From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752784AbcFFONa (ORCPT ); Mon, 6 Jun 2016 10:13:30 -0400 Received: from mga14.intel.com ([192.55.52.115]:3587 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752559AbcFFOHz (ORCPT ); Mon, 6 Jun 2016 10:07:55 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,427,1459839600"; d="scan'208";a="822609769" From: "Kirill A. Shutemov" To: Hugh Dickins , Andrea Arcangeli , Andrew Morton Cc: Dave Hansen , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Jerome Marchand , Yang Shi , Sasha Levin , Andres Lagar-Cavilla , Ning Qu , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv9 27/32] khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page() Date: Mon, 6 Jun 2016 17:07:04 +0300 Message-Id: <1465222029-45942-28-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1465222029-45942-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1465222029-45942-1-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 Both variants of khugepaged_alloc_page() do up_read(&mm->mmap_sem) first: no point keep it inside the function. Signed-off-by: Kirill A. Shutemov --- mm/khugepaged.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 6357445ddd1c..3cf38dea4b75 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -740,19 +740,10 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) } static struct page * -khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm, - unsigned long address, int node) +khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node) { VM_BUG_ON_PAGE(*hpage, *hpage); - /* - * Before allocating the hugepage, release the mmap_sem read lock. - * The allocation can take potentially a long time if it involves - * sync compaction, and we do not need to hold the mmap_sem during - * that. We will recheck the vma after taking it again in write mode. - */ - up_read(&mm->mmap_sem); - *hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER); if (unlikely(!*hpage)) { count_vm_event(THP_COLLAPSE_ALLOC_FAILED); @@ -813,10 +804,8 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) } static struct page * -khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm, - unsigned long address, int node) +khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node) { - up_read(&mm->mmap_sem); VM_BUG_ON(!*hpage); return *hpage; @@ -936,8 +925,14 @@ static void collapse_huge_page(struct mm_struct *mm, /* Only allocate from the target node */ gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_OTHER_NODE | __GFP_THISNODE; - /* release the mmap_sem read lock. */ - new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node); + /* + * Before allocating the hugepage, release the mmap_sem read lock. + * The allocation can take potentially a long time if it involves + * sync compaction, and we do not need to hold the mmap_sem during + * that. We will recheck the vma after taking it again in write mode. + */ + up_read(&mm->mmap_sem); + new_page = khugepaged_alloc_page(hpage, gfp, node); if (!new_page) { result = SCAN_ALLOC_HUGE_PAGE_FAIL; goto out_nolock; -- 2.8.1