Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756312Ab3C1PaH (ORCPT ); Thu, 28 Mar 2013 11:30:07 -0400 Received: from mga11.intel.com ([192.55.52.93]:17228 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753761Ab3C1PaF (ORCPT ); Thu, 28 Mar 2013 11:30:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,927,1355126400"; d="scan'208";a="309808599" From: "Kirill A. Shutemov" To: Dave Cc: "Kirill A. Shutemov" , Andrea Arcangeli , Andrew Morton , Al Viro , Hugh Dickins , Wu Fengguang , Jan Kara , Mel Gorman , linux-mm@kvack.org, Andi Kleen , Matthew Wilcox , "Kirill A. Shutemov" , Hillf Danton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <514CA325.3010104@sr71.net> References: <1363283435-7666-1-git-send-email-kirill.shutemov@linux.intel.com> <1363283435-7666-19-git-send-email-kirill.shutemov@linux.intel.com> <514CA325.3010104@sr71.net> Subject: Re: [PATCHv2, RFC 18/30] thp, mm: truncate support for transparent huge page cache Content-Transfer-Encoding: 7bit Message-Id: <20130328153152.54DDAE0085@blue.fi.intel.com> Date: Thu, 28 Mar 2013 17:31:52 +0200 (EET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1071 Lines: 35 Dave wrote: > On 03/14/2013 10:50 AM, Kirill A. Shutemov wrote: > > @@ -280,6 +291,7 @@ void truncate_inode_pages_range(struct address_space *mapping, > > if (index > end) > > break; > > > > + VM_BUG_ON(PageTransHuge(page)); > > lock_page(page); > > WARN_ON(page->index != index); > > wait_on_page_writeback(page); > > This looks to be during the second truncate pass where things are > allowed to block. What's the logic behind it not being possible to > encounter TransHugePage()s here? Good question. The only way how the page can be created from under us is collapsing, but it's not implemented for file pages and I'm not sure yet how to implement it... Probably, I'll replace the BUG with if (PageTransHuge(page)) split_huge_page(page); It should be good enough. -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/