From 5737df3826dee4287f986dc2eaf7dc352068710d Mon Sep 17 00:00:00 2001 From: Ackerley Tng Date: Thu, 2 Jul 2026 09:21:50 -0700 Subject: mm: hugetlb: refactor out hugetlb_alloc_folio() Refactor out hugetlb_alloc_folio() from alloc_hugetlb_folio(), which handles allocation of a folio and memory and HugeTLB charging to cgroups. This refactoring decouples the HugeTLB page allocation from VMAs, specifically: 1. Reservations (as in resv_map) are stored in the vma 2. mpol is stored at vma->vm_policy 3. A vma must be used for allocation even if the pages are not meant to be used by host process. Without this coupling, VMAs are no longer a requirement for allocation. This opens up the allocation routine for usage without VMAs, which will allow guest_memfd to use HugeTLB as a more generic allocator of huge pages, since guest_memfd memory may not have any associated VMAs by design. In addition, direct allocations from HugeTLB could possibly be refactored to avoid the use of a pseudo-VMA. Also, this decouples HugeTLB page allocation from HugeTLBfs, where the subpool is stored at the fs mount. This is also a requirement for guest_memfd, where the plan is to have a subpool created per-fd and stored on the inode. Provide and use alloc_flags to allow more allocation knobs in future without expanding the number of parameters in hugetlb_alloc_folio(). No functional change intended. Link: https://lore.kernel.org/20260702-hugetlb-open-up-v4-6-d53cefcccf34@google.com Signed-off-by: Ackerley Tng Cc: Alistair Popple Cc: Byungchul Park Cc: David Hildenbrand Cc: David Rientjes Cc: "Edgecombe, Rick P" Cc: Frank van der Linden Cc: Gregory Price Cc: "Huang, Ying" Cc: James Houghton Cc: Jason Gunthorpe Cc: Jiaqi Yan Cc: Joshua Hahn Cc: Matthew Brost Cc: Michael Roth Cc: Michal Hocko Cc: Muchun Song Cc: Oscar Salvador Cc: Paolo Bonzini Cc: Pasha Tatashin Cc: Peter Xu Cc: Pratyush Yadav Cc: Rakie Kim Cc: Roman Gushchin Cc: Sean Christopherson Cc: Shakeel Butt Cc: Shivank Garg Cc: Vishal Annapurve Cc: Yan Zhao Cc: Zi Yan Cc: Qi Zheng Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include/linux') diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 87c87f64bc05..817b8b4223fa 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -2,6 +2,7 @@ #ifndef _LINUX_HUGETLB_H #define _LINUX_HUGETLB_H +#include #include #include #include @@ -682,6 +683,23 @@ struct hstate { int isolate_or_dissolve_huge_folio(struct folio *folio, struct list_head *list); int replace_free_hugepage_folios(unsigned long start_pfn, unsigned long end_pfn); void wait_for_freed_hugetlb_folios(void); + +struct mempolicy_interpreted { + int nid; + nodemask_t *nodemask; + enum mempolicy_mode mode; +}; + +enum hugetlb_alloc_flag { + HUGETLB_ALLOC_CHARGE_CGROUP_RSVD_BIT = 0, + HUGETLB_ALLOC_USE_GLOBAL_RESERVATIONS_BIT, +}; + +#define HUGETLB_ALLOC_CHARG_CGROUP_RSVD BIT(HUGETLB_ALLOC_CHARGE_CGROUP_RSVD_BIT) +#define HUGETLB_ALLOC_USE_GLOBAL_RESERVATIONS BIT(HUGETLB_ALLOC_USE_GLOBAL_RESERVATIONS_BIT) + +struct folio *hugetlb_alloc_folio(struct hstate *h, + struct mempolicy_interpreted *mpoli, u8 alloc_flags); struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, unsigned long addr, bool cow_from_owner); struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, -- cgit v1.2.3