From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755544AbbHQPJp (ORCPT ); Mon, 17 Aug 2015 11:09:45 -0400 Received: from mga02.intel.com ([134.134.136.20]:17421 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755356AbbHQPJn (ORCPT ); Mon, 17 Aug 2015 11:09:43 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,695,1432623600"; d="scan'208";a="770378533" From: "Kirill A. Shutemov" To: Andrew Morton , Hugh Dickins Cc: Andrea Arcangeli , Dave Hansen , Vlastimil Babka , Johannes Weiner , Michal Hocko , David Rientjes , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" Subject: [PATCHv2 0/4] Fix compound_head() race Date: Mon, 17 Aug 2015 18:09:01 +0300 Message-Id: <1439824145-25397-1-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.5.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Here's my attempt on fixing recently discovered race in compound_head(). It should make compound_head() reliable in all contexts. The patchset is against Linus' tree. Let me know if it need to be rebased onto different baseline. It's expected to have conflicts with my page-flags patchset and probably should be applied before it. v2: Per Hugh's suggestion page->compound_head is moved into third double word. This way we can avoid memory overhead which v1 had in some cases. This place in struct page is rather overloaded. More testing is required to make sure we don't collide with anyone. Kirill A. Shutemov (4): mm: drop page->slab_page zsmalloc: use page->private instead of page->first_page mm: pack compound_dtor and compound_order into one word in struct page mm: make compound_head() robust Documentation/vm/split_page_table_lock | 4 +- arch/xtensa/configs/iss_defconfig | 1 - include/linux/mm.h | 75 +++++++++---------------------- include/linux/mm_types.h | 20 ++++++--- include/linux/page-flags.h | 80 ++++++++-------------------------- mm/Kconfig | 12 ----- mm/debug.c | 5 --- mm/huge_memory.c | 3 +- mm/hugetlb.c | 16 +++---- mm/internal.h | 4 +- mm/memory-failure.c | 7 --- mm/page_alloc.c | 37 ++++++++++------ mm/swap.c | 4 +- mm/zsmalloc.c | 11 +++-- 14 files changed, 94 insertions(+), 185 deletions(-) -- 2.5.0