From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933422AbbGJRr4 (ORCPT ); Fri, 10 Jul 2015 13:47:56 -0400 Received: from mga11.intel.com ([192.55.52.93]:49733 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933086AbbGJRnF (ORCPT ); Fri, 10 Jul 2015 13:43:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,448,1432623600"; d="scan'208";a="759971280" 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: [PATCH 31/36] thp, mm: split_huge_page(): caller need to lock page Date: Fri, 10 Jul 2015 20:42:05 +0300 Message-Id: <1436550130-112636-32-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436550130-112636-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1436550130-112636-1-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 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 Acked-by: Vlastimil Babka --- mm/memory-failure.c | 10 ++++++++-- mm/migrate.c | 8 ++++++-- 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 1cf7f2988422..0d9989a36d32 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1143,15 +1143,18 @@ int memory_failure(unsigned long pfn, int trapno, int flags) put_page(hpage); return -EBUSY; } + lock_page(hpage); if (unlikely(split_huge_page(hpage))) { pr_err("MCE: %#lx: thp split failed\n", pfn); if (TestClearPageHWPoison(p)) atomic_long_sub(nr_pages, &num_poisoned_pages); + unlock_page(hpage); put_page(p); if (p != hpage) put_page(hpage); return -EBUSY; } + unlock_page(hpage); VM_BUG_ON_PAGE(!page_count(p), p); hpage = compound_head(p); } @@ -1714,10 +1717,13 @@ 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 dfd24cb7afc6..8bb2107b8751 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -933,9 +933,13 @@ 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