From patchwork Fri Nov 5 20:47:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12605897 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE282C433F5 for ; Fri, 5 Nov 2021 20:47:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7A73360E94 for ; Fri, 5 Nov 2021 20:47:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7A73360E94 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 16DAF9400F2; Fri, 5 Nov 2021 16:47:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 11C7E9400EF; Fri, 5 Nov 2021 16:47:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0336A9400F2; Fri, 5 Nov 2021 16:47:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0216.hostedemail.com [216.40.44.216]) by kanga.kvack.org (Postfix) with ESMTP id E7F3F9400EF for ; Fri, 5 Nov 2021 16:47:49 -0400 (EDT) Received: from smtpin35.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A8A23779A5 for ; Fri, 5 Nov 2021 20:47:49 +0000 (UTC) X-FDA: 78776063058.35.085A9F4 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf27.hostedemail.com (Postfix) with ESMTP id 2EA0E70000AB for ; Fri, 5 Nov 2021 20:47:49 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id EA7B560174; Fri, 5 Nov 2021 20:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1636145268; bh=I7Mr47Thoczs1zhINP/24nEapbVQXKgGH0IYKoruAcc=; h=Date:From:To:Subject:In-Reply-To:From; b=ci4IDlebwPNo8mJnfa7YyllRtXjBeVfB5IA4lxpcOKXb9ow3yCtapCPzTFoCwR9ZQ EDHngqhRkKaeyU2A/Uy0v+3EofE2RinXjbkWKoSUbHytdiaCu3vVUAyJndZ5hzGhJ5 qf0ALmtDXtrLVeloXwu3pORbAXGKXT3gbYTNa44k= Date: Fri, 05 Nov 2021 13:47:47 -0700 From: Andrew Morton To: akpm@linux-foundation.org, amit@kernel.org, benh@kernel.crashing.org, corbet@lwn.net, david@redhat.com, dwmw@amazon.com, elver@google.com, foersleo@amazon.de, gthelen@google.com, Jonathan.Cameron@huawei.com, linux-mm@kvack.org, markubo@amazon.de, mm-commits@vger.kernel.org, rientjes@google.com, shakeelb@google.com, shuah@kernel.org, sj@kernel.org, torvalds@linux-foundation.org Subject: [patch 249/262] mm/damon/schemes: activate schemes based on a watermarks mechanism Message-ID: <20211105204747.cqLATVL8w%akpm@linux-foundation.org> In-Reply-To: <20211105133408.cccbb98b71a77d5e8430aba1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 2EA0E70000AB X-Stat-Signature: qmzgztgx1zu3kifhz7nns9eaprmwj1yb Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=ci4IDleb; spf=pass (imf27.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-HE-Tag: 1636145269-556700 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/schemes: activate schemes based on a watermarks mechanism DAMON-based operation schemes need to be manually turned on and off. In some use cases, however, the condition for turning a scheme on and off would depend on the system's situation. For example, schemes for proactive pages reclamation would need to be turned on when some memory pressure is detected, and turned off when the system has enough free memory. For easier control of schemes activation based on the system situation, this commit introduces a watermarks-based mechanism. The client can describe the watermark metric (e.g., amount of free memory in the system), watermark check interval, and three watermarks, namely high, mid, and low. If the scheme is deactivated, it only gets the metric and compare that to the three watermarks for every check interval. If the metric is higher than the high watermark, the scheme is deactivated. If the metric is between the mid watermark and the low watermark, the scheme is activated. If the metric is lower than the low watermark, the scheme is deactivated again. This is to allow users fall back to traditional page-granularity mechanisms. Link: https://lkml.kernel.org/r/20211019150731.16699-12-sj@kernel.org Signed-off-by: SeongJae Park Cc: Amit Shah Cc: Benjamin Herrenschmidt Cc: David Hildenbrand Cc: David Rientjes Cc: David Woodhouse Cc: Greg Thelen Cc: Jonathan Cameron Cc: Jonathan Corbet Cc: Leonard Foerster Cc: Marco Elver Cc: Markus Boehme Cc: Shakeel Butt Cc: Shuah Khan Signed-off-by: Andrew Morton --- include/linux/damon.h | 52 +++++++++++++++++++++ mm/damon/core.c | 97 +++++++++++++++++++++++++++++++++++++++- mm/damon/dbgfs.c | 5 +- 3 files changed, 151 insertions(+), 3 deletions(-) --- a/include/linux/damon.h~mm-damon-schemes-activate-schemes-based-on-a-watermarks-mechanism +++ a/include/linux/damon.h @@ -147,6 +147,45 @@ struct damos_quota { }; /** + * enum damos_wmark_metric - Represents the watermark metric. + * + * @DAMOS_WMARK_NONE: Ignore the watermarks of the given scheme. + * @DAMOS_WMARK_FREE_MEM_RATE: Free memory rate of the system in [0,1000]. + */ +enum damos_wmark_metric { + DAMOS_WMARK_NONE, + DAMOS_WMARK_FREE_MEM_RATE, +}; + +/** + * struct damos_watermarks - Controls when a given scheme should be activated. + * @metric: Metric for the watermarks. + * @interval: Watermarks check time interval in microseconds. + * @high: High watermark. + * @mid: Middle watermark. + * @low: Low watermark. + * + * If &metric is &DAMOS_WMARK_NONE, the scheme is always active. Being active + * means DAMON does monitoring and applying the action of the scheme to + * appropriate memory regions. Else, DAMON checks &metric of the system for at + * least every &interval microseconds and works as below. + * + * If &metric is higher than &high, the scheme is inactivated. If &metric is + * between &mid and &low, the scheme is activated. If &metric is lower than + * &low, the scheme is inactivated. + */ +struct damos_watermarks { + enum damos_wmark_metric metric; + unsigned long interval; + unsigned long high; + unsigned long mid; + unsigned long low; + +/* private: */ + bool activated; +}; + +/** * struct damos - Represents a Data Access Monitoring-based Operation Scheme. * @min_sz_region: Minimum size of target regions. * @max_sz_region: Maximum size of target regions. @@ -156,6 +195,7 @@ struct damos_quota { * @max_age_region: Maximum age of target regions. * @action: &damo_action to be applied to the target regions. * @quota: Control the aggressiveness of this scheme. + * @wmarks: Watermarks for automated (in)activation of this scheme. * @stat_count: Total number of regions that this scheme is applied. * @stat_sz: Total size of regions that this scheme is applied. * @list: List head for siblings. @@ -166,6 +206,14 @@ struct damos_quota { * those. To avoid consuming too much CPU time or IO resources for the * &action, "a is used. * + * To do the work only when needed, schemes can be activated for specific + * system situations using &wmarks. If all schemes that registered to the + * monitoring context are inactive, DAMON stops monitoring either, and just + * repeatedly checks the watermarks. + * + * If all schemes that registered to a &struct damon_ctx are inactive, DAMON + * stops monitoring and just repeatedly checks the watermarks. + * * After applying the &action to each region, &stat_count and &stat_sz is * updated to reflect the number of regions and total size of regions that the * &action is applied. @@ -179,6 +227,7 @@ struct damos { unsigned int max_age_region; enum damos_action action; struct damos_quota quota; + struct damos_watermarks wmarks; unsigned long stat_count; unsigned long stat_sz; struct list_head list; @@ -384,7 +433,8 @@ struct damos *damon_new_scheme( unsigned long min_sz_region, unsigned long max_sz_region, unsigned int min_nr_accesses, unsigned int max_nr_accesses, unsigned int min_age_region, unsigned int max_age_region, - enum damos_action action, struct damos_quota *quota); + enum damos_action action, struct damos_quota *quota, + struct damos_watermarks *wmarks); void damon_add_scheme(struct damon_ctx *ctx, struct damos *s); void damon_destroy_scheme(struct damos *s); --- a/mm/damon/core.c~mm-damon-schemes-activate-schemes-based-on-a-watermarks-mechanism +++ a/mm/damon/core.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -90,7 +91,8 @@ struct damos *damon_new_scheme( unsigned long min_sz_region, unsigned long max_sz_region, unsigned int min_nr_accesses, unsigned int max_nr_accesses, unsigned int min_age_region, unsigned int max_age_region, - enum damos_action action, struct damos_quota *quota) + enum damos_action action, struct damos_quota *quota, + struct damos_watermarks *wmarks) { struct damos *scheme; @@ -122,6 +124,13 @@ struct damos *damon_new_scheme( scheme->quota.charge_target_from = NULL; scheme->quota.charge_addr_from = 0; + scheme->wmarks.metric = wmarks->metric; + scheme->wmarks.interval = wmarks->interval; + scheme->wmarks.high = wmarks->high; + scheme->wmarks.mid = wmarks->mid; + scheme->wmarks.low = wmarks->low; + scheme->wmarks.activated = true; + return scheme; } @@ -582,6 +591,9 @@ static void damon_do_apply_schemes(struc unsigned long sz = r->ar.end - r->ar.start; struct timespec64 begin, end; + if (!s->wmarks.activated) + continue; + /* Check the quota */ if (quota->esz && quota->charged_sz >= quota->esz) continue; @@ -684,6 +696,9 @@ static void kdamond_apply_schemes(struct unsigned long cumulated_sz; unsigned int score, max_score = 0; + if (!s->wmarks.activated) + continue; + if (!quota->ms && !quota->sz) continue; @@ -924,6 +939,83 @@ static bool kdamond_need_stop(struct dam return true; } +static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric) +{ + struct sysinfo i; + + switch (metric) { + case DAMOS_WMARK_FREE_MEM_RATE: + si_meminfo(&i); + return i.freeram * 1000 / i.totalram; + default: + break; + } + return -EINVAL; +} + +/* + * Returns zero if the scheme is active. Else, returns time to wait for next + * watermark check in micro-seconds. + */ +static unsigned long damos_wmark_wait_us(struct damos *scheme) +{ + unsigned long metric; + + if (scheme->wmarks.metric == DAMOS_WMARK_NONE) + return 0; + + metric = damos_wmark_metric_value(scheme->wmarks.metric); + /* higher than high watermark or lower than low watermark */ + if (metric > scheme->wmarks.high || scheme->wmarks.low > metric) { + if (scheme->wmarks.activated) + pr_debug("inactivate a scheme (%d) for %s wmark\n", + scheme->action, + metric > scheme->wmarks.high ? + "high" : "low"); + scheme->wmarks.activated = false; + return scheme->wmarks.interval; + } + + /* inactive and higher than middle watermark */ + if ((scheme->wmarks.high >= metric && metric >= scheme->wmarks.mid) && + !scheme->wmarks.activated) + return scheme->wmarks.interval; + + if (!scheme->wmarks.activated) + pr_debug("activate a scheme (%d)\n", scheme->action); + scheme->wmarks.activated = true; + return 0; +} + +static void kdamond_usleep(unsigned long usecs) +{ + if (usecs > 100 * 1000) + schedule_timeout_interruptible(usecs_to_jiffies(usecs)); + else + usleep_range(usecs, usecs + 1); +} + +/* Returns negative error code if it's not activated but should return */ +static int kdamond_wait_activation(struct damon_ctx *ctx) +{ + struct damos *s; + unsigned long wait_time; + unsigned long min_wait_time = 0; + + while (!kdamond_need_stop(ctx)) { + damon_for_each_scheme(s, ctx) { + wait_time = damos_wmark_wait_us(s); + if (!min_wait_time || wait_time < min_wait_time) + min_wait_time = wait_time; + } + if (!min_wait_time) + return 0; + + kdamond_usleep(min_wait_time); + } + return -EBUSY; +} + static void set_kdamond_stop(struct damon_ctx *ctx) { mutex_lock(&ctx->kdamond_lock); @@ -952,6 +1044,9 @@ static int kdamond_fn(void *data) sz_limit = damon_region_sz_limit(ctx); while (!kdamond_need_stop(ctx)) { + if (kdamond_wait_activation(ctx)) + continue; + if (ctx->primitive.prepare_access_checks) ctx->primitive.prepare_access_checks(ctx); if (ctx->callback.after_sampling && --- a/mm/damon/dbgfs.c~mm-damon-schemes-activate-schemes-based-on-a-watermarks-mechanism +++ a/mm/damon/dbgfs.c @@ -195,6 +195,9 @@ static struct damos **str_to_schemes(con *nr_schemes = 0; while (pos < len && *nr_schemes < max_nr_schemes) { struct damos_quota quota = {}; + struct damos_watermarks wmarks = { + .metric = DAMOS_WMARK_NONE, + }; ret = sscanf(&str[pos], "%lu %lu %u %u %u %u %u %lu %lu %lu %u %u %u%n", @@ -212,7 +215,7 @@ static struct damos **str_to_schemes(con pos += parsed; scheme = damon_new_scheme(min_sz, max_sz, min_nr_a, max_nr_a, - min_age, max_age, action, "a); + min_age, max_age, action, "a, &wmarks); if (!scheme) goto fail;