From patchwork Thu Aug 1 12:21:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Leizhen \(ThunderTown\)" X-Patchwork-Id: 170376 Delivered-To: patch@linaro.org Received: by 2002:a92:512:0:0:0:0:0 with SMTP id q18csp5364742ile; Thu, 1 Aug 2019 05:22:31 -0700 (PDT) X-Google-Smtp-Source: APXvYqy7ePtJj/228Ss8UA1EhgJWDZOV0GX8kdQ5yWPcT77xPfVtJVu+fXfh6od/bqbwHiKblHjv X-Received: by 2002:a17:90a:17a6:: with SMTP id q35mr8483584pja.118.1564662151552; Thu, 01 Aug 2019 05:22:31 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1564662151; cv=none; d=google.com; s=arc-20160816; b=m2s3guXsN5DwXrIw5S847V0Je42reMBMP0ljgojHI85bQf7f6bNUR9Y9T5U2mGiagk ZoC/MiAxsuaSbrhco9pQHNnNaYVce9lBEoF2vjJxnyZqB3ICO9BmBF8vdF9Q3uaE1lu6 3DCWtKaB1kGBO/1L42FyDiQFF+Iy4qzzvdsb2st3qoivoPseXXOT98lblHoxJugyeSaB arWTaduAkX0X9aF/N4IMjKXzauzAloCothN/ZrS6RBnmkT4u1uoH2/cNWef0/1rP1wpk j70Z3E37/fefHV/GYv9zQlJWjRP5mC0+7n4dE1ORcqkdB4snvj6uKRva0AUFnW5V+yhW 6TMQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=y1TLLNS0QZOer/hWVZKuRzBigK1roVklGOm1nyXB1L4=; b=ZcorCMRukeckamcvhm63HJz3WT6F3gIC/yg6CE9ULnV4TkxypshPiPmWvPU9+77od6 my05Dv6+6LDLRGbmEi31mHUjNPnR87Tv5GSFoYavq5wwVLI/8DQdOKwjfv25cU6UtDUJ Pta3U3pI8BPxT4jpLNu/VV3l7ZKzur6dhPFVi9fvXn92Q8z5ogf1dnlphAvDtvvHGS39 b7ch2t5sGd3D0vZQiN654a7A4JtdRUnzjZPZLaZLqxzNajEOg+dNxCuaxGKWjvJJq2DN gZuPP4BOwrpmKXZ7mPGUK5O8h/YgJ0juaeursyYAeDqCVDVI0GI22ZWpjF3hwmEMiUco IW6A== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id i189si38269331pge.253.2019.08.01.05.22.31; Thu, 01 Aug 2019 05:22:31 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731197AbfHAMW3 (ORCPT + 29 others); Thu, 1 Aug 2019 08:22:29 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:3691 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728791AbfHAMW3 (ORCPT ); Thu, 1 Aug 2019 08:22:29 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id EDF1CC8C7A220F45FF58; Thu, 1 Aug 2019 20:22:26 +0800 (CST) Received: from HGHY4L002753561.china.huawei.com (10.133.215.186) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.439.0; Thu, 1 Aug 2019 20:22:17 +0800 From: Zhen Lei To: Jean-Philippe Brucker , John Garry , Robin Murphy , Will Deacon , Joerg Roedel , linux-arm-kernel , iommu , linux-kernel CC: Zhen Lei Subject: [PATCH 2/2] iommu/iova: enhance the rcache optimization Date: Thu, 1 Aug 2019 20:21:54 +0800 Message-ID: <20190801122154.18820-2-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.21.0.windows.1 In-Reply-To: <20190801122154.18820-1-thunder.leizhen@huawei.com> References: <20190801122154.18820-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.133.215.186] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The rcache method caches the freed IOVAs, to improve the performance of IOVAs allocation and release. This is usually okay, but it maybe declined in some special scenarios. For example, currently the IOVA_RANGE_CACHE_MAX_SIZE is 6, and for ecch size, contains: MAX_GLOBAL_MAGS=32 shareable depot magazines, each vcpu has two magazines(cpu_rcaches->loaded and cpu_rcaches->prev). In an extreme case, it can max cache ((num_possible_cpus() * 2 + 32) * 128 * 6) IOVAs, it's very large. The worst case happens when the depot magazines of a certain size(usually 4K) is full, further free_iova_fast() invoking will cause iova_magazine_free_pfns() to be called. As the above saied, too many IOVAs buffered, so that the RB tree is very large, the iova_magazine_free_pfns()-->private_find_iova(), and the missed iova allocation: alloc_iova()-->__alloc_and_insert_iova_range() will spend too much time. And that the current rcache method have no cleanup operation, the buffered IOVAs will only increase but not decrease. For my FIO stress test scenario, the performance drop about 35%, and can not recover even if re-execute the test cases. Jobs: 21 (f=21): [2.3% done] [8887M/0K /s] [2170K/0 iops] Jobs: 21 (f=21): [2.3% done] [8902M/0K /s] [2173K/0 iops] Jobs: 21 (f=21): [2.3% done] [6010M/0K /s] [1467K/0 iops] Jobs: 21 (f=21): [2.3% done] [5397M/0K /s] [1318K/0 iops] So that, I add the statistic about the rcache, when the above case happened, release the IOVAs which are not hit. Jobs: 21 (f=21): [100.0% done] [10324M/0K /s] [2520K/0 iops] Jobs: 21 (f=21): [100.0% done] [10290M/0K /s] [2512K/0 iops] Jobs: 21 (f=21): [100.0% done] [10035M/0K /s] [2450K/0 iops] Jobs: 21 (f=21): [100.0% done] [10214M/0K /s] [2494K/0 iops] Signed-off-by: Zhen Lei --- drivers/iommu/iova.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++- include/linux/iova.h | 1 + 2 files changed, 83 insertions(+), 1 deletion(-) -- 1.8.3 diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 4b7a9efa0ef40af..f3828f4add25375 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -23,6 +23,8 @@ static unsigned long iova_rcache_get(struct iova_domain *iovad, unsigned long limit_pfn); static void init_iova_rcaches(struct iova_domain *iovad); static void free_iova_rcaches(struct iova_domain *iovad); +static void iova_compact_rcache(struct iova_domain *iovad, + struct iova_rcache *curr_rcache); static void fq_destroy_all_entries(struct iova_domain *iovad); static void fq_flush_timeout(struct timer_list *t); @@ -781,6 +783,8 @@ struct iova_magazine { struct iova_cpu_rcache { spinlock_t lock; + bool prev_mag_hit; + unsigned long nr_hit; struct iova_magazine *loaded; struct iova_magazine *prev; }; @@ -934,6 +938,7 @@ static bool __iova_rcache_insert(struct iova_domain *iovad, if (mag_to_free) { iova_magazine_free_pfns(mag_to_free, iovad); iova_magazine_free(mag_to_free); + iova_compact_rcache(iovad, rcache); } return can_insert; @@ -971,18 +976,22 @@ static unsigned long __iova_rcache_get(struct iova_rcache *rcache, } else if (!iova_magazine_empty(cpu_rcache->prev)) { swap(cpu_rcache->prev, cpu_rcache->loaded); has_pfn = true; + cpu_rcache->prev_mag_hit = true; } else { spin_lock(&rcache->lock); if (rcache->depot_size > 0) { iova_magazine_free(cpu_rcache->loaded); cpu_rcache->loaded = rcache->depot[--rcache->depot_size]; has_pfn = true; + rcache->depot_mags_hit = true; } spin_unlock(&rcache->lock); } - if (has_pfn) + if (has_pfn) { + cpu_rcache->nr_hit++; iova_pfn = iova_magazine_pop(cpu_rcache->loaded, limit_pfn); + } spin_unlock_irqrestore(&cpu_rcache->lock, flags); @@ -1049,5 +1058,77 @@ void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad) } } +static void iova_compact_percpu_mags(struct iova_domain *iovad, + struct iova_rcache *rcache) +{ + unsigned int cpu; + + for_each_possible_cpu(cpu) { + unsigned long flags; + struct iova_cpu_rcache *cpu_rcache; + + cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu); + + spin_lock_irqsave(&cpu_rcache->lock, flags); + if (!cpu_rcache->prev_mag_hit) + iova_magazine_free_pfns(cpu_rcache->prev, iovad); + + if (cpu_rcache->nr_hit < IOVA_MAG_SIZE) + iova_magazine_compact_pfns(cpu_rcache->loaded, + iovad, + cpu_rcache->nr_hit); + + cpu_rcache->nr_hit = 0; + cpu_rcache->prev_mag_hit = false; + spin_unlock_irqrestore(&cpu_rcache->lock, flags); + } +} + +static void iova_compact_depot_mags(struct iova_domain *iovad, + struct iova_rcache *rcache) +{ + int i; + unsigned long depot_size; + struct iova_magazine *depot[MAX_GLOBAL_MAGS]; + + spin_lock(&rcache->lock); + if (!rcache->depot_size || rcache->depot_mags_hit) { + spin_unlock(&rcache->lock); + return; + } + + depot_size = rcache->depot_size; + for (i = 0; i < depot_size; i++) + depot[i] = rcache->depot[i]; + rcache->depot_size = 0; + rcache->depot_mags_hit = false; + spin_unlock(&rcache->lock); + + for (i = 0; i < depot_size; i++) { + iova_magazine_free_pfns(depot[i], iovad); + iova_magazine_free(depot[i]); + } +} + +static void iova_compact_rcache(struct iova_domain *iovad, + struct iova_rcache *curr_rcache) +{ + int i; + struct iova_rcache *rcache; + + for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; i++) { + rcache = &iovad->rcaches[i]; + + /* + * Don's compact current rcache, that maybe reused immediately + */ + if (rcache == curr_rcache) + continue; + + iova_compact_percpu_mags(iovad, rcache); + iova_compact_depot_mags(iovad, rcache); + } +} + MODULE_AUTHOR("Anil S Keshavamurthy "); MODULE_LICENSE("GPL"); diff --git a/include/linux/iova.h b/include/linux/iova.h index a0637abffee88b0..44f35b2641b736c 100644 --- a/include/linux/iova.h +++ b/include/linux/iova.h @@ -30,6 +30,7 @@ struct iova { struct iova_rcache { spinlock_t lock; + bool depot_mags_hit; unsigned long depot_size; struct iova_magazine *depot[MAX_GLOBAL_MAGS]; struct iova_cpu_rcache __percpu *cpu_rcaches;