diff options
Diffstat (limited to 'mm/hugetlb_vmemmap.c')
| -rw-r--r-- | mm/hugetlb_vmemmap.c | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 0c3f56b3578e..57b7f591eee8 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -43,6 +43,8 @@ struct vmemmap_remap_walk { #define VMEMMAP_SPLIT_NO_TLB_FLUSH BIT(0) /* Skip the TLB flush when we remap the PTE */ #define VMEMMAP_REMAP_NO_TLB_FLUSH BIT(1) +/* synchronize_rcu() to avoid writes from page_ref_add_unless() */ +#define VMEMMAP_SYNCHRONIZE_RCU BIT(2) unsigned long flags; }; @@ -457,6 +459,9 @@ static int __hugetlb_vmemmap_restore_folio(const struct hstate *h, if (!folio_test_hugetlb_vmemmap_optimized(folio)) return 0; + if (flags & VMEMMAP_SYNCHRONIZE_RCU) + synchronize_rcu(); + vmemmap_end = vmemmap_start + hugetlb_vmemmap_size(h); vmemmap_reuse = vmemmap_start; vmemmap_start += HUGETLB_VMEMMAP_RESERVE_SIZE; @@ -489,10 +494,7 @@ static int __hugetlb_vmemmap_restore_folio(const struct hstate *h, */ int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio) { - /* avoid writes from page_ref_add_unless() while unfolding vmemmap */ - synchronize_rcu(); - - return __hugetlb_vmemmap_restore_folio(h, folio, 0); + return __hugetlb_vmemmap_restore_folio(h, folio, VMEMMAP_SYNCHRONIZE_RCU); } /** @@ -515,14 +517,14 @@ long hugetlb_vmemmap_restore_folios(const struct hstate *h, struct folio *folio, *t_folio; long restored = 0; long ret = 0; - - /* avoid writes from page_ref_add_unless() while unfolding vmemmap */ - synchronize_rcu(); + unsigned long flags = VMEMMAP_REMAP_NO_TLB_FLUSH | VMEMMAP_SYNCHRONIZE_RCU; list_for_each_entry_safe(folio, t_folio, folio_list, lru) { if (folio_test_hugetlb_vmemmap_optimized(folio)) { - ret = __hugetlb_vmemmap_restore_folio(h, folio, - VMEMMAP_REMAP_NO_TLB_FLUSH); + ret = __hugetlb_vmemmap_restore_folio(h, folio, flags); + /* only need to synchronize_rcu() once for each batch */ + flags &= ~VMEMMAP_SYNCHRONIZE_RCU; + if (ret) break; restored++; @@ -570,6 +572,9 @@ static int __hugetlb_vmemmap_optimize_folio(const struct hstate *h, return ret; static_branch_inc(&hugetlb_optimize_vmemmap_key); + + if (flags & VMEMMAP_SYNCHRONIZE_RCU) + synchronize_rcu(); /* * Very Subtle * If VMEMMAP_REMAP_NO_TLB_FLUSH is set, TLB flushing is not performed @@ -617,10 +622,7 @@ void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio) { LIST_HEAD(vmemmap_pages); - /* avoid writes from page_ref_add_unless() while folding vmemmap */ - synchronize_rcu(); - - __hugetlb_vmemmap_optimize_folio(h, folio, &vmemmap_pages, 0); + __hugetlb_vmemmap_optimize_folio(h, folio, &vmemmap_pages, VMEMMAP_SYNCHRONIZE_RCU); free_vmemmap_page_list(&vmemmap_pages); } @@ -647,6 +649,7 @@ void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_l { struct folio *folio; LIST_HEAD(vmemmap_pages); + unsigned long flags = VMEMMAP_REMAP_NO_TLB_FLUSH | VMEMMAP_SYNCHRONIZE_RCU; list_for_each_entry(folio, folio_list, lru) { int ret = hugetlb_vmemmap_split_folio(h, folio); @@ -663,14 +666,12 @@ void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_l flush_tlb_all(); - /* avoid writes from page_ref_add_unless() while folding vmemmap */ - synchronize_rcu(); - list_for_each_entry(folio, folio_list, lru) { int ret; - ret = __hugetlb_vmemmap_optimize_folio(h, folio, &vmemmap_pages, - VMEMMAP_REMAP_NO_TLB_FLUSH); + ret = __hugetlb_vmemmap_optimize_folio(h, folio, &vmemmap_pages, flags); + /* only need to synchronize_rcu() once for each batch */ + flags &= ~VMEMMAP_SYNCHRONIZE_RCU; /* * Pages to be freed may have been accumulated. If we @@ -684,8 +685,7 @@ void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_l flush_tlb_all(); free_vmemmap_page_list(&vmemmap_pages); INIT_LIST_HEAD(&vmemmap_pages); - __hugetlb_vmemmap_optimize_folio(h, folio, &vmemmap_pages, - VMEMMAP_REMAP_NO_TLB_FLUSH); + __hugetlb_vmemmap_optimize_folio(h, folio, &vmemmap_pages, flags); } } |