diff options
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 51 |
1 files changed, 26 insertions, 25 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 750e779c23db..4a30de98a8c7 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -4111,28 +4111,40 @@ static void filemap_cachestat(struct address_space *mapping, rcu_read_lock(); xas_for_each(&xas, folio, last_index) { + int order; unsigned long nr_pages; pgoff_t folio_first_index, folio_last_index; + /* + * Don't deref the folio. It is not pinned, and might + * get freed (and reused) underneath us. + * + * We *could* pin it, but that would be expensive for + * what should be a fast and lightweight syscall. + * + * Instead, derive all information of interest from + * the rcu-protected xarray. + */ + if (xas_retry(&xas, folio)) continue; + order = xa_get_order(xas.xa, xas.xa_index); + nr_pages = 1 << order; + folio_first_index = round_down(xas.xa_index, 1 << order); + folio_last_index = folio_first_index + nr_pages - 1; + + /* Folios might straddle the range boundaries, only count covered pages */ + if (folio_first_index < first_index) + nr_pages -= first_index - folio_first_index; + + if (folio_last_index > last_index) + nr_pages -= folio_last_index - last_index; + if (xa_is_value(folio)) { /* page is evicted */ void *shadow = (void *)folio; bool workingset; /* not used */ - int order = xa_get_order(xas.xa, xas.xa_index); - - nr_pages = 1 << order; - folio_first_index = round_down(xas.xa_index, 1 << order); - folio_last_index = folio_first_index + nr_pages - 1; - - /* Folios might straddle the range boundaries, only count covered pages */ - if (folio_first_index < first_index) - nr_pages -= first_index - folio_first_index; - - if (folio_last_index > last_index) - nr_pages -= folio_last_index - last_index; cs->nr_evicted += nr_pages; @@ -4150,24 +4162,13 @@ static void filemap_cachestat(struct address_space *mapping, goto resched; } - nr_pages = folio_nr_pages(folio); - folio_first_index = folio_pgoff(folio); - folio_last_index = folio_first_index + nr_pages - 1; - - /* Folios might straddle the range boundaries, only count covered pages */ - if (folio_first_index < first_index) - nr_pages -= first_index - folio_first_index; - - if (folio_last_index > last_index) - nr_pages -= folio_last_index - last_index; - /* page is in cache */ cs->nr_cache += nr_pages; - if (folio_test_dirty(folio)) + if (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY)) cs->nr_dirty += nr_pages; - if (folio_test_writeback(folio)) + if (xas_get_mark(&xas, PAGECACHE_TAG_WRITEBACK)) cs->nr_writeback += nr_pages; resched: |