc_gigantic_page() to handle these allocations in my testing. I now > >> moved to using find_alloc_contig_pages() as introduced here and all my > >> tests passed. I do hope that an API supporting large contiguous regions > >> become available. > >> > >> Thank you very much for creating this. > >> > >> Tested-by: Reinette Chatre <reinette.chatre@xxxxxxxxx> > > > > Do you still intend on submitting these changes for inclusion? > > > > I would really like to use this work but unfortunately the original > > patches submitted here do not apply anymore. I am encountering conflicts > > with, for example: > > > > commit d9cc948f6fa1c3384037f500e0acd35f03850d15 > > Author: Michal Hocko <mhocko@xxxxxxxx> > > Date: Wed Jan 31 16:20:44 2018 -0800 > > > > mm, hugetlb: integrate giga hugetlb more naturally to the allocation > > path > > > > Thank you very much > > Thanks for the reminder Reinette. > > You were the only one to comment on the original proposal. In addition, > my original use case may have gone away. So, this effort went to the > bottom of my priority list. > > I am happy rebase the patches, but would really like to get additional > comments. Allocation of hugetlbfs gigantic pages is the only existing > user. Perhaps this is a natural progression of Michal's patch above > as it moves all that special pfn range scanning out of hugetlb code. Yes, that was and still is the plan. Turn the hackish contig allocator into something more usable so I guess it would be in line with what Reinette is after. -- Michal Hocko SUSE Labs
