From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx202.postini.com [74.125.245.202]) by kanga.kvack.org (Postfix) with SMTP id 9A9586B0031 for ; Thu, 5 Sep 2013 00:58:54 -0400 (EDT) Received: from /spool/local by e28smtp08.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 5 Sep 2013 10:17:12 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id D64C5394004E for ; Thu, 5 Sep 2013 10:28:36 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r8550YvD35061840 for ; Thu, 5 Sep 2013 10:30:38 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r854wi5a019959 for ; Thu, 5 Sep 2013 10:28:44 +0530 Date: Thu, 5 Sep 2013 12:58:42 +0800 From: Wanpeng Li Subject: Re: [PATCH] mm/thp: fix comments in transparent_hugepage_flags Message-ID: <20130905045842.GA25507@hacker.(null)> Reply-To: Wanpeng Li 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)> <52280058.5070803@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52280058.5070803@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: Jianguo Wu Cc: Jianguo Wu , akpm@linux-foundation.org, aarcange@redhat.com, kirill.shutemov@linux.intel.com, mgorman@suse.de, xiaoguangrong@linux.vnet.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Hi Jianguo, On Thu, Sep 05, 2013 at 11:54:00AM +0800, Jianguo Wu wrote: >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 > mmotm tree: grep 'TRANSPARENT_HUGEPAGE' .config CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y CONFIG_TRANSPARENT_HUGEPAGE=y # CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS is not set CONFIG_TRANSPARENT_HUGEPAGE_MADVISE=y distro: grep 'TRANSPARENT_HUGEPAGE' config-3.8.0-26-generic CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y CONFIG_TRANSPARENT_HUGEPAGE=y # CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS is not set CONFIG_TRANSPARENT_HUGEPAGE_MADVISE=y >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 >>>> >>>> >>> >>> >> >> >> . >> > > -- 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