From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2884EC433DF for ; Tue, 20 Oct 2020 09:04:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8F612237B for ; Tue, 20 Oct 2020 09:04:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="QSTXCpyP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392372AbgJTJEM (ORCPT ); Tue, 20 Oct 2020 05:04:12 -0400 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:51402 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390499AbgJTJEJ (ORCPT ); Tue, 20 Oct 2020 05:04:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1603184648; x=1634720648; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=8x4DJKOYLh0gqQEMw739n/sQ0+LowFPlq4c5wDj0ivE=; b=QSTXCpyPBePeK2nzgPBSKEPgpGZImoKHuIPo5egOEa3lBSPGTI3+C5WQ GwEwXIp6rT7XG+IyC7uJMGSJM13KW1sKbeflECJQnrLZIkXvGJwDMU0pn W4tpFgQmVtTcm7isfYjRhED1BTsC2F4ThWhRxpwvzxZD2TsHThzayCOEb o=; X-IronPort-AV: E=Sophos;i="5.77,396,1596499200"; d="scan'208";a="60312483" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-1c1b5cdd.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 20 Oct 2020 09:03:58 +0000 Received: from EX13D31EUB001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2a-1c1b5cdd.us-west-2.amazon.com (Postfix) with ESMTPS id 985A8A1DAF; Tue, 20 Oct 2020 09:02:35 +0000 (UTC) Received: from u3f2cd687b01c55.ant.amazon.com (10.43.161.237) by EX13D31EUB001.ant.amazon.com (10.43.166.210) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 20 Oct 2020 09:02:15 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v22 05/18] mm/idle_page_tracking: Make PG_(idle|young) reusable Date: Tue, 20 Oct 2020 10:59:27 +0200 Message-ID: <20201020085940.13875-6-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201020085940.13875-1-sjpark@amazon.com> References: <20201020085940.13875-1-sjpark@amazon.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.161.237] X-ClientProxiedBy: EX13D41UWC001.ant.amazon.com (10.43.162.107) To EX13D31EUB001.ant.amazon.com (10.43.166.210) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: SeongJae Park PG_idle and PG_young allows the two PTE Accessed bit users, IDLE_PAGE_TRACKING and the reclaim logic concurrently work while don't interfere each other. That is, when they need to clear the Accessed bit, they set PG_young and PG_idle to represent the previous state of the bit, respectively. And when they need to read the bit, if the bit is cleared, they further read the PG_young and PG_idle, respectively, to know whether the other has cleared the bit meanwhile or not. We could add another page flag and extend the mechanism to use the flag if we need to add another concurrent PTE Accessed bit user subsystem. However, it would be only waste the space. Instead, if the new subsystem is mutually exclusive with IDLE_PAGE_TRACKING, it could simply reuse the PG_idle flag. However, it's impossible because the flags are dependent on IDLE_PAGE_TRACKING. To allow such reuse of the flags, this commit separates the PG_young and PG_idle flag logic from IDLE_PAGE_TRACKING and introduces new kernel config, 'PAGE_IDLE_FLAG'. Hence, if !IDLE_PAGE_TRACKING and IDLE_PAGE_FLAG, a new subsystem would be able to reuse PG_idle. In the next commit, DAMON's reference implementation of the virtual memory address space monitoring primitives will use it. Signed-off-by: SeongJae Park --- include/linux/page-flags.h | 4 ++-- include/linux/page_ext.h | 2 +- include/linux/page_idle.h | 6 +++--- include/trace/events/mmflags.h | 2 +- mm/Kconfig | 8 ++++++++ mm/page_ext.c | 12 +++++++++++- mm/page_idle.c | 10 ---------- 7 files changed, 26 insertions(+), 18 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 6be1aa559b1e..7736d290bb61 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -132,7 +132,7 @@ enum pageflags { #ifdef CONFIG_MEMORY_FAILURE PG_hwpoison, /* hardware poisoned page. Don't touch */ #endif -#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) +#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) PG_young, PG_idle, #endif @@ -432,7 +432,7 @@ static inline bool set_hwpoison_free_buddy_page(struct page *page) #define __PG_HWPOISON 0 #endif -#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) +#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) TESTPAGEFLAG(Young, young, PF_ANY) SETPAGEFLAG(Young, young, PF_ANY) TESTCLEARFLAG(Young, young, PF_ANY) diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h index cfce186f0c4e..c9cbc9756011 100644 --- a/include/linux/page_ext.h +++ b/include/linux/page_ext.h @@ -19,7 +19,7 @@ struct page_ext_operations { enum page_ext_flags { PAGE_EXT_OWNER, PAGE_EXT_OWNER_ALLOCATED, -#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) +#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT) PAGE_EXT_YOUNG, PAGE_EXT_IDLE, #endif diff --git a/include/linux/page_idle.h b/include/linux/page_idle.h index 1e894d34bdce..d8a6aecf99cb 100644 --- a/include/linux/page_idle.h +++ b/include/linux/page_idle.h @@ -6,7 +6,7 @@ #include #include -#ifdef CONFIG_IDLE_PAGE_TRACKING +#ifdef CONFIG_PAGE_IDLE_FLAG #ifdef CONFIG_64BIT static inline bool page_is_young(struct page *page) @@ -106,7 +106,7 @@ static inline void clear_page_idle(struct page *page) } #endif /* CONFIG_64BIT */ -#else /* !CONFIG_IDLE_PAGE_TRACKING */ +#else /* !CONFIG_PAGE_IDLE_FLAG */ static inline bool page_is_young(struct page *page) { @@ -135,6 +135,6 @@ static inline void clear_page_idle(struct page *page) { } -#endif /* CONFIG_IDLE_PAGE_TRACKING */ +#endif /* CONFIG_PAGE_IDLE_FLAG */ #endif /* _LINUX_MM_PAGE_IDLE_H */ diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index 5fb752034386..4d182c32071b 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -73,7 +73,7 @@ #define IF_HAVE_PG_HWPOISON(flag,string) #endif -#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) +#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT) #define IF_HAVE_PG_IDLE(flag,string) ,{1UL << flag, string} #else #define IF_HAVE_PG_IDLE(flag,string) diff --git a/mm/Kconfig b/mm/Kconfig index 19fe2251c87a..044317ef9143 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -761,10 +761,18 @@ config DEFERRED_STRUCT_PAGE_INIT lifetime of the system until these kthreads finish the initialisation. +config PAGE_IDLE_FLAG + bool "Add PG_idle and PG_young flags" + help + This feature adds PG_idle and PG_young flags in 'struct page'. PTE + Accessed bit writers can set the state of the bit in the flags to let + other PTE Accessed bit readers don't disturbed. + config IDLE_PAGE_TRACKING bool "Enable idle page tracking" depends on SYSFS && MMU select PAGE_EXTENSION if !64BIT + select PAGE_IDLE_FLAG help This feature allows to estimate the amount of user pages that have not been touched during a given period of time. This information can diff --git a/mm/page_ext.c b/mm/page_ext.c index a3616f7a0e9e..f9a6ff65ac0a 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -58,11 +58,21 @@ * can utilize this callback to initialize the state of it correctly. */ +#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT) +static bool need_page_idle(void) +{ + return true; +} +struct page_ext_operations page_idle_ops = { + .need = need_page_idle, +}; +#endif + static struct page_ext_operations *page_ext_ops[] = { #ifdef CONFIG_PAGE_OWNER &page_owner_ops, #endif -#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) +#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT) &page_idle_ops, #endif }; diff --git a/mm/page_idle.c b/mm/page_idle.c index 057c61df12db..144fb4ed961d 100644 --- a/mm/page_idle.c +++ b/mm/page_idle.c @@ -211,16 +211,6 @@ static const struct attribute_group page_idle_attr_group = { .name = "page_idle", }; -#ifndef CONFIG_64BIT -static bool need_page_idle(void) -{ - return true; -} -struct page_ext_operations page_idle_ops = { - .need = need_page_idle, -}; -#endif - static int __init page_idle_init(void) { int err; -- 2.17.1