From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753597Ab3IED6Y (ORCPT ); Wed, 4 Sep 2013 23:58:24 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:64361 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752738Ab3IED6X (ORCPT ); Wed, 4 Sep 2013 23:58:23 -0400 Message-ID: <52280058.5070803@huawei.com> Date: Thu, 5 Sep 2013 11:54:00 +0800 From: Jianguo Wu User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Wanpeng Li CC: Jianguo Wu , , , , , , , Subject: Re: [PATCH] mm/thp: fix comments in transparent_hugepage_flags References: <1378301422-9468-1-git-send-email-wujianguo@huawei.com> <5227e870.ab42320a.62d4.3d12SMTPIN_ADDED_BROKEN@mx.google.com> <5227F4B6.40009@huawei.com> <20130905033704.GA18909@hacker.(null)> In-Reply-To: <20130905033704.GA18909@hacker.(null)> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.74.216] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2013/9/5 11:37, Wanpeng Li wrote: > On Thu, Sep 05, 2013 at 11:04:22AM +0800, Jianguo Wu wrote: >> Hi Wanpeng, >> >> On 2013/9/5 10:11, Wanpeng Li wrote: >> >>> Hi Jianguo, >>> On Wed, Sep 04, 2013 at 09:30:22PM +0800, Jianguo Wu wrote: >>>> Since commit d39d33c332(thp: enable direct defrag), defrag is enable >>>> for all transparent hugepage page faults by default, not only in >>>> MADV_HUGEPAGE regions. >>>> >>>> Signed-off-by: Jianguo Wu >>>> --- >>>> mm/huge_memory.c | 6 ++---- >>>> 1 file changed, 2 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >>>> index a92012a..abf047e 100644 >>>> --- a/mm/huge_memory.c >>>> +++ b/mm/huge_memory.c >>>> @@ -28,10 +28,8 @@ >>>> >>>> /* >>>> * By default transparent hugepage support is enabled for all mappings >>> >>> This is also stale. TRANSPARENT_HUGEPAGE_ALWAYS is not configured by default in >>> order that avoid to risk increase the memory footprint of applications w/o a >>> guaranteed benefit. >>> >> >> Right, how about this: >> >> By default transparent hugepage support is disabled in order that avoid to risk > > I don't think it's disabled. TRANSPARENT_HUGEPAGE_MADVISE is configured > by default. > Hi Wanpeng, We have TRANSPARENT_HUGEPAGE and TRANSPARENT_HUGEPAGE_ALWAYS/TRANSPARENT_HUGEPAGE_MADVISE, TRANSPARENT_HUGEPAGE_ALWAYS or TRANSPARENT_HUGEPAGE_MADVISE is configured only if TRANSPARENT_HUGEPAGE is configured. By default, TRANSPARENT_HUGEPAGE=n, and TRANSPARENT_HUGEPAGE_ALWAYS is configured when TRANSPARENT_HUGEPAGE=y. commit 13ece886d9(thp: transparent hugepage config choice): config TRANSPARENT_HUGEPAGE - bool "Transparent Hugepage Support" if EMBEDDED + bool "Transparent Hugepage Support" depends on X86 && MMU - default y +choice + prompt "Transparent Hugepage Support sysfs defaults" + depends on TRANSPARENT_HUGEPAGE + default TRANSPARENT_HUGEPAGE_ALWAYS Thanks, Jianguo Wu > Regards, > Wanpeng Li > >> increase the memory footprint of applications w/o a guaranteed benefit, and >> khugepaged scans all mappings when transparent hugepage enabled. >> Defrag is invoked by khugepaged hugepage allocations and by page faults for all >> hugepage allocations. >> >> Thanks, >> Jianguo Wu >> >>> Regards, >>> Wanpeng Li >>> >>>> - * and khugepaged scans all mappings. Defrag is only invoked by >>>> - * khugepaged hugepage allocations and by page faults inside >>>> - * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived >>>> - * allocations. >>>> + * and khugepaged scans all mappings. Defrag is invoked by khugepaged >>>> + * hugepage allocations and by page faults for all hugepage allocations. >>>> */ >>>> unsigned long transparent_hugepage_flags __read_mostly = >>>> #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS >>>> -- >>>> 1.8.1.2 >>>> >>>> -- >>>> To unsubscribe, send a message with 'unsubscribe linux-mm' in >>>> the body to majordomo@kvack.org. For more info on Linux MM, >>>> see: http://www.linux-mm.org/ . >>>> Don't email: email@kvack.org >>> >>> -- >>> To unsubscribe, send a message with 'unsubscribe linux-mm' in >>> the body to majordomo@kvack.org. For more info on Linux MM, >>> see: http://www.linux-mm.org/ . >>> Don't email: email@kvack.org >>> >>> >> >> > > > . >