diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c index 30e6d0248a3d..a7bf87cf2ba0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1313,6 +1313,17 @@ struct zap_details { struct folio *single_folio; /* Locked folio to be unmapped */ }; +/* Whether we should zap all COWed (private) pages too */ +static inline bool should_zap_cows(struct zap_details *details) +{ + /* By default, zap all pages */ + if (!details) + return true; + + /* Or, we zap COWed pages only if the caller wants to */ + return !details->zap_mapping; +} + /* * We set details->zap_mapping when we want to unmap shared but keep private * pages. Return true if skip zapping this page, false otherwise. @@ -1320,11 +1331,15 @@ struct zap_details { static inline bool zap_skip_check_mapping(struct zap_details *details, struct page *page) { - if (!details || !page) + /* If we can make a decision without *page.. */ + if (should_zap_cows(details)) + return false; + + /* E.g. the caller passes NULL for the case of a zero page */ + if (!page) return false; - return details->zap_mapping && - (details->zap_mapping != page_rmapping(page)); + return details->zap_mapping != page_rmapping(page); } static unsigned long zap_pte_range(struct mmu_gather *tlb, @@ -1405,17 +1420,24 @@ again: continue; } - /* If details->check_mapping, we leave swap entries. */ - if (unlikely(details)) - continue; - - if (!non_swap_entry(entry)) + if (!non_swap_entry(entry)) { + /* Genuine swap entry, hence a private anon page */ + if (!should_zap_cows(details)) + continue; rss[MM_SWAPENTS]--; - else if (is_migration_entry(entry)) { + } else if (is_migration_entry(entry)) { struct page *page; page = pfn_swap_entry_to_page(entry); + if (zap_skip_check_mapping(details, page)) + continue; rss[mm_counter(page)]--; + } else if (is_hwpoison_entry(entry)) { + if (!should_zap_cows(details)) + continue; + } else { + /* We should have covered all the swap entry types */ + WARN_ON_ONCE(1); } if (unlikely(!free_swap_and_cache(entry))) print_bad_pte(vma, addr, ptent, NULL); |