From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id B928B6B026C for ; Mon, 25 Jul 2016 20:36:38 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id h186so434987039pfg.3 for ; Mon, 25 Jul 2016 17:36:38 -0700 (PDT) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTP id u3si36044024pay.67.2016.07.25.17.36.22 for ; Mon, 25 Jul 2016 17:36:33 -0700 (PDT) From: "Kirill A. Shutemov" Subject: [PATCHv1, RFC 12/33] truncate: make sure invalidate_mapping_pages() can discard huge pages Date: Tue, 26 Jul 2016 03:35:14 +0300 Message-Id: <1469493335-3622-13-git-send-email-kirill.shutemov@linux.intel.com> In-Reply-To: <1469493335-3622-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1469493335-3622-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Theodore Ts'o , Andreas Dilger , Jan Kara Cc: Alexander Viro , Hugh Dickins , Andrea Arcangeli , Andrew Morton , Dave Hansen , Vlastimil Babka , Matthew Wilcox , Ross Zwisler , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, "Kirill A. Shutemov" invalidate_inode_page() has expectation about page_count() of the page -- if it's not 2 (one to caller, one to radix-tree), it will not be dropped. That condition almost never met for THPs -- tail pages are pinned to the pagevec. Let's drop them, before calling invalidate_inode_page(). Signed-off-by: Kirill A. Shutemov --- mm/truncate.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/truncate.c b/mm/truncate.c index a01cce450a26..ce904e4b1708 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -504,10 +504,21 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, /* 'end' is in the middle of THP */ if (index == round_down(end, HPAGE_PMD_NR)) continue; + /* + * invalidate_inode_page() expects + * page_count(page) == 2 to drop page from page + * cache -- drop tail pages references. + */ + get_page(page); + pagevec_release(&pvec); } ret = invalidate_inode_page(page); unlock_page(page); + + if (PageTransHuge(page)) + put_page(page); + /* * Invalidation is a hint that the page is no longer * of interest and try to speed up its reclaim. -- 2.8.1 -- 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