Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753474AbaFJWFJ (ORCPT ); Tue, 10 Jun 2014 18:05:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59154 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002AbaFJWFH (ORCPT ); Tue, 10 Jun 2014 18:05:07 -0400 Date: Wed, 11 Jun 2014 00:04:51 +0200 From: Andrea Arcangeli To: "Kirill A. Shutemov" Cc: Christoph Lameter , "Kirill A. Shutemov" , Andrew Morton , Dave Hansen , Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH, RFC 00/10] THP refcounting redesign Message-ID: <20140610220451.GG19660@redhat.com> References: <1402329861-7037-1-git-send-email-kirill.shutemov@linux.intel.com> <20140610204640.GA9594@node.dhcp.inet.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140610204640.GA9594@node.dhcp.inet.fi> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 10, 2014 at 11:46:40PM +0300, Kirill A. Shutemov wrote: > Agreed. The patchset drops tail page refcounting. Very possibly I misread something or a later patch fixes this up, I just did a basic code review, but from the new code of split_huge_page it looks like it returns -EBUSY after checking the individual tail page refcounts, so it's not clear how that defines as "dropped". + for (i = 0; i < HPAGE_PMD_NR; i++) + tail_count += page_mapcount(page + i); + if (tail_count != page_count(page) - 1) { + BUG_ON(tail_count > page_count(page) - 1); + compound_unlock(page); + spin_unlock_irq(&zone->lru_lock); + return -EBUSY; -- 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/