From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id CC13E6B0267 for ; Mon, 7 Nov 2016 14:08:14 -0500 (EST) Received: by mail-wm0-f72.google.com with SMTP id u144so66744217wmu.1 for ; Mon, 07 Nov 2016 11:08:14 -0800 (PST) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id t3si31014506wjt.215.2016.11.07.11.08.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Nov 2016 11:08:13 -0800 (PST) From: Johannes Weiner Subject: [PATCH 6/6] mm: workingset: restore refault tracking for single-page files Date: Mon, 7 Nov 2016 14:07:41 -0500 Message-Id: <20161107190741.3619-7-hannes@cmpxchg.org> In-Reply-To: <20161107190741.3619-1-hannes@cmpxchg.org> References: <20161107190741.3619-1-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Linus Torvalds , Jan Kara , "Kirill A. Shutemov" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Shadow entries in the page cache used to be accounted behind the radix tree implementation's back in the upper bits of node->count, and the radix tree code extending a single-entry tree with a shadow entry in root->rnode would corrupt that counter. As a result, we could not put shadow entries at index 0 if the tree didn't have any other entries, and that means no refault detection for any single-page file. Now that the shadow entries are tracked natively in the radix tree's exceptional counter, this is no longer necessary. Extending and shrinking the tree from and to single entries in root->rnode now does the right thing when the entry is exceptional, remove that limitation. Signed-off-by: Johannes Weiner --- mm/filemap.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 438f0b54f8fd..55a3b136a527 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -178,19 +178,12 @@ static void page_cache_tree_delete(struct address_space *mapping, radix_tree_clear_tags(&mapping->page_tree, node, slot); - if (!node) { - VM_BUG_ON_PAGE(nr != 1, page); - /* - * We need a node to properly account shadow - * entries. Don't plant any without. XXX - */ - shadow = NULL; - } - __radix_tree_replace(&mapping->page_tree, node, slot, shadow); - if (!node) + if (!node) { + VM_BUG_ON_PAGE(nr != 1, page); break; + } if (!shadow && __radix_tree_delete_node(&mapping->page_tree, node)) -- 2.10.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org