On Fri 17-07-20 16:46:38, Joonsoo Kim wrote: > 2020년 7월 15일 (수) 오후 5:24, Michal Hocko <[email protected]>님이 작성: > > > > On Wed 15-07-20 14:05:27, Joonsoo Kim wrote: > > > From: Joonsoo Kim <[email protected]> > > > > > > We have well defined scope API to exclude CMA region. > > > Use it rather than manipulating gfp_mask manually. With this change, > > > we can now use __GFP_MOVABLE for gfp_mask and the ZONE_MOVABLE is also > > > searched by page allocator. For hugetlb, gfp_mask is redefined since > > > it has a regular allocation mask filter for migration target. > > > > > > Note that this can be considered as a fix for the commit 9a4e9f3b2d73 > > > ("mm: update get_user_pages_longterm to migrate pages allocated from > > > CMA region"). However, "Fixes" tag isn't added here since it is just > > > suboptimal but it doesn't cause any problem. > > > > But it is breaking the contract that the longterm pins never end up in a > > cma managed memory. So I think Fixes tag is really due. I am not sure > > about stable backport. If the patch was the trivial move of > > Previous implementation is correct since longterm pins never end up in a CMA > managed memory with that implementation. It's just a different and suboptimal > implementation to exclude the CMA area. This is why I don't add the "Fixes"A > tag on the patch.
But the current implementation calls memalloc_nocma_restore too early so __gu_longterm_locked will migrate pages possibly to CMA ranges as there is no GFP_MOVABLE restriction in place. Or am I missing something? -- Michal Hocko SUSE Labs
