From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752573Ab2HIJIj (ORCPT ); Thu, 9 Aug 2012 05:08:39 -0400 Received: from mga11.intel.com ([192.55.52.93]:33777 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996Ab2HIJIh (ORCPT ); Thu, 9 Aug 2012 05:08:37 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,739,1336374000"; d="scan'208";a="195262071" From: "Kirill A. Shutemov" To: Andrew Morton , Andrea Arcangeli , linux-mm@kvack.org Cc: Andi Kleen , "H. Peter Anvin" , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , "Kirill A. Shutemov" Subject: [PATCH, RFC 1/9] thp: huge zero page: basic preparation Date: Thu, 9 Aug 2012 12:08:12 +0300 Message-Id: <1344503300-9507-2-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1344503300-9507-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1344503300-9507-1-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 From: "Kirill A. Shutemov" For now let's allocate the page on hugepage_init(). We'll switch to lazy allocation later. We are not going to map the huge zero page until we can handle it properly on all code paths. is_huge_zero_{pfn,pmd}() functions will be used by following patches to check whether the pfn/pmd is huge zero page. Signed-off-by: Kirill A. Shutemov --- mm/huge_memory.c | 29 +++++++++++++++++++++++++++++ 1 files changed, 29 insertions(+), 0 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 57c4b93..88e0a7a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -46,6 +46,7 @@ static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; /* during fragmentation poll the hugepage allocator once every minute */ static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; static struct task_struct *khugepaged_thread __read_mostly; +static unsigned long huge_zero_pfn __read_mostly; static DEFINE_MUTEX(khugepaged_mutex); static DEFINE_SPINLOCK(khugepaged_mm_lock); static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); @@ -167,6 +168,28 @@ out: return err; } +static int init_huge_zero_page(void) +{ + struct page *hpage; + + hpage = alloc_pages(GFP_TRANSHUGE | __GFP_ZERO, HPAGE_PMD_ORDER); + if (!hpage) + return -ENOMEM; + + huge_zero_pfn = page_to_pfn(hpage); + return 0; +} + +static inline bool is_huge_zero_pfn(unsigned long pfn) +{ + return pfn == huge_zero_pfn; +} + +static inline bool is_huge_zero_pmd(pmd_t pmd) +{ + return is_huge_zero_pfn(pmd_pfn(pmd)); +} + #ifdef CONFIG_SYSFS static ssize_t double_flag_show(struct kobject *kobj, @@ -550,6 +573,10 @@ static int __init hugepage_init(void) if (err) return err; + err = init_huge_zero_page(); + if (err) + goto out; + err = khugepaged_slab_init(); if (err) goto out; @@ -574,6 +601,8 @@ static int __init hugepage_init(void) return 0; out: + if (huge_zero_pfn) + __free_page(pfn_to_page(huge_zero_pfn)); hugepage_exit_sysfs(hugepage_kobj); return err; } -- 1.7.7.6