From patchwork Tue Jun 2 13:01:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11583765 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D24E4913 for ; Tue, 2 Jun 2020 13:04:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9EAA0206A4 for ; Tue, 2 Jun 2020 13:04:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="r5oz5Z/Y" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9EAA0206A4 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C99DB280077; Tue, 2 Jun 2020 09:04:17 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id C6F148E0006; Tue, 2 Jun 2020 09:04:17 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BAB0F280077; Tue, 2 Jun 2020 09:04:17 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0006.hostedemail.com [216.40.44.6]) by kanga.kvack.org (Postfix) with ESMTP id A41408E0006 for ; Tue, 2 Jun 2020 09:04:17 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5DBFF8248047 for ; Tue, 2 Jun 2020 13:04:17 +0000 (UTC) X-FDA: 76884290154.23.swing56_8f19adaa00241 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 0F6B738349 for ; Tue, 2 Jun 2020 13:03:04 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,prvs=4158b5ced=sjpark@amazon.com,,RULES_HIT:30054:30064,0,RBL:207.171.190.10:@amazon.com:.lbl8.mailshell.net-66.10.201.10 62.18.0.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:28,LUA_SUMMARY:none X-HE-Tag: swing56_8f19adaa00241 X-Filterd-Recvd-Size: 3955 Received: from smtp-fw-33001.amazon.com (smtp-fw-33001.amazon.com [207.171.190.10]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Tue, 2 Jun 2020 13:03:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1591102983; x=1622638983; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=tzqFpBqYuNYdmIDQaxDJFoQHYQ6t1Uuo0vpOOKcI5WQ=; b=r5oz5Z/Y/2IsXEwQwARkCvnOfUPj6BRz9pS/qdSZruH1jTsQtPJ50dWS 35Z+S4V2UsGpMHbFiMw529xzkm8xGkPDbLsufa2Kiwa8H4OnM0Naf35qn TQmQgroz+C9kAuu6molcuIM3u3YQ8JuJ2GUE7hBdU32pndWjAuR/5+ocR 0=; IronPort-SDR: qoYsmQOdqA0pkwrJpX8ri3TNLi/W0XXlTF2bAtoSIfVfTLYiiwvKW3I7lGTGd+lpXB4NQets+z Ry58Vym9o7AQ== X-IronPort-AV: E=Sophos;i="5.73,464,1583193600"; d="scan'208";a="47838988" Received: from sea32-co-svc-lb4-vlan2.sea.corp.amazon.com (HELO email-inbound-relay-1d-98acfc19.us-east-1.amazon.com) ([10.47.23.34]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 02 Jun 2020 13:02:57 +0000 Received: from EX13MTAUEA002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1d-98acfc19.us-east-1.amazon.com (Postfix) with ESMTPS id F177BA0814; Tue, 2 Jun 2020 13:02:45 +0000 (UTC) Received: from EX13D31EUA001.ant.amazon.com (10.43.165.15) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:02:45 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.175) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:02:27 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v14 01/15] mm/page_ext: Export lookup_page_ext() to GPL modules Date: Tue, 2 Jun 2020 15:01:11 +0200 Message-ID: <20200602130125.20467-2-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200602130125.20467-1-sjpark@amazon.com> References: <20200602130125.20467-1-sjpark@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.175] X-ClientProxiedBy: EX13D29UWC002.ant.amazon.com (10.43.162.254) To EX13D31EUA001.ant.amazon.com (10.43.165.15) X-Rspamd-Queue-Id: 0F6B738349 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: SeongJae Park This commit exports 'lookup_page_ext()' to GPL modules. This will be used by DAMON. Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster --- mm/page_ext.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/page_ext.c b/mm/page_ext.c index a3616f7a0e9e..9d802d01fcb5 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -131,6 +131,7 @@ struct page_ext *lookup_page_ext(const struct page *page) MAX_ORDER_NR_PAGES); return get_entry(base, index); } +EXPORT_SYMBOL_GPL(lookup_page_ext); static int __init alloc_node_page_ext(int nid) { From patchwork Tue Jun 2 13:01:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11583763 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EFAA660D for ; Tue, 2 Jun 2020 13:04:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AA06520663 for ; Tue, 2 Jun 2020 13:04:02 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Tue, 2 Jun 2020 13:03:05 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.175) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:02:49 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v14 02/15] mm: Introduce Data Access MONitor (DAMON) Date: Tue, 2 Jun 2020 15:01:12 +0200 Message-ID: <20200602130125.20467-3-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200602130125.20467-1-sjpark@amazon.com> References: <20200602130125.20467-1-sjpark@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.175] X-ClientProxiedBy: EX13D29UWC002.ant.amazon.com (10.43.162.254) To EX13D31EUA001.ant.amazon.com (10.43.165.15) X-Rspamd-Queue-Id: 4BAD01FA88 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: SeongJae Park This commit introduces a kernel module named DAMON. Note that this commit is implementing only the stub for the module load/unload, basic data structures, and simple manipulation functions of the structures to keep the size of commit small. The core mechanisms of DAMON will be implemented one by one by following commits. Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster --- include/linux/damon.h | 54 +++++++++++++ mm/Kconfig | 12 +++ mm/Makefile | 1 + mm/damon.c | 173 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 240 insertions(+) create mode 100644 include/linux/damon.h create mode 100644 mm/damon.c diff --git a/include/linux/damon.h b/include/linux/damon.h new file mode 100644 index 000000000000..135633334929 --- /dev/null +++ b/include/linux/damon.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * DAMON api + * + * Copyright 2019-2020 Amazon.com, Inc. or its affiliates. + * + * Author: SeongJae Park + */ + +#ifndef _DAMON_H_ +#define _DAMON_H_ + +#include +#include + +/** + * struct damon_region - Represents a monitoring target region of + * [@vm_start, @vm_end). + * + * @vm_start: Start address of the region (inclusive). + * @vm_end: End address of the region (exclusive). + * @sampling_addr: Address of the sample for the next access check. + * @nr_accesses: Access frequency of this region. + * @list: List head for siblings. + */ +struct damon_region { + unsigned long vm_start; + unsigned long vm_end; + unsigned long sampling_addr; + unsigned int nr_accesses; + struct list_head list; +}; + +/** + * struct damon_task - Represents a monitoring target task. + * @pid: Process id of the task. + * @regions_list: Head of the monitoring target regions of this task. + * @list: List head for siblings. + */ +struct damon_task { + int pid; + struct list_head regions_list; + struct list_head list; +}; + +/** + * struct damon_ctx - Represents a context for each monitoring. + * @tasks_list: Head of monitoring target tasks (&damon_task) list. + */ +struct damon_ctx { + struct list_head tasks_list; /* 'damon_task' objects */ +}; + +#endif diff --git a/mm/Kconfig b/mm/Kconfig index c1acc34c1c35..ecea0889ea35 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -867,4 +867,16 @@ config ARCH_HAS_HUGEPD config MAPPING_DIRTY_HELPERS bool +config DAMON + tristate "Data Access Monitor" + depends on MMU + help + Provides data access monitoring. + + DAMON is a kernel module that allows users to monitor the actual + memory access pattern of specific user-space processes. It aims to + be 1) accurate enough to be useful for performance-centric domains, + and 2) sufficiently light-weight so that it can be applied online. + If unsure, say N. + endmenu diff --git a/mm/Makefile b/mm/Makefile index fccd3756b25f..230e545b6e07 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -112,3 +112,4 @@ obj-$(CONFIG_MEMFD_CREATE) += memfd.o obj-$(CONFIG_MAPPING_DIRTY_HELPERS) += mapping_dirty_helpers.o obj-$(CONFIG_PTDUMP_CORE) += ptdump.o obj-$(CONFIG_PAGE_REPORTING) += page_reporting.o +obj-$(CONFIG_DAMON) += damon.o diff --git a/mm/damon.c b/mm/damon.c new file mode 100644 index 000000000000..a5a7820ef0ad --- /dev/null +++ b/mm/damon.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Data Access Monitor + * + * Copyright 2019-2020 Amazon.com, Inc. or its affiliates. + * + * Author: SeongJae Park + */ + +#define pr_fmt(fmt) "damon: " fmt + +#include +#include +#include +#include + +#define damon_get_task_struct(t) \ + (get_pid_task(find_vpid(t->pid), PIDTYPE_PID)) + +#define damon_next_region(r) \ + (container_of(r->list.next, struct damon_region, list)) + +#define damon_prev_region(r) \ + (container_of(r->list.prev, struct damon_region, list)) + +#define damon_for_each_region(r, t) \ + list_for_each_entry(r, &t->regions_list, list) + +#define damon_for_each_region_safe(r, next, t) \ + list_for_each_entry_safe(r, next, &t->regions_list, list) + +#define damon_for_each_task(t, ctx) \ + list_for_each_entry(t, &(ctx)->tasks_list, list) + +#define damon_for_each_task_safe(t, next, ctx) \ + list_for_each_entry_safe(t, next, &(ctx)->tasks_list, list) + +/* Get a random number in [l, r) */ +#define damon_rand(l, r) (l + prandom_u32() % (r - l)) + +/* + * Construct a damon_region struct + * + * Returns the pointer to the new struct if success, or NULL otherwise + */ +static struct damon_region *damon_new_region(struct damon_ctx *ctx, + unsigned long vm_start, unsigned long vm_end) +{ + struct damon_region *region; + + region = kmalloc(sizeof(*region), GFP_KERNEL); + if (!region) + return NULL; + + region->vm_start = vm_start; + region->vm_end = vm_end; + region->nr_accesses = 0; + INIT_LIST_HEAD(®ion->list); + + return region; +} + +/* + * Add a region between two other regions + */ +static inline void damon_insert_region(struct damon_region *r, + struct damon_region *prev, struct damon_region *next) +{ + __list_add(&r->list, &prev->list, &next->list); +} + +static void damon_add_region(struct damon_region *r, struct damon_task *t) +{ + list_add_tail(&r->list, &t->regions_list); +} + +static void damon_del_region(struct damon_region *r) +{ + list_del(&r->list); +} + +static void damon_free_region(struct damon_region *r) +{ + kfree(r); +} + +static void damon_destroy_region(struct damon_region *r) +{ + damon_del_region(r); + damon_free_region(r); +} + +/* + * Construct a damon_task struct + * + * Returns the pointer to the new struct if success, or NULL otherwise + */ +static struct damon_task *damon_new_task(int pid) +{ + struct damon_task *t; + + t = kmalloc(sizeof(*t), GFP_KERNEL); + if (!t) + return NULL; + + t->pid = pid; + INIT_LIST_HEAD(&t->regions_list); + + return t; +} + +static void damon_add_task(struct damon_ctx *ctx, struct damon_task *t) +{ + list_add_tail(&t->list, &ctx->tasks_list); +} + +static void damon_del_task(struct damon_task *t) +{ + list_del(&t->list); +} + +static void damon_free_task(struct damon_task *t) +{ + struct damon_region *r, *next; + + damon_for_each_region_safe(r, next, t) + damon_free_region(r); + kfree(t); +} + +static void damon_destroy_task(struct damon_task *t) +{ + damon_del_task(t); + damon_free_task(t); +} + +static unsigned int nr_damon_tasks(struct damon_ctx *ctx) +{ + struct damon_task *t; + unsigned int nr_tasks = 0; + + damon_for_each_task(t, ctx) + nr_tasks++; + + return nr_tasks; +} + +static unsigned int nr_damon_regions(struct damon_task *t) +{ + struct damon_region *r; + unsigned int nr_regions = 0; + + damon_for_each_region(r, t) + nr_regions++; + + return nr_regions; +} + +static int __init damon_init(void) +{ + return 0; +} + +static void __exit damon_exit(void) +{ +} + +module_init(damon_init); +module_exit(damon_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("SeongJae Park "); +MODULE_DESCRIPTION("DAMON: Data Access MONitor"); From patchwork Tue Jun 2 13:01:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11583773 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F04A3159A for ; Tue, 2 Jun 2020 13:05:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 998EE206E2 for ; Tue, 2 Jun 2020 13:05:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="Rs9Wvs3/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 998EE206E2 Authentication-Results: mail.kernel.org; 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IronPort-SDR: Wu0jOKNNkbwv7nvLvOUG0rMuh4bHJBmVrD3EZqKRN3f5n8t+aRUp3l99epfTFrhpCkUMgonwCg T3fNvnN+hclQ== X-IronPort-AV: E=Sophos;i="5.73,464,1583193600"; d="scan'208";a="33961348" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1d-9ec21598.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 02 Jun 2020 13:04:22 +0000 Received: from EX13MTAUEA002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1d-9ec21598.us-east-1.amazon.com (Postfix) with ESMTPS id 3DA6AA1AC8; Tue, 2 Jun 2020 13:04:10 +0000 (UTC) Received: from EX13D31EUA001.ant.amazon.com (10.43.165.15) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:04:10 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.175) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:03:54 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v14 03/15] mm/damon: Implement region based sampling Date: Tue, 2 Jun 2020 15:01:13 +0200 Message-ID: <20200602130125.20467-4-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200602130125.20467-1-sjpark@amazon.com> References: <20200602130125.20467-1-sjpark@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.175] X-ClientProxiedBy: EX13D29UWC002.ant.amazon.com (10.43.162.254) To EX13D31EUA001.ant.amazon.com (10.43.165.15) X-Rspamd-Queue-Id: 4AA8D18144D59 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: SeongJae Park This commit implements DAMON's basic access check and region based sampling mechanisms. This change would seems make no sense, mainly because it is only a part of the DAMON's logics. Following two commits will make more sense. Basic Access Check ------------------ DAMON basically reports what pages are how frequently accessed. Note that the frequency is not an absolute number of accesses, but a relative frequency among the pages of the target workloads. Users can control the resolution of the reports by setting two time intervals, ``sampling interval`` and ``aggregation interval``. In detail, DAMON checks access to each page per ``sampling interval``, aggregates the results (counts the number of the accesses to each page), and reports the aggregated results per ``aggregation interval``. For the access check of each page, DAMON uses the Accessed bits of PTEs. This is thus similar to common periodic access checks based access tracking mechanisms, which overhead is increasing as the size of the target process grows. Region Based Sampling --------------------- To avoid the unbounded increase of the overhead, DAMON groups a number of adjacent pages that assumed to have same access frequencies into a region. As long as the assumption (pages in a region have same access frequencies) is kept, only one page in the region is required to be checked. Thus, for each ``sampling interval``, DAMON randomly picks one page in each region and clears its Accessed bit. After one more ``sampling interval``, DAMON reads the Accessed bit of the page and increases the access frequency of the region if the bit has set meanwhile. Therefore, the monitoring overhead is controllable by setting the number of regions. Nonetheless, this scheme cannot preserve the quality of the output if the assumption is not kept. Following commit will introduce how we can make the guarantee with best effort. Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster --- include/linux/damon.h | 48 +++- mm/damon.c | 597 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 644 insertions(+), 1 deletion(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index 135633334929..f0fe4520a4e9 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -11,6 +11,8 @@ #define _DAMON_H_ #include +#include +#include #include /** @@ -44,11 +46,55 @@ struct damon_task { }; /** - * struct damon_ctx - Represents a context for each monitoring. + * struct damon_ctx - Represents a context for each monitoring. This is the + * main interface that allows users to set the attributes and get the results + * of the monitoring. + * + * For each monitoring request (damon_start()), a kernel thread for the + * monitoring is created. The pointer to the thread is stored in @kdamond. + * + * @sample_interval: The time between access samplings. + * @aggr_interval: The time between monitor results aggregations. + * @min_nr_regions: The number of initial monitoring regions. + * + * For each @sample_interval, DAMON checks whether each region is accessed or + * not. It aggregates and keeps the access information (number of accesses to + * each region) for @aggr_interval time. All time intervals are in + * micro-seconds. + * + * @kdamond: Kernel thread who does the monitoring. + * @kdamond_stop: Notifies whether kdamond should stop. + * @kdamond_lock: Mutex for the synchronizations with @kdamond. + * + * The monitoring thread sets @kdamond to NULL when it terminates. Therefore, + * users can know whether the monitoring is ongoing or terminated by reading + * @kdamond. Also, users can ask @kdamond to be terminated by writing non-zero + * to @kdamond_stop. Reads and writes to @kdamond and @kdamond_stop from + * outside of the monitoring thread must be protected by @kdamond_lock. + * + * Note that the monitoring thread protects only @kdamond and @kdamond_stop via + * @kdamond_lock. Accesses to other fields must be protected by themselves. + * * @tasks_list: Head of monitoring target tasks (&damon_task) list. */ struct damon_ctx { + unsigned long sample_interval; + unsigned long aggr_interval; + unsigned long min_nr_regions; + + struct timespec64 last_aggregation; + + struct task_struct *kdamond; + bool kdamond_stop; + struct mutex kdamond_lock; + struct list_head tasks_list; /* 'damon_task' objects */ }; +int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids); +int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, + unsigned long aggr_int, unsigned long min_nr_reg); +int damon_start(struct damon_ctx *ctx); +int damon_stop(struct damon_ctx *ctx); + #endif diff --git a/mm/damon.c b/mm/damon.c index a5a7820ef0ad..b374544cdd78 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -10,10 +10,19 @@ #define pr_fmt(fmt) "damon: " fmt #include +#include +#include #include #include +#include +#include +#include +#include #include +/* Minimal region size. Every damon_region is aligned by this. */ +#define MIN_REGION PAGE_SIZE + #define damon_get_task_struct(t) \ (get_pid_task(find_vpid(t->pid), PIDTYPE_PID)) @@ -156,6 +165,594 @@ static unsigned int nr_damon_regions(struct damon_task *t) return nr_regions; } +/* + * Get the mm_struct of the given task + * + * Caller _must_ put the mm_struct after use, unless it is NULL. + * + * Returns the mm_struct of the task on success, NULL on failure + */ +static struct mm_struct *damon_get_mm(struct damon_task *t) +{ + struct task_struct *task; + struct mm_struct *mm; + + task = damon_get_task_struct(t); + if (!task) + return NULL; + + mm = get_task_mm(task); + put_task_struct(task); + return mm; +} + +/* + * Size-evenly split a region into 'nr_pieces' small regions + * + * Returns 0 on success, or negative error code otherwise. + */ +static int damon_split_region_evenly(struct damon_ctx *ctx, + struct damon_region *r, unsigned int nr_pieces) +{ + unsigned long sz_orig, sz_piece, orig_end; + struct damon_region *n = NULL, *next; + unsigned long start; + + if (!r || !nr_pieces) + return -EINVAL; + + orig_end = r->vm_end; + sz_orig = r->vm_end - r->vm_start; + sz_piece = ALIGN_DOWN(sz_orig / nr_pieces, MIN_REGION); + + if (!sz_piece) + return -EINVAL; + + r->vm_end = r->vm_start + sz_piece; + next = damon_next_region(r); + for (start = r->vm_end; start + sz_piece <= orig_end; + start += sz_piece) { + n = damon_new_region(ctx, start, start + sz_piece); + if (!n) + return -ENOMEM; + damon_insert_region(n, r, next); + r = n; + } + /* complement last region for possible rounding error */ + if (n) + n->vm_end = orig_end; + + return 0; +} + +struct region { + unsigned long start; + unsigned long end; +}; + +static unsigned long sz_region(struct region *r) +{ + return r->end - r->start; +} + +static void swap_regions(struct region *r1, struct region *r2) +{ + struct region tmp; + + tmp = *r1; + *r1 = *r2; + *r2 = tmp; +} + +/* + * Find three regions separated by two biggest unmapped regions + * + * vma the head vma of the target address space + * regions an array of three 'struct region's that results will be saved + * + * This function receives an address space and finds three regions in it which + * separated by the two biggest unmapped regions in the space. Please refer to + * below comments of 'damon_init_regions_of()' function to know why this is + * necessary. + * + * Returns 0 if success, or negative error code otherwise. + */ +static int damon_three_regions_in_vmas(struct vm_area_struct *vma, + struct region regions[3]) +{ + struct region gap = {0}, first_gap = {0}, second_gap = {0}; + struct vm_area_struct *last_vma = NULL; + unsigned long start = 0; + + /* Find two biggest gaps so that first_gap > second_gap > others */ + for (; vma; vma = vma->vm_next) { + if (!last_vma) { + start = vma->vm_start; + last_vma = vma; + continue; + } + gap.start = last_vma->vm_end; + gap.end = vma->vm_start; + if (sz_region(&gap) > sz_region(&second_gap)) { + swap_regions(&gap, &second_gap); + if (sz_region(&second_gap) > sz_region(&first_gap)) + swap_regions(&second_gap, &first_gap); + } + last_vma = vma; + } + + if (!sz_region(&second_gap) || !sz_region(&first_gap)) + return -EINVAL; + + /* Sort the two biggest gaps by address */ + if (first_gap.start > second_gap.start) + swap_regions(&first_gap, &second_gap); + + /* Store the result */ + regions[0].start = ALIGN(start, MIN_REGION); + regions[0].end = ALIGN(first_gap.start, MIN_REGION); + regions[1].start = ALIGN(first_gap.end, MIN_REGION); + regions[1].end = ALIGN(second_gap.start, MIN_REGION); + regions[2].start = ALIGN(second_gap.end, MIN_REGION); + regions[2].end = ALIGN(last_vma->vm_end, MIN_REGION); + + return 0; +} + +/* + * Get the three regions in the given task + * + * Returns 0 on success, negative error code otherwise. + */ +static int damon_three_regions_of(struct damon_task *t, + struct region regions[3]) +{ + struct mm_struct *mm; + int rc; + + mm = damon_get_mm(t); + if (!mm) + return -EINVAL; + + down_read(&mm->mmap_sem); + rc = damon_three_regions_in_vmas(mm->mmap, regions); + up_read(&mm->mmap_sem); + + mmput(mm); + return rc; +} + +/* + * Initialize the monitoring target regions for the given task + * + * t the given target task + * + * Because only a number of small portions of the entire address space + * is actually mapped to the memory and accessed, monitoring the unmapped + * regions is wasteful. That said, because we can deal with small noises, + * tracking every mapping is not strictly required but could even incur a high + * overhead if the mapping frequently changes or the number of mappings is + * high. Nonetheless, this may seems very weird. DAMON's dynamic regions + * adjustment mechanism, which will be implemented with following commit will + * make this more sense. + * + * For the reason, we convert the complex mappings to three distinct regions + * that cover every mapped area of the address space. Also the two gaps + * between the three regions are the two biggest unmapped areas in the given + * address space. In detail, this function first identifies the start and the + * end of the mappings and the two biggest unmapped areas of the address space. + * Then, it constructs the three regions as below: + * + * [mappings[0]->start, big_two_unmapped_areas[0]->start) + * [big_two_unmapped_areas[0]->end, big_two_unmapped_areas[1]->start) + * [big_two_unmapped_areas[1]->end, mappings[nr_mappings - 1]->end) + * + * As usual memory map of processes is as below, the gap between the heap and + * the uppermost mmap()-ed region, and the gap between the lowermost mmap()-ed + * region and the stack will be two biggest unmapped regions. Because these + * gaps are exceptionally huge areas in usual address space, excluding these + * two biggest unmapped regions will be sufficient to make a trade-off. + * + * + * + * + * (other mmap()-ed regions and small unmapped regions) + * + * + * + */ +static void damon_init_regions_of(struct damon_ctx *c, struct damon_task *t) +{ + struct damon_region *r, *m = NULL; + struct region regions[3]; + int i; + + if (damon_three_regions_of(t, regions)) { + pr_err("Failed to get three regions of task %d\n", t->pid); + return; + } + + /* Set the initial three regions of the task */ + for (i = 0; i < 3; i++) { + r = damon_new_region(c, regions[i].start, regions[i].end); + if (!r) { + pr_err("%d'th init region creation failed\n", i); + return; + } + damon_add_region(r, t); + if (i == 1) + m = r; + } + + /* Split the middle region into 'min_nr_regions - 2' regions */ + if (damon_split_region_evenly(c, m, c->min_nr_regions - 2)) + pr_warn("Init middle region failed to be split\n"); +} + +/* Initialize '->regions_list' of every task */ +static void kdamond_init_regions(struct damon_ctx *ctx) +{ + struct damon_task *t; + + damon_for_each_task(t, ctx) + damon_init_regions_of(ctx, t); +} + +static void damon_mkold(struct mm_struct *mm, unsigned long addr) +{ + pte_t *pte = NULL; + pmd_t *pmd = NULL; + spinlock_t *ptl; + + if (follow_pte_pmd(mm, addr, NULL, &pte, &pmd, &ptl)) + return; + + if (pte) { + if (pte_young(*pte)) { + clear_page_idle(pte_page(*pte)); + set_page_young(pte_page(*pte)); + } + *pte = pte_mkold(*pte); + pte_unmap_unlock(pte, ptl); + return; + } + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (pmd_young(*pmd)) { + clear_page_idle(pmd_page(*pmd)); + set_page_young(pmd_page(*pmd)); + } + *pmd = pmd_mkold(*pmd); + spin_unlock(ptl); +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ +} + +static void damon_prepare_access_check(struct damon_ctx *ctx, + struct mm_struct *mm, struct damon_region *r) +{ + r->sampling_addr = damon_rand(r->vm_start, r->vm_end); + + damon_mkold(mm, r->sampling_addr); +} + +static void kdamond_prepare_access_checks(struct damon_ctx *ctx) +{ + struct damon_task *t; + struct mm_struct *mm; + struct damon_region *r; + + damon_for_each_task(t, ctx) { + mm = damon_get_mm(t); + if (!mm) + continue; + damon_for_each_region(r, t) + damon_prepare_access_check(ctx, mm, r); + mmput(mm); + } +} + +static bool damon_young(struct mm_struct *mm, unsigned long addr, + unsigned long *page_sz) +{ + pte_t *pte = NULL; + pmd_t *pmd = NULL; + spinlock_t *ptl; + bool young = false; + + if (follow_pte_pmd(mm, addr, NULL, &pte, &pmd, &ptl)) + return false; + + *page_sz = PAGE_SIZE; + if (pte) { + young = pte_young(*pte); + pte_unmap_unlock(pte, ptl); + return young; + } + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + young = pmd_young(*pmd); + spin_unlock(ptl); + *page_sz = ((1UL) << HPAGE_PMD_SHIFT); +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + + return young; +} + +/* + * Check whether the region was accessed after the last preparation + * + * mm 'mm_struct' for the given virtual address space + * r the region to be checked + */ +static void damon_check_access(struct damon_ctx *ctx, + struct mm_struct *mm, struct damon_region *r) +{ + static struct mm_struct *last_mm; + static unsigned long last_addr; + static unsigned long last_page_sz = PAGE_SIZE; + static bool last_accessed; + + /* If the region is in the last checked page, reuse the result */ + if (mm == last_mm && (ALIGN_DOWN(last_addr, last_page_sz) == + ALIGN_DOWN(r->sampling_addr, last_page_sz))) { + if (last_accessed) + r->nr_accesses++; + return; + } + + last_accessed = damon_young(mm, r->sampling_addr, &last_page_sz); + if (last_accessed) + r->nr_accesses++; + + last_mm = mm; + last_addr = r->sampling_addr; +} + +static void kdamond_check_accesses(struct damon_ctx *ctx) +{ + struct damon_task *t; + struct mm_struct *mm; + struct damon_region *r; + + damon_for_each_task(t, ctx) { + mm = damon_get_mm(t); + if (!mm) + continue; + damon_for_each_region(r, t) + damon_check_access(ctx, mm, r); + mmput(mm); + } +} + +/* + * damon_check_reset_time_interval() - Check if a time interval is elapsed. + * @baseline: the time to check whether the interval has elapsed since + * @interval: the time interval (microseconds) + * + * See whether the given time interval has passed since the given baseline + * time. If so, it also updates the baseline to current time for next check. + * + * Return: true if the time interval has passed, or false otherwise. + */ +static bool damon_check_reset_time_interval(struct timespec64 *baseline, + unsigned long interval) +{ + struct timespec64 now; + + ktime_get_coarse_ts64(&now); + if ((timespec64_to_ns(&now) - timespec64_to_ns(baseline)) < + interval * 1000) + return false; + *baseline = now; + return true; +} + +/* + * Check whether it is time to flush the aggregated information + */ +static bool kdamond_aggregate_interval_passed(struct damon_ctx *ctx) +{ + return damon_check_reset_time_interval(&ctx->last_aggregation, + ctx->aggr_interval); +} + +/* + * Reset the aggregated monitoring results + */ +static void kdamond_reset_aggregated(struct damon_ctx *c) +{ + struct damon_task *t; + struct damon_region *r; + + damon_for_each_task(t, c) { + damon_for_each_region(r, t) + r->nr_accesses = 0; + } +} + +/* + * Check whether current monitoring should be stopped + * + * The monitoring is stopped when either the user requested to stop, or all + * monitoring target tasks are dead. + * + * Returns true if need to stop current monitoring. + */ +static bool kdamond_need_stop(struct damon_ctx *ctx) +{ + struct damon_task *t; + struct task_struct *task; + bool stop; + + mutex_lock(&ctx->kdamond_lock); + stop = ctx->kdamond_stop; + mutex_unlock(&ctx->kdamond_lock); + if (stop) + return true; + + damon_for_each_task(t, ctx) { + task = damon_get_task_struct(t); + if (task) { + put_task_struct(task); + return false; + } + } + + return true; +} + +/* + * The monitoring daemon that runs as a kernel thread + */ +static int kdamond_fn(void *data) +{ + struct damon_ctx *ctx = (struct damon_ctx *)data; + struct damon_task *t; + struct damon_region *r, *next; + + pr_info("kdamond (%d) starts\n", ctx->kdamond->pid); + kdamond_init_regions(ctx); + while (!kdamond_need_stop(ctx)) { + kdamond_prepare_access_checks(ctx); + + usleep_range(ctx->sample_interval, ctx->sample_interval + 1); + + kdamond_check_accesses(ctx); + + if (kdamond_aggregate_interval_passed(ctx)) + kdamond_reset_aggregated(ctx); + + } + damon_for_each_task(t, ctx) { + damon_for_each_region_safe(r, next, t) + damon_destroy_region(r); + } + pr_debug("kdamond (%d) finishes\n", ctx->kdamond->pid); + mutex_lock(&ctx->kdamond_lock); + ctx->kdamond = NULL; + mutex_unlock(&ctx->kdamond_lock); + + do_exit(0); +} + +/* + * Controller functions + */ + +static bool damon_kdamond_running(struct damon_ctx *ctx) +{ + bool running; + + mutex_lock(&ctx->kdamond_lock); + running = ctx->kdamond != NULL; + mutex_unlock(&ctx->kdamond_lock); + + return running; +} + +/** + * damon_start() - Starts monitoring with given context. + * @ctx: monitoring context + * + * Return: 0 on success, negative error code otherwise. + */ +int damon_start(struct damon_ctx *ctx) +{ + int err = -EBUSY; + + mutex_lock(&ctx->kdamond_lock); + if (!ctx->kdamond) { + err = 0; + ctx->kdamond_stop = false; + ctx->kdamond = kthread_run(kdamond_fn, ctx, "kdamond"); + if (IS_ERR(ctx->kdamond)) + err = PTR_ERR(ctx->kdamond); + } + mutex_unlock(&ctx->kdamond_lock); + + return err; +} + +/** + * damon_stop() - Stops monitoring of given context. + * @ctx: monitoring context + * + * Return: 0 on success, negative error code otherwise. + */ +int damon_stop(struct damon_ctx *ctx) +{ + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) { + ctx->kdamond_stop = true; + mutex_unlock(&ctx->kdamond_lock); + while (damon_kdamond_running(ctx)) + usleep_range(ctx->sample_interval, + ctx->sample_interval * 2); + return 0; + } + mutex_unlock(&ctx->kdamond_lock); + + return -EPERM; +} + +/** + * damon_set_pids() - Set monitoring target processes. + * @ctx: monitoring context + * @pids: array of target processes pids + * @nr_pids: number of entries in @pids + * + * This function should not be called while the kdamond is running. + * + * Return: 0 on success, negative error code otherwise. + */ +int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids) +{ + ssize_t i; + struct damon_task *t, *next; + + damon_for_each_task_safe(t, next, ctx) + damon_destroy_task(t); + + for (i = 0; i < nr_pids; i++) { + t = damon_new_task(pids[i]); + if (!t) { + pr_err("Failed to alloc damon_task\n"); + return -ENOMEM; + } + damon_add_task(ctx, t); + } + + return 0; +} + +/** + * damon_set_attrs() - Set attributes for the monitoring. + * @ctx: monitoring context + * @sample_int: time interval between samplings + * @aggr_int: time interval between aggregations + * @min_nr_reg: minimal number of regions + * + * This function should not be called while the kdamond is running. + * Every time interval is in micro-seconds. + * + * Return: 0 on success, negative error code otherwise. + */ +int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, + unsigned long aggr_int, unsigned long min_nr_reg) +{ + if (min_nr_reg < 3) { + pr_err("min_nr_regions (%lu) must be at least 3\n", + min_nr_reg); + return -EINVAL; + } + + ctx->sample_interval = sample_int; + ctx->aggr_interval = aggr_int; + ctx->min_nr_regions = min_nr_reg; + + return 0; +} + static int __init damon_init(void) { return 0; From patchwork Tue Jun 2 13:01:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11583767 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6CC341392 for ; Tue, 2 Jun 2020 13:05:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2C93B2053B for ; Tue, 2 Jun 2020 13:05:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="ib2JslG5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C93B2053B Authentication-Results: mail.kernel.org; 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IronPort-SDR: FQPXU5XBJ7K0vxlllz50C/U4FLxiCEt8dmQpdp5gEBEC04rcdDNIwxIZ1j8uXaYYA2uDNNtg3K alxB+nSqN/5Q== X-IronPort-AV: E=Sophos;i="5.73,464,1583193600"; d="scan'208";a="33961464" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2b-baacba05.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 02 Jun 2020 13:05:05 +0000 Received: from EX13MTAUEA002.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2b-baacba05.us-west-2.amazon.com (Postfix) with ESMTPS id D5571A21ED; Tue, 2 Jun 2020 13:05:01 +0000 (UTC) Received: from EX13D31EUA001.ant.amazon.com (10.43.165.15) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:05:01 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.175) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:04:45 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v14 04/15] mm/damon: Adaptively adjust regions Date: Tue, 2 Jun 2020 15:01:14 +0200 Message-ID: <20200602130125.20467-5-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200602130125.20467-1-sjpark@amazon.com> References: <20200602130125.20467-1-sjpark@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.175] X-ClientProxiedBy: EX13D29UWC002.ant.amazon.com (10.43.162.254) To EX13D31EUA001.ant.amazon.com (10.43.165.15) X-Rspamd-Queue-Id: 88DB11CFDF X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: SeongJae Park At the beginning of the monitoring, DAMON constructs the initial regions by evenly splitting the memory mapped address space of the process into the user-specified minimal number of regions. In this initial state, the assumption of the regions (pages in same region have similar access frequencies) is normally not kept and thus the monitoring quality could be low. To keep the assumption as much as possible, DAMON adaptively merges and splits each region. For each ``aggregation interval``, it compares the access frequencies of adjacent regions and merges those if the frequency difference is small. Then, after it reports and clears the aggregated access frequency of each region, it splits each region into two regions if the total number of regions is smaller than the half of the user-specified maximum number of regions. In this way, DAMON provides its best-effort quality and minimal overhead while keeping the bounds users set for their trade-off. Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster --- include/linux/damon.h | 7 +- mm/damon.c | 174 +++++++++++++++++++++++++++++++++++++++--- 2 files changed, 169 insertions(+), 12 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index f0fe4520a4e9..babdba6b5c47 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -56,6 +56,7 @@ struct damon_task { * @sample_interval: The time between access samplings. * @aggr_interval: The time between monitor results aggregations. * @min_nr_regions: The number of initial monitoring regions. + * @max_nr_regions: The maximum number of monitoring regions. * * For each @sample_interval, DAMON checks whether each region is accessed or * not. It aggregates and keeps the access information (number of accesses to @@ -81,6 +82,7 @@ struct damon_ctx { unsigned long sample_interval; unsigned long aggr_interval; unsigned long min_nr_regions; + unsigned long max_nr_regions; struct timespec64 last_aggregation; @@ -92,8 +94,9 @@ struct damon_ctx { }; int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids); -int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, - unsigned long aggr_int, unsigned long min_nr_reg); +int damon_set_attrs(struct damon_ctx *ctx, + unsigned long sample_int, unsigned long aggr_int, + unsigned long min_nr_reg, unsigned long max_nr_reg); int damon_start(struct damon_ctx *ctx); int damon_stop(struct damon_ctx *ctx); diff --git a/mm/damon.c b/mm/damon.c index b374544cdd78..6b8f038331f5 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -332,9 +332,12 @@ static int damon_three_regions_of(struct damon_task *t, * regions is wasteful. That said, because we can deal with small noises, * tracking every mapping is not strictly required but could even incur a high * overhead if the mapping frequently changes or the number of mappings is - * high. Nonetheless, this may seems very weird. DAMON's dynamic regions - * adjustment mechanism, which will be implemented with following commit will - * make this more sense. + * high. The adaptive regions adjustment mechanism will further help to deal + * with the noise by simply identifying the unmapped areas as a region that + * has no access. Moreover, applying the real mappings that would have many + * unmapped areas inside will make the adaptive mechanism quite complex. That + * said, too huge unmapped areas inside the monitoring target should be removed + * to not take the time for the adaptive mechanism. * * For the reason, we convert the complex mappings to three distinct regions * that cover every mapped area of the address space. Also the two gaps @@ -508,20 +511,25 @@ static void damon_check_access(struct damon_ctx *ctx, last_addr = r->sampling_addr; } -static void kdamond_check_accesses(struct damon_ctx *ctx) +static unsigned int kdamond_check_accesses(struct damon_ctx *ctx) { struct damon_task *t; struct mm_struct *mm; struct damon_region *r; + unsigned int max_nr_accesses = 0; damon_for_each_task(t, ctx) { mm = damon_get_mm(t); if (!mm) continue; - damon_for_each_region(r, t) + damon_for_each_region(r, t) { damon_check_access(ctx, mm, r); + max_nr_accesses = max(r->nr_accesses, max_nr_accesses); + } + mmput(mm); } + return max_nr_accesses; } /* @@ -570,6 +578,141 @@ static void kdamond_reset_aggregated(struct damon_ctx *c) } } +#define sz_damon_region(r) (r->vm_end - r->vm_start) + +/* + * Merge two adjacent regions into one region + */ +static void damon_merge_two_regions(struct damon_region *l, + struct damon_region *r) +{ + l->nr_accesses = (l->nr_accesses * sz_damon_region(l) + + r->nr_accesses * sz_damon_region(r)) / + (sz_damon_region(l) + sz_damon_region(r)); + l->vm_end = r->vm_end; + damon_destroy_region(r); +} + +#define diff_of(a, b) (a > b ? a - b : b - a) + +/* + * Merge adjacent regions having similar access frequencies + * + * t task affected by merge operation + * thres '->nr_accesses' diff threshold for the merge + */ +static void damon_merge_regions_of(struct damon_task *t, unsigned int thres) +{ + struct damon_region *r, *prev = NULL, *next; + + damon_for_each_region_safe(r, next, t) { + if (!prev || prev->vm_end != r->vm_start || + diff_of(prev->nr_accesses, r->nr_accesses) > thres) { + prev = r; + continue; + } + damon_merge_two_regions(prev, r); + } +} + +/* + * Merge adjacent regions having similar access frequencies + * + * threshold '->nr_accesses' diff threshold for the merge + * + * This function merges monitoring target regions which are adjacent and their + * access frequencies are similar. This is for minimizing the monitoring + * overhead under the dynamically changeable access pattern. If a merge was + * unnecessarily made, later 'kdamond_split_regions()' will revert it. + */ +static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold) +{ + struct damon_task *t; + + damon_for_each_task(t, c) + damon_merge_regions_of(t, threshold); +} + +/* + * Split a region in two + * + * r the region to be split + * sz_r size of the first sub-region that will be made + */ +static void damon_split_region_at(struct damon_ctx *ctx, + struct damon_region *r, unsigned long sz_r) +{ + struct damon_region *new; + + new = damon_new_region(ctx, r->vm_start + sz_r, r->vm_end); + r->vm_end = new->vm_start; + + damon_insert_region(new, r, damon_next_region(r)); +} + +/* Split every region in the given task into 'nr_subs' regions */ +static void damon_split_regions_of(struct damon_ctx *ctx, + struct damon_task *t, int nr_subs) +{ + struct damon_region *r, *next; + unsigned long sz_region, sz_sub = 0; + int i; + + damon_for_each_region_safe(r, next, t) { + sz_region = r->vm_end - r->vm_start; + + for (i = 0; i < nr_subs - 1 && + sz_region > 2 * MIN_REGION; i++) { + /* + * Randomly select size of left sub-region to be at + * least 10 percent and at most 90% of original region + */ + sz_sub = ALIGN_DOWN(damon_rand(1, 10) * + sz_region / 10, MIN_REGION); + /* Do not allow blank region */ + if (sz_sub == 0 || sz_sub >= sz_region) + continue; + + damon_split_region_at(ctx, r, sz_sub); + sz_region = sz_sub; + } + } +} + +/* + * splits every target region into two randomly-sized regions + * + * This function splits every target region into two random-sized regions if + * current total number of the regions is equal or smaller than half of the + * user-specified maximum number of regions. This is for maximizing the + * monitoring accuracy under the dynamically changeable access patterns. If a + * split was unnecessarily made, later 'kdamond_merge_regions()' will revert + * it. + */ +static void kdamond_split_regions(struct damon_ctx *ctx) +{ + struct damon_task *t; + unsigned int nr_regions = 0; + static unsigned int last_nr_regions; + int nr_subregions = 2; + + damon_for_each_task(t, ctx) + nr_regions += nr_damon_regions(t); + + if (nr_regions > ctx->max_nr_regions / 2) + return; + + /* If number of regions is not changed, we are maybe in corner case */ + if (last_nr_regions == nr_regions && + nr_regions < ctx->max_nr_regions / 3) + nr_subregions = 3; + + damon_for_each_task(t, ctx) + damon_split_regions_of(ctx, t, nr_subregions); + + last_nr_regions = nr_regions; +} + /* * Check whether current monitoring should be stopped * @@ -609,6 +752,7 @@ static int kdamond_fn(void *data) struct damon_ctx *ctx = (struct damon_ctx *)data; struct damon_task *t; struct damon_region *r, *next; + unsigned int max_nr_accesses = 0; pr_info("kdamond (%d) starts\n", ctx->kdamond->pid); kdamond_init_regions(ctx); @@ -617,11 +761,13 @@ static int kdamond_fn(void *data) usleep_range(ctx->sample_interval, ctx->sample_interval + 1); - kdamond_check_accesses(ctx); + max_nr_accesses = kdamond_check_accesses(ctx); - if (kdamond_aggregate_interval_passed(ctx)) + if (kdamond_aggregate_interval_passed(ctx)) { + kdamond_merge_regions(ctx, max_nr_accesses / 10); kdamond_reset_aggregated(ctx); - + kdamond_split_regions(ctx); + } } damon_for_each_task(t, ctx) { damon_for_each_region_safe(r, next, t) @@ -731,24 +877,32 @@ int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids) * @sample_int: time interval between samplings * @aggr_int: time interval between aggregations * @min_nr_reg: minimal number of regions + * @max_nr_reg: maximum number of regions * * This function should not be called while the kdamond is running. * Every time interval is in micro-seconds. * * Return: 0 on success, negative error code otherwise. */ -int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, - unsigned long aggr_int, unsigned long min_nr_reg) +int damon_set_attrs(struct damon_ctx *ctx, + unsigned long sample_int, unsigned long aggr_int, + unsigned long min_nr_reg, unsigned long max_nr_reg) { if (min_nr_reg < 3) { pr_err("min_nr_regions (%lu) must be at least 3\n", min_nr_reg); return -EINVAL; } + if (min_nr_reg > max_nr_reg) { + pr_err("invalid nr_regions. min (%lu) > max (%lu)\n", + min_nr_reg, max_nr_reg); + return -EINVAL; + } ctx->sample_interval = sample_int; ctx->aggr_interval = aggr_int; ctx->min_nr_regions = min_nr_reg; + ctx->max_nr_regions = max_nr_reg; return 0; } From patchwork Tue Jun 2 13:01:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11583787 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 10F4313B6 for ; Tue, 2 Jun 2020 13:07:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C493D20674 for ; Tue, 2 Jun 2020 13:07:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="Ec72iqan" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C493D20674 Authentication-Results: mail.kernel.org; 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IronPort-SDR: Dqp/Rmb1L0tSqGZht+EJttCRAW/CDi3LUhveVa9C1NFWUU70m6gEaLZJu2BM6sjITd3E0SbyHo xxyqw9b5z+eA== X-IronPort-AV: E=Sophos;i="5.73,464,1583193600"; d="scan'208";a="47839751" Received: from sea32-co-svc-lb4-vlan2.sea.corp.amazon.com (HELO email-inbound-relay-2b-4ff6265a.us-west-2.amazon.com) ([10.47.23.34]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 02 Jun 2020 13:06:05 +0000 Received: from EX13MTAUEA002.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan3.pdx.amazon.com [10.170.41.166]) by email-inbound-relay-2b-4ff6265a.us-west-2.amazon.com (Postfix) with ESMTPS id EB7D8A27E4; Tue, 2 Jun 2020 13:06:02 +0000 (UTC) Received: from EX13D31EUA001.ant.amazon.com (10.43.165.15) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:06:02 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.175) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:05:46 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v14 05/15] mm/damon: Apply dynamic memory mapping changes Date: Tue, 2 Jun 2020 15:01:15 +0200 Message-ID: <20200602130125.20467-6-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200602130125.20467-1-sjpark@amazon.com> References: <20200602130125.20467-1-sjpark@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.175] X-ClientProxiedBy: EX13D29UWC002.ant.amazon.com (10.43.162.254) To EX13D31EUA001.ant.amazon.com (10.43.165.15) X-Rspamd-Queue-Id: ACD581698E7 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: SeongJae Park Only a number of parts in the virtual address space of the processes is mapped to physical memory and accessed. Thus, tracking the unmapped address regions is just wasteful. However, tracking every memory mapping change might incur an overhead. For the reason, DAMON applies the dynamic memory mapping changes to the tracking regions only for each of a user-specified time interval (``regions update interval``). Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster --- include/linux/damon.h | 13 ++++-- mm/damon.c | 101 +++++++++++++++++++++++++++++++++++++++++- 2 files changed, 108 insertions(+), 6 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index babdba6b5c47..5afcb2bb7f77 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -55,13 +55,16 @@ struct damon_task { * * @sample_interval: The time between access samplings. * @aggr_interval: The time between monitor results aggregations. + * @regions_update_interval: The time between monitor regions updates. * @min_nr_regions: The number of initial monitoring regions. * @max_nr_regions: The maximum number of monitoring regions. * * For each @sample_interval, DAMON checks whether each region is accessed or * not. It aggregates and keeps the access information (number of accesses to - * each region) for @aggr_interval time. All time intervals are in - * micro-seconds. + * each region) for @aggr_interval time. DAMON also checks whether the target + * memory regions need update (e.g., by ``mmap()`` calls from the application, + * in case of virtual memory monitoring) and applies the changes for each + * @regions_update_interval. All time intervals are in micro-seconds. * * @kdamond: Kernel thread who does the monitoring. * @kdamond_stop: Notifies whether kdamond should stop. @@ -81,10 +84,12 @@ struct damon_task { struct damon_ctx { unsigned long sample_interval; unsigned long aggr_interval; + unsigned long regions_update_interval; unsigned long min_nr_regions; unsigned long max_nr_regions; struct timespec64 last_aggregation; + struct timespec64 last_regions_update; struct task_struct *kdamond; bool kdamond_stop; @@ -94,8 +99,8 @@ struct damon_ctx { }; int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids); -int damon_set_attrs(struct damon_ctx *ctx, - unsigned long sample_int, unsigned long aggr_int, +int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, + unsigned long aggr_int, unsigned long regions_update_int, unsigned long min_nr_reg, unsigned long max_nr_reg); int damon_start(struct damon_ctx *ctx); int damon_stop(struct damon_ctx *ctx); diff --git a/mm/damon.c b/mm/damon.c index 6b8f038331f5..de5ed38ac05c 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -713,6 +713,98 @@ static void kdamond_split_regions(struct damon_ctx *ctx) last_nr_regions = nr_regions; } +/* + * Check whether it is time to check and apply the dynamic mmap changes + * + * Returns true if it is. + */ +static bool kdamond_need_update_regions(struct damon_ctx *ctx) +{ + return damon_check_reset_time_interval(&ctx->last_regions_update, + ctx->regions_update_interval); +} + +/* + * Check whether regions are intersecting + * + * Note that this function checks 'struct damon_region' and 'struct region'. + * + * Returns true if it is. + */ +static bool damon_intersect(struct damon_region *r, struct region *re) +{ + return !(r->vm_end <= re->start || re->end <= r->vm_start); +} + +/* + * Update damon regions for the three big regions of the given task + * + * t the given task + * bregions the three big regions of the task + */ +static void damon_apply_three_regions(struct damon_ctx *ctx, + struct damon_task *t, struct region bregions[3]) +{ + struct damon_region *r, *next; + unsigned int i = 0; + + /* Remove regions which are not in the three big regions now */ + damon_for_each_region_safe(r, next, t) { + for (i = 0; i < 3; i++) { + if (damon_intersect(r, &bregions[i])) + break; + } + if (i == 3) + damon_destroy_region(r); + } + + /* Adjust intersecting regions to fit with the three big regions */ + for (i = 0; i < 3; i++) { + struct damon_region *first = NULL, *last; + struct damon_region *newr; + struct region *br; + + br = &bregions[i]; + /* Get the first and last regions which intersects with br */ + damon_for_each_region(r, t) { + if (damon_intersect(r, br)) { + if (!first) + first = r; + last = r; + } + if (r->vm_start >= br->end) + break; + } + if (!first) { + /* no damon_region intersects with this big region */ + newr = damon_new_region(ctx, + ALIGN_DOWN(br->start, MIN_REGION), + ALIGN(br->end, MIN_REGION)); + if (!newr) + continue; + damon_insert_region(newr, damon_prev_region(r), r); + } else { + first->vm_start = ALIGN_DOWN(br->start, MIN_REGION); + last->vm_end = ALIGN(br->end, MIN_REGION); + } + } +} + +/* + * Update regions for current memory mappings + */ +static void kdamond_update_regions(struct damon_ctx *ctx) +{ + struct region three_regions[3]; + struct damon_task *t; + + damon_for_each_task(t, ctx) { + if (damon_three_regions_of(t, three_regions)) + continue; + damon_apply_three_regions(ctx, t, three_regions); + } +} + /* * Check whether current monitoring should be stopped * @@ -768,6 +860,9 @@ static int kdamond_fn(void *data) kdamond_reset_aggregated(ctx); kdamond_split_regions(ctx); } + + if (kdamond_need_update_regions(ctx)) + kdamond_update_regions(ctx); } damon_for_each_task(t, ctx) { damon_for_each_region_safe(r, next, t) @@ -875,6 +970,7 @@ int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids) * damon_set_attrs() - Set attributes for the monitoring. * @ctx: monitoring context * @sample_int: time interval between samplings + * @regions_update_int: time interval between vma update checks * @aggr_int: time interval between aggregations * @min_nr_reg: minimal number of regions * @max_nr_reg: maximum number of regions @@ -884,8 +980,8 @@ int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids) * * Return: 0 on success, negative error code otherwise. */ -int damon_set_attrs(struct damon_ctx *ctx, - unsigned long sample_int, unsigned long aggr_int, +int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, + unsigned long aggr_int, unsigned long regions_update_int, unsigned long min_nr_reg, unsigned long max_nr_reg) { if (min_nr_reg < 3) { @@ -901,6 +997,7 @@ int damon_set_attrs(struct damon_ctx *ctx, ctx->sample_interval = sample_int; ctx->aggr_interval = aggr_int; + ctx->regions_update_interval = regions_update_int; ctx->min_nr_regions = min_nr_reg; ctx->max_nr_regions = max_nr_reg; From patchwork Tue Jun 2 13:01:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11583783 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9FF3213B6 for ; Tue, 2 Jun 2020 13:07:14 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6C38720674 for ; Tue, 2 Jun 2020 13:07:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="TqNlHCve" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C38720674 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; 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Using this, DAMON users can install their callbacks for each step of the access monitoring so that they can do something interesting with the monitored access patterns online. For example, callbacks can report the monitored patterns to users or do some access pattern based memory management such as proactive reclamations or access pattern based THP promotions/demotions decision makings. Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster --- include/linux/damon.h | 13 +++++++++++++ mm/damon.c | 4 ++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/damon.h b/include/linux/damon.h index 5afcb2bb7f77..12536d9d2f74 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -80,6 +80,15 @@ struct damon_task { * @kdamond_lock. Accesses to other fields must be protected by themselves. * * @tasks_list: Head of monitoring target tasks (&damon_task) list. + * + * @sample_cb: Called for each sampling interval. + * @aggregate_cb: Called for each aggregation interval. + * + * @sample_cb and @aggregate_cb are called from @kdamond for each of the + * sampling intervals and aggregation intervals, respectively. Therefore, + * users can safely access to the monitoring results via @tasks_list without + * additional protection of @kdamond_lock. For the reason, users are + * recommended to use these callback for the accesses to the results. */ struct damon_ctx { unsigned long sample_interval; @@ -96,6 +105,10 @@ struct damon_ctx { struct mutex kdamond_lock; struct list_head tasks_list; /* 'damon_task' objects */ + + /* callbacks */ + void (*sample_cb)(struct damon_ctx *context); + void (*aggregate_cb)(struct damon_ctx *context); }; int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids); diff --git a/mm/damon.c b/mm/damon.c index de5ed38ac05c..42ce9df47f8b 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -850,6 +850,8 @@ static int kdamond_fn(void *data) kdamond_init_regions(ctx); while (!kdamond_need_stop(ctx)) { kdamond_prepare_access_checks(ctx); + if (ctx->sample_cb) + ctx->sample_cb(ctx); usleep_range(ctx->sample_interval, ctx->sample_interval + 1); @@ -857,6 +859,8 @@ static int kdamond_fn(void *data) if (kdamond_aggregate_interval_passed(ctx)) { kdamond_merge_regions(ctx, max_nr_accesses / 10); + if (ctx->aggregate_cb) + ctx->aggregate_cb(ctx); kdamond_reset_aggregated(ctx); kdamond_split_regions(ctx); } From patchwork Tue Jun 2 13:01:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 11583797 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CF7D513B6 for ; Tue, 2 Jun 2020 13:08:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8F57B20674 for ; Tue, 2 Jun 2020 13:08:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="N1HfaJTu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F57B20674 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B5E1A28007E; 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IronPort-SDR: BGM9BoaSXT4d86sKHbUY2ReEYK73L0zuEP6m5p8hPjO42ov3afVzkj3w/qttteGSyWgwOjuC36 zmHd3f2Q6beQ== X-IronPort-AV: E=Sophos;i="5.73,464,1583193600"; d="scan'208";a="47840163" Received: from sea32-co-svc-lb4-vlan2.sea.corp.amazon.com (HELO email-inbound-relay-2c-87a10be6.us-west-2.amazon.com) ([10.47.23.34]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 02 Jun 2020 13:08:01 +0000 Received: from EX13MTAUEA002.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2c-87a10be6.us-west-2.amazon.com (Postfix) with ESMTPS id 1BDF6A1EC7; Tue, 2 Jun 2020 13:07:59 +0000 (UTC) Received: from EX13D31EUA001.ant.amazon.com (10.43.165.15) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:07:58 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.175) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 13:07:42 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v14 07/15] mm/damon: Implement access pattern recording Date: Tue, 2 Jun 2020 15:01:17 +0200 Message-ID: <20200602130125.20467-8-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200602130125.20467-1-sjpark@amazon.com> References: <20200602130125.20467-1-sjpark@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.175] X-ClientProxiedBy: EX13D29UWC002.ant.amazon.com (10.43.162.254) To EX13D31EUA001.ant.amazon.com (10.43.165.15) X-Rspamd-Queue-Id: 2368410F5F X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: SeongJae Park This commit implements the recording feature of DAMON. If this feature is enabled, DAMON writes the monitored access patterns in its binary format into a file which specified by the user. This is already able to be implemented by each user using the callbacks. However, as the recording is expected to be used widely, this commit implements the feature in the DAMON, for more convenience and efficiency. Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster --- include/linux/damon.h | 15 +++++ mm/damon.c | 131 +++++++++++++++++++++++++++++++++++++++++- 2 files changed, 143 insertions(+), 3 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index 12536d9d2f74..c4796a10cb1a 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -66,6 +66,14 @@ struct damon_task { * in case of virtual memory monitoring) and applies the changes for each * @regions_update_interval. All time intervals are in micro-seconds. * + * @rbuf: In-memory buffer for monitoring result recording. + * @rbuf_len: The length of @rbuf. + * @rbuf_offset: The offset for next write to @rbuf. + * @rfile_path: Record file path. + * + * If @rbuf, @rbuf_len, and @rfile_path are set, the monitored results are + * automatically stored in @rfile_path file. + * * @kdamond: Kernel thread who does the monitoring. * @kdamond_stop: Notifies whether kdamond should stop. * @kdamond_lock: Mutex for the synchronizations with @kdamond. @@ -100,6 +108,11 @@ struct damon_ctx { struct timespec64 last_aggregation; struct timespec64 last_regions_update; + unsigned char *rbuf; + unsigned int rbuf_len; + unsigned int rbuf_offset; + char *rfile_path; + struct task_struct *kdamond; bool kdamond_stop; struct mutex kdamond_lock; @@ -115,6 +128,8 @@ int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids); int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, unsigned long aggr_int, unsigned long regions_update_int, unsigned long min_nr_reg, unsigned long max_nr_reg); +int damon_set_recording(struct damon_ctx *ctx, + unsigned int rbuf_len, char *rfile_path); int damon_start(struct damon_ctx *ctx); int damon_stop(struct damon_ctx *ctx); diff --git a/mm/damon.c b/mm/damon.c index 42ce9df47f8b..768ffd08f7ab 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -44,6 +44,9 @@ #define damon_for_each_task_safe(t, next, ctx) \ list_for_each_entry_safe(t, next, &(ctx)->tasks_list, list) +#define MAX_RECORD_BUFFER_LEN (4 * 1024 * 1024) +#define MAX_RFILE_PATH_LEN 256 + /* Get a random number in [l, r) */ #define damon_rand(l, r) (l + prandom_u32() % (r - l)) @@ -565,16 +568,80 @@ static bool kdamond_aggregate_interval_passed(struct damon_ctx *ctx) } /* - * Reset the aggregated monitoring results + * Flush the content in the result buffer to the result file + */ +static void damon_flush_rbuffer(struct damon_ctx *ctx) +{ + ssize_t sz; + loff_t pos = 0; + struct file *rfile; + + rfile = filp_open(ctx->rfile_path, O_CREAT | O_RDWR | O_APPEND, 0644); + if (IS_ERR(rfile)) { + pr_err("Cannot open the result file %s\n", + ctx->rfile_path); + return; + } + + while (ctx->rbuf_offset) { + sz = kernel_write(rfile, ctx->rbuf, ctx->rbuf_offset, &pos); + if (sz < 0) + break; + ctx->rbuf_offset -= sz; + } + filp_close(rfile, NULL); +} + +/* + * Write a data into the result buffer + */ +static void damon_write_rbuf(struct damon_ctx *ctx, void *data, ssize_t size) +{ + if (!ctx->rbuf_len || !ctx->rbuf) + return; + if (ctx->rbuf_offset + size > ctx->rbuf_len) + damon_flush_rbuffer(ctx); + + memcpy(&ctx->rbuf[ctx->rbuf_offset], data, size); + ctx->rbuf_offset += size; +} + +/* + * Flush the aggregated monitoring results to the result buffer + * + * Stores current tracking results to the result buffer and reset 'nr_accesses' + * of each region. The format for the result buffer is as below: + * + *