From patchwork Wed Sep 8 02:56:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12479917 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 851E1C433EF for ; Wed, 8 Sep 2021 02:56:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3A76E60E52 for ; Wed, 8 Sep 2021 02:56:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3A76E60E52 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D17A3940016; Tue, 7 Sep 2021 22:56:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CC571900003; Tue, 7 Sep 2021 22:56:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B8CD0940016; Tue, 7 Sep 2021 22:56:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0077.hostedemail.com [216.40.44.77]) by kanga.kvack.org (Postfix) with ESMTP id A4818900003 for ; Tue, 7 Sep 2021 22:56:35 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 683762D244 for ; Wed, 8 Sep 2021 02:56:35 +0000 (UTC) X-FDA: 78562893150.03.291C902 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf08.hostedemail.com (Postfix) with ESMTP id EE0743000098 for ; Wed, 8 Sep 2021 02:56:34 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 3F7D261131; Wed, 8 Sep 2021 02:56:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1631069794; bh=3lXrYTXmm+ZouijOQP8TQD1hebYHYJ6IT4wAQ1cf8Jo=; h=Date:From:To:Subject:In-Reply-To:From; b=SQCA1bOEIy2shVyGpO8EqqLZt6nDfwiUY9Ozi4XT2jYMAaQxMOGYmxbWT/Jnyc5vV f+40jBqBri8GpnwkgJQOJzyCp5H5UBaiidduuuUC67QSjtzj8N3OrUMsirLjfyi8dd 8Ak7ZEIx6wIRANr/gDoZmfsZKuRjTcQcLBldXgfc= Date: Tue, 07 Sep 2021 19:56:32 -0700 From: Andrew Morton To: akpm@linux-foundation.org, alexander.shishkin@linux.intel.com, amit@kernel.org, benh@kernel.crashing.org, brendanhiggins@google.com, corbet@lwn.net, david@redhat.com, dwmw@amazon.com, elver@google.com, fan.du@intel.com, foersleo@amazon.de, greg@kroah.com, gthelen@google.com, joe@perches.com, Jonathan.Cameron@huawei.com, linux-mm@kvack.org, markubo@amazon.de, mgorman@suse.de, mheyne@amazon.de, minchan@kernel.org, mingo@redhat.com, mm-commits@vger.kernel.org, namhyung@kernel.org, peterz@infradead.org, riel@surriel.com, rientjes@google.com, rostedt@goodmis.org, shakeelb@google.com, shuah@kernel.org, sieberf@amazon.com, sjpark@amazon.de, torvalds@linux-foundation.org, vbabka@suse.cz, vdavydov.dev@gmail.com Subject: [patch 064/147] mm/damon/core: implement region-based sampling Message-ID: <20210908025632.BLOJIz5mr%akpm@linux-foundation.org> In-Reply-To: <20210907195226.14b1d22a07c085b22968b933@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=SQCA1bOE; dmarc=none; spf=pass (imf08.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: EE0743000098 X-Stat-Signature: heioeihyenrdnk9fbp9ci71f39mskdri X-HE-Tag: 1631069794-23230 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 Subject: mm/damon/core: implement region-based sampling To avoid the unbounded increase of the overhead, DAMON groups adjacent pages that are assumed to have the same access frequencies into a region. As long as the assumption (pages in a region have the same access frequencies) is kept, only one page in the region is required to be checked. Thus, for each ``sampling interval``, 1. the 'prepare_access_checks' primitive picks one page in each region, 2. waits for one ``sampling interval``, 3. checks whether the page is accessed meanwhile, and 4. increases the access count of the region if so. Therefore, the monitoring overhead is controllable by adjusting the number of regions. DAMON allows both the underlying primitives and user callbacks to adjust regions for the trade-off. In other words, this commit makes DAMON to use not only time-based sampling but also space-based sampling. This scheme, however, cannot preserve the quality of the output if the assumption is not guaranteed. Next commit will address this problem. Link: https://lkml.kernel.org/r/20210716081449.22187-3-sj38.park@gmail.com Signed-off-by: SeongJae Park Reviewed-by: Leonard Foerster Reviewed-by: Fernand Sieber Acked-by: Shakeel Butt Cc: Alexander Shishkin Cc: Amit Shah Cc: Benjamin Herrenschmidt Cc: Brendan Higgins Cc: David Hildenbrand Cc: David Rientjes Cc: David Woodhouse Cc: Fan Du Cc: Greg Kroah-Hartman Cc: Greg Thelen Cc: Ingo Molnar Cc: Joe Perches Cc: Jonathan Cameron Cc: Jonathan Corbet Cc: Marco Elver Cc: Markus Boehme Cc: Maximilian Heyne Cc: Mel Gorman Cc: Minchan Kim Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rik van Riel Cc: Shuah Khan Cc: Steven Rostedt (VMware) Cc: Vladimir Davydov Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- include/linux/damon.h | 77 ++++++++++++++++++++- mm/damon/core.c | 143 ++++++++++++++++++++++++++++++++++++++-- 2 files changed, 213 insertions(+), 7 deletions(-) --- a/include/linux/damon.h~mm-damon-core-implement-region-based-sampling +++ a/include/linux/damon.h @@ -12,6 +12,48 @@ #include #include +/** + * struct damon_addr_range - Represents an address region of [@start, @end). + * @start: Start address of the region (inclusive). + * @end: End address of the region (exclusive). + */ +struct damon_addr_range { + unsigned long start; + unsigned long end; +}; + +/** + * struct damon_region - Represents a monitoring target region. + * @ar: The address range of the region. + * @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 { + struct damon_addr_range ar; + unsigned long sampling_addr; + unsigned int nr_accesses; + struct list_head list; +}; + +/** + * struct damon_target - Represents a monitoring target. + * @id: Unique identifier for this target. + * @regions_list: Head of the monitoring target regions of this target. + * @list: List head for siblings. + * + * Each monitoring context could have multiple targets. For example, a context + * for virtual memory address spaces could have multiple target processes. The + * @id of each target should be unique among the targets of the context. For + * example, in the virtual address monitoring context, it could be a pidfd or + * an address of an mm_struct. + */ +struct damon_target { + unsigned long id; + struct list_head regions_list; + struct list_head list; +}; + struct damon_ctx; /** @@ -36,7 +78,7 @@ struct damon_ctx; * * @init should initialize primitive-internal data structures. For example, * this could be used to construct proper monitoring target regions and link - * those to @damon_ctx.target. + * those to @damon_ctx.adaptive_targets. * @update should update the primitive-internal data structures. For example, * this could be used to update monitoring target regions for current status. * @prepare_access_checks should manipulate the monitoring regions to be @@ -130,7 +172,7 @@ struct damon_callback { * @primitive: Set of monitoring primitives for given use cases. * @callback: Set of callbacks for monitoring events notifications. * - * @target: Pointer to the user-defined monitoring target. + * @region_targets: Head of monitoring targets (&damon_target) list. */ struct damon_ctx { unsigned long sample_interval; @@ -149,11 +191,40 @@ struct damon_ctx { struct damon_primitive primitive; struct damon_callback callback; - void *target; + struct list_head region_targets; }; +#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_target(t, ctx) \ + list_for_each_entry(t, &(ctx)->region_targets, list) + +#define damon_for_each_target_safe(t, next, ctx) \ + list_for_each_entry_safe(t, next, &(ctx)->region_targets, list) + #ifdef CONFIG_DAMON +struct damon_region *damon_new_region(unsigned long start, unsigned long end); +inline void damon_insert_region(struct damon_region *r, + struct damon_region *prev, struct damon_region *next); +void damon_add_region(struct damon_region *r, struct damon_target *t); +void damon_destroy_region(struct damon_region *r); + +struct damon_target *damon_new_target(unsigned long id); +void damon_add_target(struct damon_ctx *ctx, struct damon_target *t); +void damon_free_target(struct damon_target *t); +void damon_destroy_target(struct damon_target *t); + struct damon_ctx *damon_new_ctx(void); void damon_destroy_ctx(struct damon_ctx *ctx); int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, --- a/mm/damon/core.c~mm-damon-core-implement-region-based-sampling +++ a/mm/damon/core.c @@ -15,6 +15,101 @@ static DEFINE_MUTEX(damon_lock); static int nr_running_ctxs; +/* + * Construct a damon_region struct + * + * Returns the pointer to the new struct if success, or NULL otherwise + */ +struct damon_region *damon_new_region(unsigned long start, unsigned long end) +{ + struct damon_region *region; + + region = kmalloc(sizeof(*region), GFP_KERNEL); + if (!region) + return NULL; + + region->ar.start = start; + region->ar.end = end; + region->nr_accesses = 0; + INIT_LIST_HEAD(®ion->list); + + return region; +} + +/* + * Add a region between two other regions + */ +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); +} + +void damon_add_region(struct damon_region *r, struct damon_target *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); +} + +void damon_destroy_region(struct damon_region *r) +{ + damon_del_region(r); + damon_free_region(r); +} + +/* + * Construct a damon_target struct + * + * Returns the pointer to the new struct if success, or NULL otherwise + */ +struct damon_target *damon_new_target(unsigned long id) +{ + struct damon_target *t; + + t = kmalloc(sizeof(*t), GFP_KERNEL); + if (!t) + return NULL; + + t->id = id; + INIT_LIST_HEAD(&t->regions_list); + + return t; +} + +void damon_add_target(struct damon_ctx *ctx, struct damon_target *t) +{ + list_add_tail(&t->list, &ctx->region_targets); +} + +static void damon_del_target(struct damon_target *t) +{ + list_del(&t->list); +} + +void damon_free_target(struct damon_target *t) +{ + struct damon_region *r, *next; + + damon_for_each_region_safe(r, next, t) + damon_free_region(r); + kfree(t); +} + +void damon_destroy_target(struct damon_target *t) +{ + damon_del_target(t); + damon_free_target(t); +} + struct damon_ctx *damon_new_ctx(void) { struct damon_ctx *ctx; @@ -32,15 +127,27 @@ struct damon_ctx *damon_new_ctx(void) mutex_init(&ctx->kdamond_lock); - ctx->target = NULL; + INIT_LIST_HEAD(&ctx->region_targets); return ctx; } -void damon_destroy_ctx(struct damon_ctx *ctx) +static void damon_destroy_targets(struct damon_ctx *ctx) { - if (ctx->primitive.cleanup) + struct damon_target *t, *next_t; + + if (ctx->primitive.cleanup) { ctx->primitive.cleanup(ctx); + return; + } + + damon_for_each_target_safe(t, next_t, ctx) + damon_destroy_target(t); +} + +void damon_destroy_ctx(struct damon_ctx *ctx) +{ + damon_destroy_targets(ctx); kfree(ctx); } @@ -218,6 +325,21 @@ static bool kdamond_aggregate_interval_p } /* + * Reset the aggregated monitoring results ('nr_accesses' of each region). + */ +static void kdamond_reset_aggregated(struct damon_ctx *c) +{ + struct damon_target *t; + + damon_for_each_target(t, c) { + struct damon_region *r; + + damon_for_each_region(r, t) + r->nr_accesses = 0; + } +} + +/* * Check whether it is time to check and apply the target monitoring regions * * Returns true if it is. @@ -238,6 +360,7 @@ static bool kdamond_need_update_primitiv */ static bool kdamond_need_stop(struct damon_ctx *ctx) { + struct damon_target *t; bool stop; mutex_lock(&ctx->kdamond_lock); @@ -249,7 +372,12 @@ static bool kdamond_need_stop(struct dam if (!ctx->primitive.target_valid) return false; - return !ctx->primitive.target_valid(ctx->target); + damon_for_each_target(t, ctx) { + if (ctx->primitive.target_valid(t)) + return false; + } + + return true; } static void set_kdamond_stop(struct damon_ctx *ctx) @@ -265,6 +393,8 @@ static void set_kdamond_stop(struct damo static int kdamond_fn(void *data) { struct damon_ctx *ctx = (struct damon_ctx *)data; + struct damon_target *t; + struct damon_region *r, *next; mutex_lock(&ctx->kdamond_lock); pr_info("kdamond (%d) starts\n", ctx->kdamond->pid); @@ -291,6 +421,7 @@ static int kdamond_fn(void *data) if (ctx->callback.after_aggregation && ctx->callback.after_aggregation(ctx)) set_kdamond_stop(ctx); + kdamond_reset_aggregated(ctx); if (ctx->primitive.reset_aggregated) ctx->primitive.reset_aggregated(ctx); } @@ -300,6 +431,10 @@ static int kdamond_fn(void *data) ctx->primitive.update(ctx); } } + damon_for_each_target(t, ctx) { + damon_for_each_region_safe(r, next, t) + damon_destroy_region(r); + } if (ctx->callback.before_terminate && ctx->callback.before_terminate(ctx))