diff options
Diffstat (limited to 'mm/khugepaged.c')
| -rw-r--r-- | mm/khugepaged.c | 57 |
1 files changed, 30 insertions, 27 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 3703a56571c1..5a7d2d5093f9 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1238,15 +1238,8 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, /* * Check if the page has any GUP (or other external) pins. * - * Here the check is racy it may see total_mapcount > refcount - * in some cases. - * For example, one process with one forked child process. - * The parent has the PMD split due to MADV_DONTNEED, then - * the child is trying unmap the whole PMD, but khugepaged - * may be scanning the parent between the child has - * PageDoubleMap flag cleared and dec the mapcount. So - * khugepaged may see total_mapcount > refcount. - * + * Here the check may be racy: + * it may see total_mapcount > refcount in some cases? * But such case is ephemeral we could always retry collapse * later. However it may report false positive if the page * has excessive GUP pins (i.e. 512). Anyway the same check @@ -1751,12 +1744,12 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, { struct address_space *mapping = file->f_mapping; struct page *hpage; - pgoff_t index, end = start + HPAGE_PMD_NR; + pgoff_t index = 0, end = start + HPAGE_PMD_NR; LIST_HEAD(pagelist); XA_STATE_ORDER(xas, &mapping->i_pages, start, HPAGE_PMD_ORDER); int nr_none = 0, result = SCAN_SUCCEED; bool is_shmem = shmem_file(file); - int nr; + int nr = 0; VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem); VM_BUG_ON(start & (HPAGE_PMD_NR - 1)); @@ -1796,6 +1789,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, xas_set(&xas, start); for (index = start; index < end; index++) { struct page *page = xas_next(&xas); + struct folio *folio; VM_BUG_ON(index != xas.xa_index); if (is_shmem) { @@ -1822,8 +1816,6 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, } if (xa_is_value(page) || !PageUptodate(page)) { - struct folio *folio; - xas_unlock_irq(&xas); /* swap in or instantiate fallocated page */ if (shmem_get_folio(mapping->host, index, @@ -1911,13 +1903,15 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, goto out_unlock; } - if (page_mapping(page) != mapping) { + folio = page_folio(page); + + if (folio_mapping(folio) != mapping) { result = SCAN_TRUNCATED; goto out_unlock; } - if (!is_shmem && (PageDirty(page) || - PageWriteback(page))) { + if (!is_shmem && (folio_test_dirty(folio) || + folio_test_writeback(folio))) { /* * khugepaged only works on read-only fd, so this * page is dirty because it hasn't been flushed @@ -1927,20 +1921,20 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, goto out_unlock; } - if (isolate_lru_page(page)) { + if (folio_isolate_lru(folio)) { result = SCAN_DEL_PAGE_LRU; goto out_unlock; } - if (page_has_private(page) && - !try_to_release_page(page, GFP_KERNEL)) { + if (folio_has_private(folio) && + !filemap_release_folio(folio, GFP_KERNEL)) { result = SCAN_PAGE_HAS_PRIVATE; - putback_lru_page(page); + folio_putback_lru(folio); goto out_unlock; } - if (page_mapped(page)) - try_to_unmap(page_folio(page), + if (folio_mapped(folio)) + try_to_unmap(folio, TTU_IGNORE_MLOCK | TTU_BATCH_FLUSH); xas_lock_irq(&xas); @@ -2019,6 +2013,7 @@ xa_unlocked: if (result == SCAN_SUCCEED) { struct page *page, *tmp; + struct folio *folio; /* * Replacing old pages with new one has succeeded, now we @@ -2046,11 +2041,13 @@ xa_unlocked: index++; } - SetPageUptodate(hpage); - page_ref_add(hpage, HPAGE_PMD_NR - 1); + folio = page_folio(hpage); + folio_mark_uptodate(folio); + folio_ref_add(folio, HPAGE_PMD_NR - 1); + if (is_shmem) - set_page_dirty(hpage); - lru_cache_add(hpage); + folio_mark_dirty(folio); + folio_add_lru(folio); /* * Remove pte page tables, so we can re-fault the page as huge. @@ -2108,7 +2105,8 @@ out: mem_cgroup_uncharge(page_folio(hpage)); put_page(hpage); } - /* TODO: tracepoints */ + + trace_mm_khugepaged_collapse_file(mm, hpage, index, is_shmem, addr, file, nr, result); return result; } @@ -2577,6 +2575,11 @@ void khugepaged_min_free_kbytes_update(void) mutex_unlock(&khugepaged_mutex); } +bool current_is_khugepaged(void) +{ + return kthread_func(current) == khugepaged; +} + static int madvise_collapse_errno(enum scan_result r) { /* |