Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031089AbbDWVF5 (ORCPT ); Thu, 23 Apr 2015 17:05:57 -0400 Received: from mga03.intel.com ([134.134.136.65]:27757 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031012AbbDWVFC (ORCPT ); Thu, 23 Apr 2015 17:05:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,634,1422950400"; d="scan'208";a="484855357" From: "Kirill A. Shutemov" To: Andrew Morton , Andrea Arcangeli , Hugh Dickins Cc: Dave Hansen , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" Subject: [PATCHv5 24/28] thp, mm: split_huge_page(): caller need to lock page Date: Fri, 24 Apr 2015 00:03:59 +0300 Message-Id: <1429823043-157133-25-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2295 Lines: 74 We're going to use migration entries instead of compound_lock() to stabilize page refcounts. Setup and remove migration entries require page to be locked. Some of split_huge_page() callers already have the page locked. Let's require everybody to lock the page before calling split_huge_page(). Signed-off-by: Kirill A. Shutemov Tested-by: Sasha Levin --- mm/memory-failure.c | 12 +++++++++--- mm/migrate.c | 8 ++++++-- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 441eff52d099..d9b06727e480 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -996,7 +996,10 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn, * enough * to be safe. */ if (!PageHuge(hpage) && PageAnon(hpage)) { - if (unlikely(split_huge_page(hpage))) { + lock_page(hpage); + ret = split_huge_page(hpage); + unlock_page(hpage); + if (unlikely(ret)) { /* * FIXME: if splitting THP is failed, it is * better to stop the following operation rather @@ -1750,10 +1753,13 @@ int soft_offline_page(struct page *page, int flags) return -EBUSY; } if (!PageHuge(page) && PageTransHuge(hpage)) { - if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) { + lock_page(page); + ret = split_huge_page(hpage); + unlock_page(page); + if (unlikely(ret)) { pr_info("soft offline: %#lx: failed to split THP\n", pfn); - return -EBUSY; + return ret; } } diff --git a/mm/migrate.c b/mm/migrate.c index b51e88c9dba2..03b9c4ba56dc 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -932,9 +932,13 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, goto out; } - if (unlikely(PageTransHuge(page))) - if (unlikely(split_huge_page(page))) + if (unlikely(PageTransHuge(page))) { + lock_page(page); + rc = split_huge_page(page); + unlock_page(page); + if (rc) goto out; + } rc = __unmap_and_move(page, newpage, force, mode); -- 2.1.4 -- 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/