Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753956AbdC1Fcd (ORCPT ); Tue, 28 Mar 2017 01:32:33 -0400 Received: from mga06.intel.com ([134.134.136.31]:13176 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753449AbdC1Fc1 (ORCPT ); Tue, 28 Mar 2017 01:32:27 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,235,1486454400"; d="scan'208";a="1147757191" From: "Huang, Ying" To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel Subject: [PATCH -mm -v7 1/9] mm, swap: Make swap cluster size same of THP size on x86_64 Date: Tue, 28 Mar 2017 13:32:01 +0800 Message-Id: <20170328053209.25876-2-ying.huang@intel.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170328053209.25876-1-ying.huang@intel.com> References: <20170328053209.25876-1-ying.huang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2681 Lines: 85 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, ARCH_USES_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 abfc31fb0bee..852d13878793 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -178,6 +178,7 @@ config X86 select USER_STACKTRACE_SUPPORT select VIRT_TO_BUS select X86_FEATURE_NAMES if PROC_FS + select ARCH_USES_THP_SWAP_CLUSTER if X86_64 config INSTRUCTION_DECODER def_bool y diff --git a/mm/Kconfig b/mm/Kconfig index 9b8fccb969dc..7b708e200c29 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -499,6 +499,19 @@ 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 53b5881ee0d6..abc401f72a0a 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -199,7 +199,11 @@ static void discard_swap_cluster(struct swap_info_struct *si, } } +#ifdef CONFIG_THP_SWAP_CLUSTER +#define SWAPFILE_CLUSTER HPAGE_PMD_NR +#else #define SWAPFILE_CLUSTER 256 +#endif #define LATENCY_LIMIT 256 static inline void cluster_set_flag(struct swap_cluster_info *info, -- 2.11.0