| Message ID | 20231220224504.646757-4-david@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/rmap: interface overhaul | expand |
> On Dec 21, 2023, at 06:44, David Hildenbrand <david@redhat.com> wrote: > > hugetlb rmap handling differs quite a lot from "ordinary" rmap code. > For example, hugetlb currently only supports entire mappings, and treats > any mapping as mapped using a single "logical PTE". Let's move it out > of the way so we can overhaul our "ordinary" rmap. > implementation/interface. > > Right now we're using page_dup_file_rmap() in some cases where "ordinary" > rmap code would have used page_add_file_rmap(). So let's introduce and > use hugetlb_add_file_rmap() instead. We won't be adding a > "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be > doing the same: "dup" is just an optimization for "add". > > What remains is a single page_dup_file_rmap() call in fork() code. > > Add sanity checks that we end up with the right folios in the right > functions. > > Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> > Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> > Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Thanks.
On Wed, Dec 20, 2023 at 11:44:27PM +0100, David Hildenbrand wrote: > hugetlb rmap handling differs quite a lot from "ordinary" rmap code. > For example, hugetlb currently only supports entire mappings, and treats > any mapping as mapped using a single "logical PTE". Let's move it out > of the way so we can overhaul our "ordinary" rmap. > implementation/interface. > > Right now we're using page_dup_file_rmap() in some cases where "ordinary" > rmap code would have used page_add_file_rmap(). So let's introduce and > use hugetlb_add_file_rmap() instead. We won't be adding a > "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be > doing the same: "dup" is just an optimization for "add". > > What remains is a single page_dup_file_rmap() call in fork() code. > > Add sanity checks that we end up with the right folios in the right > functions. > > Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> > Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> > Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 64ae6c4d72720..56900a16f41a6 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -211,6 +211,14 @@ void hugetlb_add_anon_rmap(struct folio *, struct vm_area_struct *, void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address); +static inline void hugetlb_add_file_rmap(struct folio *folio) +{ + VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); + VM_WARN_ON_FOLIO(folio_test_anon(folio), folio); + + atomic_inc(&folio->_entire_mapcount); +} + static inline void hugetlb_remove_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ef48ae6738909..57e8981879314 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5408,7 +5408,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, * sleep during the process. */ if (!folio_test_anon(pte_folio)) { - page_dup_file_rmap(&pte_folio->page, true); + hugetlb_add_file_rmap(pte_folio); } else if (page_try_dup_anon_rmap(&pte_folio->page, true, src_vma)) { pte_t src_pte_old = entry; @@ -6279,7 +6279,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, if (anon_rmap) hugetlb_add_new_anon_rmap(folio, vma, haddr); else - page_dup_file_rmap(&folio->page, true); + hugetlb_add_file_rmap(folio); new_pte = make_huge_pte(vma, &folio->page, ((vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_SHARED))); /* @@ -6730,7 +6730,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, goto out_release_unlock; if (folio_in_pagecache) - page_dup_file_rmap(&folio->page, true); + hugetlb_add_file_rmap(folio); else hugetlb_add_new_anon_rmap(folio, dst_vma, dst_addr); diff --git a/mm/migrate.c b/mm/migrate.c index 7d1c3f292d24d..0e912443a18c3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -252,7 +252,7 @@ static bool remove_migration_pte(struct folio *folio, hugetlb_add_anon_rmap(folio, vma, pvmw.address, rmap_flags); else - page_dup_file_rmap(new, true); + hugetlb_add_file_rmap(folio); set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte, psize); } else diff --git a/mm/rmap.c b/mm/rmap.c index 261e1af0d254f..a57ec926daf0c 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1395,6 +1395,7 @@ void folio_add_file_rmap_range(struct folio *folio, struct page *page, unsigned int nr_pmdmapped = 0, first; int nr = 0; + VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); VM_WARN_ON_FOLIO(compound && !folio_test_pmd_mappable(folio), folio); /* Is page being mapped by PTE? Is this its first map to be added? */