From patchwork Tue Sep 1 18:52:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 11749395 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 F12A9166C for ; Tue, 1 Sep 2020 18:55:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D62832087D for ; Tue, 1 Sep 2020 18:55:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598986545; bh=WpAB5Q/wgQeiOnRPZUyObWMPUxFkDSosSG/MezRN9T4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZO6z1SFtVL1WLIR6Q1B/djaN0Qvh5VL8RD7lhAzTk3CmSn8UIbBmcs+uYyFir8fBl gdU1/O2KMCy0HH9hSaAwLoZVQkbbqGGH7vFiJ79d0HH7jI60qm8mhl1lSOf1DZrlVL 3jp8KbWevMBGINyYXYXxFhC7k4+aBOFMW19l9v+c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731834AbgIASyA (ORCPT ); Tue, 1 Sep 2020 14:54:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731761AbgIASxz (ORCPT ); Tue, 1 Sep 2020 14:53:55 -0400 Received: from mail-qk1-x744.google.com (mail-qk1-x744.google.com [IPv6:2607:f8b0:4864:20::744]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23BCDC061244; Tue, 1 Sep 2020 11:53:54 -0700 (PDT) Received: by mail-qk1-x744.google.com with SMTP id d20so1999253qka.5; Tue, 01 Sep 2020 11:53:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=W9a83GnSUegRN3aq2WoXDxZCM3FbBGqeK5GH+ZHyQQM=; b=Sn5CXW/oEMdzc5Gt1HU6u77M+wBIEpc5T8Nn2jWGaqsyzKTDbW9A0gR4v0fQ9A2SLF SiKpYQI0fJ/3cFymDBLZZKY8wtkhlTzY5FC/tGXq+mMSO6sAvHHyUP2Cpe0WCRRh5S51 MYoKmye0Kq8w0tJCoUkaopTaNumWCduYyOeTAlBlbNFqyxUyi12A5lWAQr0LRuNJhYY/ MRuPn6o+8MDCUmNK2gWYQkIxH3ASgcbDK8bs1dWX9xIyy6xWgl0fIHtm+ntd762jE5HC R4fSLhdyaH/5/YeKFXOcsc7uWdHy38d4f1QFu4lpjBQXLUJ0Vc99/k/bTCO4Zo+TvC7v gKVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=W9a83GnSUegRN3aq2WoXDxZCM3FbBGqeK5GH+ZHyQQM=; b=YZNvoE6yXZT33ntRVuNJe6isMSbrYvAWuVCJkX6OVF+pq9ySG7pd15u9f0t2eAozQ8 RH6LeVHZvk0IKLb0JS1aGK2GQ0jNBu18YMHzgTB919YKPZ/KKTt8s4SYwrPbWNIop4L8 CPnMnxbWzqJcJObSaOhuW9yaYu2+hDnogmKxF5ee33meLS5lNBhFnwNmhk+luebN1msP 6JhSvc1hxb+enaU3kv904Rc+5eZJtXykkrl1WehI1gujLoMKkMvLJywtdKDEsvIoaGEO aXnnbzakQiWzmeH3EVoJhbvN5PhKf52mEvbzHt5H8FiFid3xp8P+PCRicp+5MRG3ucQu udow== X-Gm-Message-State: AOAM533or11nAuLKnn1zQp+OeP/kw76jt6rOgeIKuXJwip+gYW4X/W5K vPyTQ8I7KoQNZZ+ZVNItB7o= X-Google-Smtp-Source: ABdhPJz2+2WxUDYy56VgqwLHTsVTQxppZsujilAbTKebn7Jwf2RduFUvodDK1dtgDwmEfpLn0usYeQ== X-Received: by 2002:a37:e509:: with SMTP id e9mr3124998qkg.469.1598986433172; Tue, 01 Sep 2020 11:53:53 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:a198]) by smtp.gmail.com with ESMTPSA id g4sm2339857qth.30.2020.09.01.11.53.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2020 11:53:52 -0700 (PDT) From: Tejun Heo To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, newella@fb.com, Tejun Heo Subject: [PATCH 16/27] blk-iocost: decouple vrate adjustment from surplus transfers Date: Tue, 1 Sep 2020 14:52:46 -0400 Message-Id: <20200901185257.645114-17-tj@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200901185257.645114-1-tj@kernel.org> References: <20200901185257.645114-1-tj@kernel.org> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Budget donations are inaccurate and could take multiple periods to converge. To prevent triggering vrate adjustments while surplus transfers were catching up, vrate adjustment was suppressed if donations were increasing, which was indicated by non-zero nr_surpluses. This entangling won't be necessary with the scheduled rewrite of donation mechanism which will make it precise and immediate. Let's decouple the two in preparation. Signed-off-by: Tejun Heo --- block/blk-iocost.c | 19 +++++++------------ include/trace/events/iocost.h | 13 ++++--------- 2 files changed, 11 insertions(+), 21 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index c1cd66cfa2a8..a3889a8b0a33 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -1508,7 +1508,7 @@ static void ioc_timer_fn(struct timer_list *timer) struct ioc_gq *iocg, *tiocg; struct ioc_now now; LIST_HEAD(surpluses); - int nr_surpluses = 0, nr_shortages = 0, nr_lagging = 0; + int nr_shortages = 0, nr_lagging = 0; u32 ppm_rthr = MILLION - ioc->params.qos[QOS_RPPM]; u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM]; u32 missed_ppm[2], rq_wait_pct; @@ -1640,10 +1640,8 @@ static void ioc_timer_fn(struct timer_list *timer) atomic64_add(delta, &iocg->vtime); atomic64_add(delta, &iocg->done_vtime); /* if usage is sufficiently low, maybe it can donate */ - if (surplus_adjusted_hweight_inuse(usage, hw_inuse)) { + if (surplus_adjusted_hweight_inuse(usage, hw_inuse)) list_add(&iocg->surplus_list, &surpluses); - nr_surpluses++; - } } else if (hw_inuse < hw_active) { u32 new_hwi, new_inuse; @@ -1673,7 +1671,7 @@ static void ioc_timer_fn(struct timer_list *timer) } } - if (!nr_shortages || !nr_surpluses) + if (!nr_shortages || list_empty(&surpluses)) goto skip_surplus_transfers; /* there are both shortages and surpluses, transfer surpluses */ @@ -1738,11 +1736,9 @@ static void ioc_timer_fn(struct timer_list *timer) /* * If there are IOs spanning multiple periods, wait - * them out before pushing the device harder. If - * there are surpluses, let redistribution work it - * out first. + * them out before pushing the device harder. */ - if (!nr_lagging && !nr_surpluses) + if (!nr_lagging) ioc->busy_level--; } else { /* @@ -1796,15 +1792,14 @@ static void ioc_timer_fn(struct timer_list *timer) } trace_iocost_ioc_vrate_adj(ioc, vrate, missed_ppm, rq_wait_pct, - nr_lagging, nr_shortages, - nr_surpluses); + nr_lagging, nr_shortages); atomic64_set(&ioc->vtime_rate, vrate); ioc_refresh_margins(ioc); } else if (ioc->busy_level != prev_busy_level || nr_lagging) { trace_iocost_ioc_vrate_adj(ioc, atomic64_read(&ioc->vtime_rate), missed_ppm, rq_wait_pct, nr_lagging, - nr_shortages, nr_surpluses); + nr_shortages); } ioc_refresh_params(ioc, false); diff --git a/include/trace/events/iocost.h b/include/trace/events/iocost.h index a905ecc0342f..ee024fe8fef6 100644 --- a/include/trace/events/iocost.h +++ b/include/trace/events/iocost.h @@ -128,11 +128,9 @@ DEFINE_EVENT(iocg_inuse_update, iocost_inuse_reset, TRACE_EVENT(iocost_ioc_vrate_adj, TP_PROTO(struct ioc *ioc, u64 new_vrate, u32 *missed_ppm, - u32 rq_wait_pct, int nr_lagging, int nr_shortages, - int nr_surpluses), + u32 rq_wait_pct, int nr_lagging, int nr_shortages), - TP_ARGS(ioc, new_vrate, missed_ppm, rq_wait_pct, nr_lagging, nr_shortages, - nr_surpluses), + TP_ARGS(ioc, new_vrate, missed_ppm, rq_wait_pct, nr_lagging, nr_shortages), TP_STRUCT__entry ( __string(devname, ioc_name(ioc)) @@ -144,7 +142,6 @@ TRACE_EVENT(iocost_ioc_vrate_adj, __field(u32, rq_wait_pct) __field(int, nr_lagging) __field(int, nr_shortages) - __field(int, nr_surpluses) ), TP_fast_assign( @@ -157,15 +154,13 @@ TRACE_EVENT(iocost_ioc_vrate_adj, __entry->rq_wait_pct = rq_wait_pct; __entry->nr_lagging = nr_lagging; __entry->nr_shortages = nr_shortages; - __entry->nr_surpluses = nr_surpluses; ), - TP_printk("[%s] vrate=%llu->%llu busy=%d missed_ppm=%u:%u rq_wait_pct=%u lagging=%d shortages=%d surpluses=%d", + TP_printk("[%s] vrate=%llu->%llu busy=%d missed_ppm=%u:%u rq_wait_pct=%u lagging=%d shortages=%d", __get_str(devname), __entry->old_vrate, __entry->new_vrate, __entry->busy_level, __entry->read_missed_ppm, __entry->write_missed_ppm, - __entry->rq_wait_pct, __entry->nr_lagging, __entry->nr_shortages, - __entry->nr_surpluses + __entry->rq_wait_pct, __entry->nr_lagging, __entry->nr_shortages ) );