From nobody Mon Jun 22 14:24:45 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45118C433F5 for ; Tue, 22 Mar 2022 11:06:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233907AbiCVLIQ (ORCPT ); Tue, 22 Mar 2022 07:08:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233906AbiCVLHz (ORCPT ); Tue, 22 Mar 2022 07:07:55 -0400 Received: from mail-qv1-xf2f.google.com (mail-qv1-xf2f.google.com [IPv6:2607:f8b0:4864:20::f2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E7A86B098 for ; Tue, 22 Mar 2022 04:06:28 -0700 (PDT) Received: by mail-qv1-xf2f.google.com with SMTP id r1so13384337qvr.12 for ; Tue, 22 Mar 2022 04:06:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xuSL+QxMbS0U0QUndRwl6D2gxTmGSO+ZRxuEuZ/Ya3o=; b=dk43yL4/ZQ0sR2tqOcbXgprBWl5VD3ZIPW5KMvzxKWYp/9NxAHWNTh/jc2G05OpZ5F 8dU/PY3xTCIH0vgGpDKw0/pHCJKsigNU2gTwBn4u+t8URbifSzMzzVZoLFPG96t4jTL1 fOhJg5fR2/mdZQXpUbOTWSMTnbmaA3WRlaFGqkTzmS46JA+cao4t66cIRphNiTrRxs2+ rEKZWVXIYSaExXeK14L8uPz8WSbtReYWvhooy/p64o/9w+LYOt4zPy2zK6w3xadXMsJy xzdoEyI4U6Bz5f2Vhs+GqMrPqOWYEoy9N7w8hS9cMkVRdzd7sjIGrXgwfU6YP6u3IHjG XG+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xuSL+QxMbS0U0QUndRwl6D2gxTmGSO+ZRxuEuZ/Ya3o=; b=WHp/fVfseqMR3xvBtwfnGvnmeX1fnBZGc0ebRfCByj4pS8EAGRiOCDiNIK9KzVObiv PK1t/6gmhBjgIFLKBFXFZSCsrM4pgKauHqbv3i3KfQ4bsR4wL+wL8G7WZ6UUXVjWkHrm c+rmG6VjDsI9lhZG8zPCdWMhN3KAxHgWdQrTHzhUNewQqeChlBJTWiEO19EDfBEKs/s4 B0VHqqRE9cmnID1nY+ZLz1Vl87RYmx6HUPa1/qqqNDuaGIhJWiC21LmhUxxMhpKsbTHd Yx/LCAp/PlQRh2/3zBF9AEXqc3XM4053ps3UiMhiuXGTaPeXcubBdYmjsGpTz2EKNl7l HdKA== X-Gm-Message-State: AOAM530sDLHT52bt00uWp5W8dcHq2FpGlhM+8WzXxPOD9zB5SHm9kdOs j6+65fvyD866CuB4QbbwP80= X-Google-Smtp-Source: ABdhPJzEipQGfEX0E/yScKf40M4KhluyIvmkv7Y4h6TidcHPBlm8r0YXn4rVVut1u3n94y5GhnbmAA== X-Received: by 2002:a0c:f70d:0:b0:441:4558:b70c with SMTP id w13-20020a0cf70d000000b004414558b70cmr1657348qvn.82.1647947187250; Tue, 22 Mar 2022 04:06:27 -0700 (PDT) Received: from localhost.localdomain ([193.203.214.57]) by smtp.gmail.com with ESMTPSA id p13-20020a05622a048d00b002e1ce0c627csm14284668qtx.58.2022.03.22.04.06.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Mar 2022 04:06:26 -0700 (PDT) From: cgel.zte@gmail.com X-Google-Original-From: yang.yang29@zte.com.cn To: akpm@linux-foundation.org, david@redhat.com Cc: bsingharora@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Yang Yang , Ran Xiaokai Subject: [PATCH] delayacct: track delays from COW Date: Tue, 22 Mar 2022 11:04:45 +0000 Message-Id: <20220322110444.2340748-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yang Yang Delay accounting does not track the delay of COW. When tasks trigger much COW, it may spend a amount of time waiting for it. To get the impact of tasks in COW, measure the delay when it happens. This could help users to do tunnings, such as decide whether to use ksm or not. Also update tools/accounting/getdelays.c: / # ./getdelays -dl -p 231 print delayacct stats ON listen forever PID 231 CPU count real total virtual total delay total del= ay average 6247 1859000000 2154070021 1674255063 = 0.268ms IO count delay total delay average 0 0 0ms SWAP count delay total delay average 0 0 0ms RECLAIM count delay total delay average 0 0 0ms THRASHING count delay total delay average 0 0 0ms COMPACT count delay total delay average 3 72758 0ms COW count delay total delay average 3635 271567604 0ms Signed-off-by: Yang Yang Reviewed-by: Ran Xiaokai --- include/linux/delayacct.h | 28 ++++++++++++++++++++++++++++ include/uapi/linux/taskstats.h | 6 +++++- kernel/delayacct.c | 16 ++++++++++++++++ mm/memory.c | 8 ++++++++ tools/accounting/getdelays.c | 8 +++++++- 5 files changed, 64 insertions(+), 2 deletions(-) diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h index 6b16a6930a19..89b202c695d3 100644 --- a/include/linux/delayacct.h +++ b/include/linux/delayacct.h @@ -45,9 +45,13 @@ struct task_delay_info { u64 compact_start; u64 compact_delay; /* wait for memory compact */ =20 + u64 cow_start; + u64 cow_delay; /* wait for cow */ + u32 freepages_count; /* total count of memory reclaim */ u32 thrashing_count; /* total count of thrash waits */ u32 compact_count; /* total count of memory compact */ + u32 cow_count; /* total count of cow */ }; #endif =20 @@ -75,6 +79,8 @@ extern void __delayacct_swapin_start(void); extern void __delayacct_swapin_end(void); extern void __delayacct_compact_start(void); extern void __delayacct_compact_end(void); +extern void __delayacct_cow_start(void); +extern void __delayacct_cow_end(void); =20 static inline void delayacct_tsk_init(struct task_struct *tsk) { @@ -191,6 +197,24 @@ static inline void delayacct_compact_end(void) __delayacct_compact_end(); } =20 +static inline void delayacct_cow_start(void) +{ + if (!static_branch_unlikely(&delayacct_key)) + return; + + if (current->delays) + __delayacct_cow_start(); +} + +static inline void delayacct_cow_end(void) +{ + if (!static_branch_unlikely(&delayacct_key)) + return; + + if (current->delays) + __delayacct_cow_end(); +} + #else static inline void delayacct_init(void) {} @@ -225,6 +249,10 @@ static inline void delayacct_compact_start(void) {} static inline void delayacct_compact_end(void) {} +static inline void delayacct_cow_start(void) +{} +static inline void delayacct_cow_end(void) +{} =20 #endif /* CONFIG_TASK_DELAY_ACCT */ =20 diff --git a/include/uapi/linux/taskstats.h b/include/uapi/linux/taskstats.h index 12327d32378f..cfb9a2e0e95a 100644 --- a/include/uapi/linux/taskstats.h +++ b/include/uapi/linux/taskstats.h @@ -34,7 +34,7 @@ */ =20 =20 -#define TASKSTATS_VERSION 11 +#define TASKSTATS_VERSION 12 #define TS_COMM_LEN 32 /* should be >=3D TASK_COMM_LEN * in linux/sched.h */ =20 @@ -176,6 +176,10 @@ struct taskstats { /* Delay waiting for memory compact */ __u64 compact_count; __u64 compact_delay_total; + + /* Delay waiting for cow */ + __u64 cow_count; + __u64 cow_delay_total; }; =20 =20 diff --git a/kernel/delayacct.c b/kernel/delayacct.c index 2c1e18f7c5cf..c9a833270fe0 100644 --- a/kernel/delayacct.c +++ b/kernel/delayacct.c @@ -177,11 +177,14 @@ int delayacct_add_tsk(struct taskstats *d, struct tas= k_struct *tsk) d->thrashing_delay_total =3D (tmp < d->thrashing_delay_total) ? 0 : tmp; tmp =3D d->compact_delay_total + tsk->delays->compact_delay; d->compact_delay_total =3D (tmp < d->compact_delay_total) ? 0 : tmp; + tmp =3D d->cow_delay_total + tsk->delays->cow_delay; + d->cow_delay_total =3D (tmp < d->cow_delay_total) ? 0 : tmp; d->blkio_count +=3D tsk->delays->blkio_count; d->swapin_count +=3D tsk->delays->swapin_count; d->freepages_count +=3D tsk->delays->freepages_count; d->thrashing_count +=3D tsk->delays->thrashing_count; d->compact_count +=3D tsk->delays->compact_count; + d->cow_count +=3D tsk->delays->cow_count; raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); =20 return 0; @@ -249,3 +252,16 @@ void __delayacct_compact_end(void) ¤t->delays->compact_delay, ¤t->delays->compact_count); } + +void __delayacct_cow_start(void) +{ + current->delays->cow_start =3D local_clock(); +} + +void __delayacct_cow_end(void) +{ + delayacct_end(¤t->delays->lock, + ¤t->delays->cow_start, + ¤t->delays->cow_delay, + ¤t->delays->cow_count); +} diff --git a/mm/memory.c b/mm/memory.c index 4499cf09c21f..4111f97c91a0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3006,6 +3006,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) int page_copied =3D 0; struct mmu_notifier_range range; =20 + delayacct_cow_start(); + if (unlikely(anon_vma_prepare(vma))) goto oom; =20 @@ -3030,6 +3032,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) put_page(new_page); if (old_page) put_page(old_page); + + delayacct_cow_end(); return 0; } } @@ -3128,12 +3132,16 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) free_swap_cache(old_page); put_page(old_page); } + + delayacct_cow_end(); return page_copied ? VM_FAULT_WRITE : 0; oom_free_new: put_page(new_page); oom: if (old_page) put_page(old_page); + + delayacct_cow_end(); return VM_FAULT_OOM; } =20 diff --git a/tools/accounting/getdelays.c b/tools/accounting/getdelays.c index 11e86739456d..0f6e4831a77b 100644 --- a/tools/accounting/getdelays.c +++ b/tools/accounting/getdelays.c @@ -207,6 +207,8 @@ static void print_delayacct(struct taskstats *t) "THRASHING%12s%15s%15s\n" " %15llu%15llu%15llums\n" "COMPACT %12s%15s%15s\n" + " %15llu%15llu%15llums\n" + "COW %15s%15s%15s\n" " %15llu%15llu%15llums\n", "count", "real total", "virtual total", "delay total", "delay average", @@ -234,7 +236,11 @@ static void print_delayacct(struct taskstats *t) "count", "delay total", "delay average", (unsigned long long)t->compact_count, (unsigned long long)t->compact_delay_total, - average_ms(t->compact_delay_total, t->compact_count)); + average_ms(t->compact_delay_total, t->compact_count), + "count", "delay total", "delay average", + (unsigned long long)t->cow_count, + (unsigned long long)t->cow_delay_total, + average_ms(t->cow_delay_total, t->cow_count)); } =20 static void task_context_switch_counts(struct taskstats *t) --=20 2.25.1