Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755748AbaAMQZF (ORCPT ); Mon, 13 Jan 2014 11:25:05 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:53525 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751916AbaAMQER (ORCPT ); Mon, 13 Jan 2014 11:04:17 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Mel Gorman , Alex Thorlton , Andrew Morton , Linus Torvalds , Luis Henriques Subject: [PATCH 3.11 146/208] mm: numa: do not clear PMD during PTE update scan Date: Mon, 13 Jan 2014 15:59:47 +0000 Message-Id: <1389628849-1614-147-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1389628849-1614-1-git-send-email-luis.henriques@canonical.com> References: <1389628849-1614-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Mel Gorman commit 5a6dac3ec5f583cc8ee7bc53b5500a207c4ca433 upstream. If the PMD is flushed then a parallel fault in handle_mm_fault() will enter the pmd_none and do_huge_pmd_anonymous_page() path where it'll attempt to insert a huge zero page. This is wasteful so the patch avoids clearing the PMD when setting pmd_numa. Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel Cc: Alex Thorlton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques --- mm/huge_memory.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 72da10d..ac2546c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1486,20 +1486,22 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, if (__pmd_trans_huge_lock(pmd, vma) == 1) { pmd_t entry; - entry = pmdp_get_and_clear(mm, addr, pmd); if (!prot_numa) { + entry = pmdp_get_and_clear(mm, addr, pmd); entry = pmd_modify(entry, newprot); BUG_ON(pmd_write(entry)); + set_pmd_at(mm, addr, pmd, entry); } else { struct page *page = pmd_page(*pmd); + entry = *pmd; /* only check non-shared pages */ if (page_mapcount(page) == 1 && !pmd_numa(*pmd)) { entry = pmd_mknuma(entry); + set_pmd_at(mm, addr, pmd, entry); } } - set_pmd_at(mm, addr, pmd, entry); spin_unlock(&vma->vm_mm->page_table_lock); ret = 1; } -- 1.8.3.2 -- 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/