From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Matthew Wilcox To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Matthew Wilcox , Jan Kara , Jeff Layton , Lukas Czerner , Ross Zwisler , Christoph Hellwig , Goldwyn Rodrigues , Nicholas Piggin , Ryusuke Konishi , linux-nilfs@vger.kernel.org, Jaegeuk Kim , Chao Yu , linux-f2fs-devel@lists.sourceforge.net Subject: [PATCH v14 65/74] dax: Convert dax_layout_busy_page to XArray Date: Sat, 16 Jun 2018 19:00:43 -0700 Message-Id: <20180617020052.4759-66-willy@infradead.org> In-Reply-To: <20180617020052.4759-1-willy@infradead.org> References: <20180617020052.4759-1-willy@infradead.org> Sender: owner-linux-mm@kvack.org List-ID: Instead of using a pagevec, just use the XArray iterators. Add a conditional rescheduling point which probably should have been there in the original. Signed-off-by: Matthew Wilcox --- fs/dax.c | 57 +++++++++++++++++++++----------------------------------- 1 file changed, 21 insertions(+), 36 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 71181f4bb1d3..7b80b17cba50 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -697,11 +697,10 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, */ struct page *dax_layout_busy_page(struct address_space *mapping) { - pgoff_t indices[PAGEVEC_SIZE]; + XA_STATE(xas, &mapping->i_pages, 0); + void *entry; + unsigned int scanned = 0; struct page *page = NULL; - struct pagevec pvec; - pgoff_t index, end; - unsigned i; /* * In the 'limited' case get_user_pages() for dax is disabled. @@ -712,13 +711,9 @@ struct page *dax_layout_busy_page(struct address_space *mapping) if (!dax_mapping(mapping) || !mapping_mapped(mapping)) return NULL; - pagevec_init(&pvec); - index = 0; - end = -1; - /* * If we race get_user_pages_fast() here either we'll see the - * elevated page count in the pagevec_lookup and wait, or + * elevated page count in the iteration and wait, or * get_user_pages_fast() will see that the page it took a reference * against is no longer mapped in the page tables and bail to the * get_user_pages() slow path. The slow path is protected by @@ -730,36 +725,26 @@ struct page *dax_layout_busy_page(struct address_space *mapping) */ unmap_mapping_range(mapping, 0, 0, 1); - while (index < end && pagevec_lookup_entries(&pvec, mapping, index, - min(end - index, (pgoff_t)PAGEVEC_SIZE), - indices)) { - for (i = 0; i < pagevec_count(&pvec); i++) { - struct page *pvec_ent = pvec.pages[i]; - void *entry; - - index = indices[i]; - if (index >= end) - break; - - if (!xa_is_value(pvec_ent)) - continue; - - xa_lock_irq(&mapping->i_pages); - entry = get_unlocked_mapping_entry(mapping, index, NULL); - if (entry) - page = dax_busy_page(entry); - put_unlocked_mapping_entry(mapping, index, entry); - xa_unlock_irq(&mapping->i_pages); - if (page) - break; - } - pagevec_remove_exceptionals(&pvec); - pagevec_release(&pvec); - index++; - + xas_lock_irq(&xas); + xas_for_each(&xas, entry, ULONG_MAX) { + if (!xa_is_value(entry)) + continue; + if (unlikely(dax_is_locked(entry))) + entry = get_unlocked_entry(&xas); + if (entry) + page = dax_busy_page(entry); + put_unlocked_entry(&xas, entry); if (page) break; + if (++scanned % XA_CHECK_SCHED) + continue; + + xas_pause(&xas); + xas_unlock_irq(&xas); + cond_resched(); + xas_lock_irq(&xas); } + xas_unlock_irq(&xas); return page; } EXPORT_SYMBOL_GPL(dax_layout_busy_page); -- 2.17.1