From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 305E3C433F5 for ; Tue, 19 Oct 2021 15:07:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A8D76138D for ; Tue, 19 Oct 2021 15:07:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233392AbhJSPKK (ORCPT ); Tue, 19 Oct 2021 11:10:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:57828 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232813AbhJSPKJ (ORCPT ); Tue, 19 Oct 2021 11:10:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 66CB96115A; Tue, 19 Oct 2021 15:07:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634656076; bh=ByvqifPgFEto66JEiyYk2/53Jz/4J13sSehCABtE1uw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UhCDr6dvWjujod3djUv2+1FJoj9agErgOnoiP5UL150vNbA4mzARrg1vaZQp9h3CQ WUHGzMuDmOGfvbhLLdKEiQfjDXLjHgnHKSva6iKHIAqdoBxPVY3Y9ZRFxTHhVTAc9J cevNP99ZD1RIZ0lEB69xjN794YEZo8pLfR7bmndCF9lnHKMQtIQ1u8K5Ol5Ao5BFmT 9e9dv82BUt6dB1SXqL2dkgM5NLL7J4RnvhIc3HB03utxCLccKWXY+1TyuLw6r0brOD dlBaZ+7i0vdmgTgp9tbT12ck1v9LIoaz3JAkSeCz2YN/hjKnfsvkU2X/E9jcjUEG1Q 7HH2VU9Cae9pQ== From: SeongJae Park To: akpm@linux-foundation.org Cc: SeongJae Park , Jonathan.Cameron@Huawei.com, 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, markubo@amazon.de, rientjes@google.com, shakeelb@google.com, shuah@kernel.org, linux-damon@amazon.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 04/15] mm/damon/schemes: Implement time quota Date: Tue, 19 Oct 2021 15:07:20 +0000 Message-Id: <20211019150731.16699-5-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211019150731.16699-1-sj@kernel.org> References: <20211019150731.16699-1-sj@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org The size quota feature of DAMOS is useful for IO resource-critical systems, but not so intuitive for CPU time-critical systems. Systems using zram or zswap-like swap device would be examples. To provide another intuitive ways for such systems, this commit implements time-based quota for DAMON-based Operation Schemes. If the quota is set, DAMOS tries to use only up to the user-defined quota of CPU time within a given time window. Signed-off-by: SeongJae Park --- include/linux/damon.h | 25 +++++++++++++++++++----- mm/damon/core.c | 45 ++++++++++++++++++++++++++++++++++++++----- 2 files changed, 60 insertions(+), 10 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index 1fec32e18319..5347f940818e 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -91,20 +91,35 @@ enum damos_action { /** * struct damos_quota - Controls the aggressiveness of the given scheme. + * @ms: Maximum milliseconds that the scheme can use. * @sz: Maximum bytes of memory that the action can be applied. * @reset_interval: Charge reset interval in milliseconds. * * To avoid consuming too much CPU time or IO resources for applying the - * &struct damos->action to large memory, DAMON allows users to set a size - * quota. The quota can be set by writing non-zero values to &sz. If the size - * quota is set, DAMON tries to apply the action only up to &sz bytes within - * &reset_interval. + * &struct damos->action to large memory, DAMON allows users to set time and/or + * size quotas. The quotas can be set by writing non-zero values to &ms and + * &sz, respectively. If the time quota is set, DAMON tries to use only up to + * &ms milliseconds within &reset_interval for applying the action. If the + * size quota is set, DAMON tries to apply the action only up to &sz bytes + * within &reset_interval. + * + * Internally, the time quota is transformed to a size quota using estimated + * throughput of the scheme's action. DAMON then compares it against &sz and + * uses smaller one as the effective quota. */ struct damos_quota { + unsigned long ms; unsigned long sz; unsigned long reset_interval; -/* private: For charging the quota */ +/* private: */ + /* For throughput estimation */ + unsigned long total_charged_sz; + unsigned long total_charged_ns; + + unsigned long esz; /* Effective size quota in bytes */ + + /* For charging the quota */ unsigned long charged_sz; unsigned long charged_from; struct damon_target *charge_target_from; diff --git a/mm/damon/core.c b/mm/damon/core.c index 693b75bc3450..d1da4bef96ed 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -107,8 +107,12 @@ struct damos *damon_new_scheme( scheme->stat_sz = 0; INIT_LIST_HEAD(&scheme->list); + scheme->quota.ms = quota->ms; scheme->quota.sz = quota->sz; scheme->quota.reset_interval = quota->reset_interval; + scheme->quota.total_charged_sz = 0; + scheme->quota.total_charged_ns = 0; + scheme->quota.esz = 0; scheme->quota.charged_sz = 0; scheme->quota.charged_from = 0; scheme->quota.charge_target_from = NULL; @@ -550,9 +554,10 @@ static void damon_do_apply_schemes(struct damon_ctx *c, damon_for_each_scheme(s, c) { struct damos_quota *quota = &s->quota; unsigned long sz = r->ar.end - r->ar.start; + struct timespec64 begin, end; /* Check the quota */ - if (quota->sz && quota->charged_sz >= quota->sz) + if (quota->esz && quota->charged_sz >= quota->esz) continue; /* Skip previously charged regions */ @@ -597,16 +602,21 @@ static void damon_do_apply_schemes(struct damon_ctx *c, /* Apply the scheme */ if (c->primitive.apply_scheme) { - if (quota->sz && quota->charged_sz + sz > quota->sz) { - sz = ALIGN_DOWN(quota->sz - quota->charged_sz, + if (quota->esz && + quota->charged_sz + sz > quota->esz) { + sz = ALIGN_DOWN(quota->esz - quota->charged_sz, DAMON_MIN_REGION); if (!sz) goto update_stat; damon_split_region_at(c, t, r, sz); } + ktime_get_coarse_ts64(&begin); c->primitive.apply_scheme(c, t, r, s); + ktime_get_coarse_ts64(&end); + quota->total_charged_ns += timespec64_to_ns(&end) - + timespec64_to_ns(&begin); quota->charged_sz += sz; - if (quota->sz && quota->charged_sz >= quota->sz) { + if (quota->esz && quota->charged_sz >= quota->esz) { quota->charge_target_from = t; quota->charge_addr_from = r->ar.end + 1; } @@ -620,6 +630,29 @@ static void damon_do_apply_schemes(struct damon_ctx *c, } } +/* Shouldn't be called if quota->ms and quota->sz are zero */ +static void damos_set_effective_quota(struct damos_quota *quota) +{ + unsigned long throughput; + unsigned long esz; + + if (!quota->ms) { + quota->esz = quota->sz; + return; + } + + if (quota->total_charged_ns) + throughput = quota->total_charged_sz * 1000000 / + quota->total_charged_ns; + else + throughput = PAGE_SIZE * 1024; + esz = throughput * quota->ms; + + if (quota->sz && quota->sz < esz) + esz = quota->sz; + quota->esz = esz; +} + static void kdamond_apply_schemes(struct damon_ctx *c) { struct damon_target *t; @@ -629,15 +662,17 @@ static void kdamond_apply_schemes(struct damon_ctx *c) damon_for_each_scheme(s, c) { struct damos_quota *quota = &s->quota; - if (!quota->sz) + if (!quota->ms && !quota->sz) continue; /* New charge window starts */ if (time_after_eq(jiffies, quota->charged_from + msecs_to_jiffies( quota->reset_interval))) { + quota->total_charged_sz += quota->charged_sz; quota->charged_from = jiffies; quota->charged_sz = 0; + damos_set_effective_quota(quota); } } -- 2.17.1