From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754106AbbCaBrM (ORCPT ); Mon, 30 Mar 2015 21:47:12 -0400 Received: from TYO202.gate.nec.co.jp ([210.143.35.52]:35217 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753633AbbCaBrJ convert rfc822-to-8bit (ORCPT ); Mon, 30 Mar 2015 21:47:09 -0400 From: Naoya Horiguchi To: Mel Gorman CC: Naoya Horiguchi , "linux-mm@kvack.org" , Andrew Morton , Hugh Dickins , "Kirill A. Shutemov" , "David Rientjes" , Rik van Riel , "linux-kernel@vger.kernel.org" Subject: [PATCH] mm: numa: disable change protection for vma(VM_HUGETLB) Thread-Topic: [PATCH] mm: numa: disable change protection for vma(VM_HUGETLB) Thread-Index: AQHQa1RtvOznTUkTLkWQBP/X/X+ynA== Date: Tue, 31 Mar 2015 01:45:55 +0000 Message-ID: <20150331014554.GA8128@hori1.linux.bs1.fc.nec.co.jp> References: <1427708426-31610-1-git-send-email-n-horiguchi@ah.jp.nec.com> <20150330102802.GQ4701@suse.de> <55192885.5010608@gmail.com> <20150330115901.GR4701@suse.de> In-Reply-To: <20150330115901.GR4701@suse.de> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.30] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 30, 2015 at 12:59:01PM +0100, Mel Gorman wrote: > On Mon, Mar 30, 2015 at 07:42:13PM +0900, Naoya Horiguchi wrote: ... > > I note now that the patch was too hasty. By rights, that check > should be covered by vma_migratable() but it's only checked if > CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION which means it's x86-only. If you > are seeing this problem on any other arch then a more correct fix might be > to remove the CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION check in vma_migratable. Changing vma_migratable() affects other usecases of hugepage migration like mbind(), so simply removing the ifdef doesn't work for such usecases. I didn't test other archs, but I guess that this problem could happen on all archs enabling numa balancing, whether it supports CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION. So I'd like pick/push your first suggestion. It passed my testing. Thanks, Naoya Horiguchi --- From: Naoya Horiguchi Subject: [PATCH] mm: numa: disable change protection for vma(VM_HUGETLB) Currently when a process accesses to hugetlb range protected with PROTNONE, unexpected COWs are triggered, which finally put hugetlb subsystem into broken/uncontrollable state, where for example h->resv_huge_pages is subtracted too much and wrapped around to a very large number, and free hugepage pool is no longer maintainable. This patch simply stops changing protection for vma(VM_HUGETLB) to fix the problem. And this also allows us to avoid useless overhead of minor faults. Suggested-by: Mel Gorman Signed-off-by: Naoya Horiguchi --- kernel/sched/fair.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7ce18f3c097a..6ad0d570f38e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2161,8 +2161,10 @@ void task_numa_work(struct callback_head *work) vma = mm->mmap; } for (; vma; vma = vma->vm_next) { - if (!vma_migratable(vma) || !vma_policy_mof(vma)) + if (!vma_migratable(vma) || !vma_policy_mof(vma) || + is_vm_hugetlb_page(vma)) { continue; + } /* * Shared library pages mapped by multiple processes are not -- 1.9.3