From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: [PATCH v9 31/61] page cache: Convert filemap_range_has_page to XArray Date: Tue, 13 Mar 2018 06:26:09 -0700 Message-ID: <20180313132639.17387-32-willy@infradead.org> References: <20180313132639.17387-1-willy@infradead.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=TUtEh0M91EPdkADjFqpMeEIRJ3g2LkGH+aLO+Cd7bW8=; b=BPq+i0sH4X8mQQ3hYKfgA4pB6 lMf3JutbTRpYlzl7vOVMlWV9Am8sMC6At5bhiG+aa1rQUsC6nkTzaMknlz0/yPTn3/f5uydzF7RAd gi/yoZClIFwQR9i0pyxfw1RpaB4JMqByS9/HUQyJg0+8z9eH1F9Gz7B/6qrO9n9U3LvhyyluKB6ti JYXYfcfGVMoh+Lpe5PwpkCW8DtoRuhcPcAj2lfSMAfOeItyhpEpCjz90gRJEEwucaY9H+ftBvihH5 +3QYvK4Q97sYgGZQLRYj35Q4kah1BdparUIqtOAI6x+M7uMV2u0L5Gc6TQFmUsd7Pyk9rMPyMvHFB In-Reply-To: <20180313132639.17387-1-willy@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: Matthew Wilcox , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Ryusuke Konishi , linux-nilfs@vger.kernel.org From: Matthew Wilcox Instead of calling find_get_pages_range() and putting any reference, use xas_find() to iterate over any entries in the range, skipping the shadow/swap entries. Signed-off-by: Matthew Wilcox --- mm/filemap.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 86c83014c909..9bc417913269 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -458,20 +458,30 @@ EXPORT_SYMBOL(filemap_flush); bool filemap_range_has_page(struct address_space *mapping, loff_t start_byte, loff_t end_byte) { - pgoff_t index = start_byte >> PAGE_SHIFT; - pgoff_t end = end_byte >> PAGE_SHIFT; struct page *page; + XA_STATE(xas, &mapping->i_pages, start_byte >> PAGE_SHIFT); + pgoff_t max = end_byte >> PAGE_SHIFT; if (end_byte < start_byte) return false; - if (mapping->nrpages == 0) - return false; + rcu_read_lock(); + do { + page = xas_find(&xas, max); + if (xas_retry(&xas, page)) + continue; + /* Shadow entries don't count */ + if (xa_is_value(page)) + continue; + /* + * We don't need to try to pin this page; we're about to + * release the RCU lock anyway. It is enough to know that + * there was a page here recently. + */ + } while (0); + rcu_read_unlock(); - if (!find_get_pages_range(mapping, &index, end, 1, &page)) - return false; - put_page(page); - return true; + return page != NULL; } EXPORT_SYMBOL(filemap_range_has_page); -- 2.16.1