From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751729AbcIHRXM (ORCPT ); Thu, 8 Sep 2016 13:23:12 -0400 Received: from mga03.intel.com ([134.134.136.65]:6206 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750750AbcIHRXK (ORCPT ); Thu, 8 Sep 2016 13:23:10 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,301,1470726000"; d="scan'208";a="876515908" From: "Huang\, Ying" To: "Kirill A. Shutemov" Cc: "Huang\, Ying" , Andrew Morton , , , , , , , Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel Subject: Re: [PATCH -v3 01/10] mm, swap: Make swap cluster size same of THP size on x86_64 References: <1473266769-2155-1-git-send-email-ying.huang@intel.com> <1473266769-2155-2-git-send-email-ying.huang@intel.com> <20160908110729.GC17331@node> Date: Thu, 08 Sep 2016 10:23:09 -0700 In-Reply-To: <20160908110729.GC17331@node> (Kirill A. Shutemov's message of "Thu, 8 Sep 2016 14:07:29 +0300") Message-ID: <878tv2tif6.fsf@yhuang-mobile.sh.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Kirill A. Shutemov" writes: > On Wed, Sep 07, 2016 at 09:46:00AM -0700, Huang, Ying wrote: >> From: Huang Ying >> >> In this patch, the size of the swap cluster is changed to that of the >> THP (Transparent Huge Page) on x86_64 architecture (512). This is for >> the THP swap support on x86_64. Where one swap cluster will be used to >> hold the contents of each THP swapped out. And some information of the >> swapped out THP (such as compound map count) will be recorded in the >> swap_cluster_info data structure. >> >> For other architectures which want THP swap support, THP_SWAP_CLUSTER >> need to be selected in the Kconfig file for the architecture. >> >> In effect, this will enlarge swap cluster size by 2 times on x86_64. >> Which may make it harder to find a free cluster when the swap space >> becomes fragmented. So that, this may reduce the continuous swap space >> allocation and sequential write in theory. The performance test in 0day >> shows no regressions caused by this. >> >> Cc: Hugh Dickins >> Cc: Shaohua Li >> Cc: Minchan Kim >> Cc: Rik van Riel >> Suggested-by: Andrew Morton >> Signed-off-by: "Huang, Ying" >> --- >> arch/x86/Kconfig | 1 + >> mm/Kconfig | 13 +++++++++++++ >> mm/swapfile.c | 4 ++++ >> 3 files changed, 18 insertions(+) >> >> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >> index 4c39728..421d862 100644 >> --- a/arch/x86/Kconfig >> +++ b/arch/x86/Kconfig >> @@ -164,6 +164,7 @@ config X86 >> select HAVE_STACK_VALIDATION if X86_64 >> select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS >> select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS >> + select ARCH_USES_THP_SWAP_CLUSTER if X86_64 >> >> config INSTRUCTION_DECODER >> def_bool y >> diff --git a/mm/Kconfig b/mm/Kconfig >> index be0ee11..2da8128 100644 >> --- a/mm/Kconfig >> +++ b/mm/Kconfig >> @@ -503,6 +503,19 @@ config FRONTSWAP >> >> If unsure, say Y to enable frontswap. >> >> +config ARCH_USES_THP_SWAP_CLUSTER >> + bool >> + default n >> + >> +config THP_SWAP_CLUSTER >> + bool >> + depends on SWAP && TRANSPARENT_HUGEPAGE && ARCH_USES_THP_SWAP_CLUSTER >> + default y >> + help >> + Use one swap cluster to hold the contents of the THP >> + (Transparent Huge Page) swapped out. The size of the swap >> + cluster will be same as that of THP. >> + >> config CMA >> bool "Contiguous Memory Allocator" >> depends on HAVE_MEMBLOCK && MMU >> diff --git a/mm/swapfile.c b/mm/swapfile.c >> index 8f1b97d..4b78402 100644 >> --- a/mm/swapfile.c >> +++ b/mm/swapfile.c >> @@ -196,7 +196,11 @@ static void discard_swap_cluster(struct swap_info_struct *si, >> } >> } >> >> +#ifdef CONFIG_THP_SWAP_CLUSTER >> +#define SWAPFILE_CLUSTER (HPAGE_SIZE / PAGE_SIZE) > > #define SWAPFILE_CLUSTER HPAGE_PMD_NR Yes. Will change it. > Note, HPAGE_SIZE is not nessesary HPAGE_PMD_SIZE. I can imagine an arch > with multiple huge page sizes where HPAGE_SIZE differs from what is used > for THP. Thanks for pointing out that! Best Regards, Huang, Ying