From patchwork Tue Jun 28 22:09:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 12899026 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 9E10FC433EF for ; Tue, 28 Jun 2022 22:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230398AbiF1WJs (ORCPT ); Tue, 28 Jun 2022 18:09:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230359AbiF1WJq (ORCPT ); Tue, 28 Jun 2022 18:09:46 -0400 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 844CB344FC for ; Tue, 28 Jun 2022 15:09:45 -0700 (PDT) Received: by mail-pf1-x449.google.com with SMTP id a71-20020a621a4a000000b005259104d9b2so3641869pfa.3 for ; Tue, 28 Jun 2022 15:09:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Ar/TwF8lq5bFbqZHf9pZvB65YclrhW3IS7sSA1BsQDg=; b=pfL22Ng6pzLvqLLBP98qcLfLr68c9UrDTPsuK4SmENqAoH54ekraevxSvAT3Zr2dW4 8PWtU6KCm2/b8+SVQwc/NjsVuC1N2XRKJPd60HT9TVPAZjlrs5v7NCcCf1SdeIAtOxvn Wq4mJs8oRc3S6U/OGFELy/aucVizKhgd2vVUXuoHHaej4XL+gd+0uHk751t5VnPdwPDr MTUza4pM4XE/qPXrA/kAlTNHBkzAuPyhewKLo9FVbRFy7fiyRMDtwoBknb53Dnsufu1l cB/nwVstbR5Ct9kLsuYh83++YNOAy/uslrdkr313avX3kPT7zmts40/8kHi/gWEGYCB4 dJ7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Ar/TwF8lq5bFbqZHf9pZvB65YclrhW3IS7sSA1BsQDg=; b=gT2N8jyCWKXrrcFPoRjE++DRTJhcfcsYi5sKuqFtb7DfMS60/mJma0FRudAH6I+zUC Y0dAIKYXhGvTtLa34fCIMKWndmK5iElx8+4DHrsyGdlGhGUh3+zZ9JPruJ6p/EBp5f0A NeigWX7w4sDZcPNPSnyVarRfUy72J4VL/vEtBIB9OCTMGlejkXeUjSg2zYzUryRYHO78 NOELtRoS28btBcJz496Y/rKDbuKoparuc5YvaOoDrEu0sIzbmJZu5vNgiqbVqFdt1gea WQ8GCxSz3jyrckF/XXOiGwdM0S5aISoq2OqCy2jOAs6zwl3Ba8pTpoDf84boyYfY5v6q qLow== X-Gm-Message-State: AJIora+2LaZQVPRpbsjDRcTaQ24W2mtvQoic32fM6PmnKjgVYuN1oH8C vp62IG4nBFcI3k02DZ6SQ9mKYnlftn0ZemR4 X-Google-Smtp-Source: AGRyM1vkRcRJ1tlgIcIQka52LZiOjuQOq+sfYK/G902mhBRAIiM7J/rour3nZbiO5D1W8ZLMVYOcRzoGp2iOTMLH X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a17:902:e808:b0:16a:75be:2ba with SMTP id u8-20020a170902e80800b0016a75be02bamr7025411plg.85.1656454184962; Tue, 28 Jun 2022 15:09:44 -0700 (PDT) Date: Tue, 28 Jun 2022 22:09:35 +0000 In-Reply-To: <20220628220938.3657876-1-yosryahmed@google.com> Message-Id: <20220628220938.3657876-2-yosryahmed@google.com> Mime-Version: 1.0 References: <20220628220938.3657876-1-yosryahmed@google.com> X-Mailer: git-send-email 2.37.0.rc0.161.g10f37bed90-goog Subject: [PATCH v6 1/4] mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses. From: Yosry Ahmed To: Tejun Heo , Johannes Weiner , Zefan Li , Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Andrew Morton , Michal Hocko , Roman Gushchin , Shakeel Butt , Oliver Upton Cc: Huang@google.com, Shaoqin , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-mm@kvack.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org We keep track of several kernel memory stats (total kernel memory, page tables, stack, vmalloc, etc) on multiple levels (global, per-node, per-memcg, etc). These stats give insights to users to how much memory is used by the kernel and for what purposes. Currently, memory used by kvm mmu is not accounted in any of those kernel memory stats. This patch series accounts the memory pages used by KVM for page tables in those stats in a new NR_SECONDARY_PAGETABLE stat. This stat can be later extended to account for other types of secondary pages tables (e.g. iommu page tables). KVM has a decent number of large allocations that aren't for page tables, but for most of them, the number/size of those allocations scales linearly with either the number of vCPUs or the amount of memory assigned to the VM. KVM's secondary page table allocations do not scale linearly, especially when nested virtualization is in use. From a KVM perspective, NR_SECONDARY_PAGETABLE will scale with KVM's per-VM pages_{4k,2m,1g} stats unless the guest is doing something bizarre (e.g. accessing only 4kb chunks of 2mb pages so that KVM is forced to allocate a large number of page tables even though the guest isn't accessing that much memory). However, someone would need to either understand how KVM works to make that connection, or know (or be told) to go look at KVM's stats if they're running VMs to better decipher the stats. Furthermore, having NR_PAGETABLE side-by-side with NR_SECONDARY_PAGETABLE is informative. For example, when backing a VM with THP vs. HugeTLB, NR_SECONDARY_PAGETABLE is roughly the same, but NR_PAGETABLE is an order of magnitude higher with THP. So having this stat will at the very least prove to be useful for understanding tradeoffs between VM backing types, and likely even steer folks towards potential optimizations. The original discussion with more details about the rationale: https://lore.kernel.org/all/87ilqoi77b.wl-maz@kernel.org This stat will be used by subsequent patches to count KVM mmu memory usage. Signed-off-by: Yosry Ahmed Acked-by: Shakeel Butt Acked-by: Marc Zyngier --- Documentation/admin-guide/cgroup-v2.rst | 5 +++++ Documentation/filesystems/proc.rst | 4 ++++ drivers/base/node.c | 2 ++ fs/proc/meminfo.c | 2 ++ include/linux/mmzone.h | 1 + mm/memcontrol.c | 1 + mm/page_alloc.c | 6 +++++- mm/vmstat.c | 1 + 8 files changed, 21 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 176298f2f4def..e06db032bdbf3 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1340,6 +1340,11 @@ PAGE_SIZE multiple when read back. pagetables Amount of memory allocated for page tables. + sec_pagetables + Amount of memory allocated for secondary page tables, + this currently includes KVM mmu allocations on x86 + and arm64. + percpu (npn) Amount of memory used for storing per-cpu kernel data structures. diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 1bc91fb8c321a..aa2a05b585772 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -977,6 +977,7 @@ Example output. You may not have all of these fields. SUnreclaim: 142336 kB KernelStack: 11168 kB PageTables: 20540 kB + SecPageTables: 0 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB @@ -1085,6 +1086,9 @@ KernelStack Memory consumed by the kernel stacks of all tasks PageTables Memory consumed by userspace page tables +SecPageTables + Memory consumed by secondary page tables, this currently + currently includes KVM mmu allocations on x86 and arm64. NFS_Unstable Always zero. Previous counted pages which had been written to the server, but has not been committed to stable storage. diff --git a/drivers/base/node.c b/drivers/base/node.c index 0ac6376ef7a10..5ad56a0cd5937 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -433,6 +433,7 @@ static ssize_t node_read_meminfo(struct device *dev, "Node %d ShadowCallStack:%8lu kB\n" #endif "Node %d PageTables: %8lu kB\n" + "Node %d SecPageTables: %8lu kB\n" "Node %d NFS_Unstable: %8lu kB\n" "Node %d Bounce: %8lu kB\n" "Node %d WritebackTmp: %8lu kB\n" @@ -459,6 +460,7 @@ static ssize_t node_read_meminfo(struct device *dev, nid, node_page_state(pgdat, NR_KERNEL_SCS_KB), #endif nid, K(node_page_state(pgdat, NR_PAGETABLE)), + nid, K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)), nid, 0UL, nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)), nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)), diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c index 6e89f0e2fd20f..208efd4fa52c7 100644 --- a/fs/proc/meminfo.c +++ b/fs/proc/meminfo.c @@ -115,6 +115,8 @@ static int meminfo_proc_show(struct seq_file *m, void *v) #endif show_val_kb(m, "PageTables: ", global_node_page_state(NR_PAGETABLE)); + show_val_kb(m, "SecPageTables: ", + global_node_page_state(NR_SECONDARY_PAGETABLE)); show_val_kb(m, "NFS_Unstable: ", 0); show_val_kb(m, "Bounce: ", diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index aab70355d64f3..13190d298c986 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -216,6 +216,7 @@ enum node_stat_item { NR_KERNEL_SCS_KB, /* measured in KiB */ #endif NR_PAGETABLE, /* used for pagetables */ + NR_SECONDARY_PAGETABLE, /* secondary pagetables, e.g. kvm shadow pagetables */ #ifdef CONFIG_SWAP NR_SWAPCACHE, #endif diff --git a/mm/memcontrol.c b/mm/memcontrol.c index abec50f31fe64..d8178395215d4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1394,6 +1394,7 @@ static const struct memory_stat memory_stats[] = { { "kernel", MEMCG_KMEM }, { "kernel_stack", NR_KERNEL_STACK_KB }, { "pagetables", NR_PAGETABLE }, + { "sec_pagetables", NR_SECONDARY_PAGETABLE }, { "percpu", MEMCG_PERCPU_B }, { "sock", MEMCG_SOCK }, { "vmalloc", MEMCG_VMALLOC }, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e008a3df0485c..41ba8942ccee6 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5950,7 +5950,8 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) " active_file:%lu inactive_file:%lu isolated_file:%lu\n" " unevictable:%lu dirty:%lu writeback:%lu\n" " slab_reclaimable:%lu slab_unreclaimable:%lu\n" - " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n" + " mapped:%lu shmem:%lu pagetables:%lu\n" + " sec_pagetables:%lu bounce:%lu\n" " kernel_misc_reclaimable:%lu\n" " free:%lu free_pcp:%lu free_cma:%lu\n", global_node_page_state(NR_ACTIVE_ANON), @@ -5967,6 +5968,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) global_node_page_state(NR_FILE_MAPPED), global_node_page_state(NR_SHMEM), global_node_page_state(NR_PAGETABLE), + global_node_page_state(NR_SECONDARY_PAGETABLE), global_zone_page_state(NR_BOUNCE), global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE), global_zone_page_state(NR_FREE_PAGES), @@ -6000,6 +6002,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) " shadow_call_stack:%lukB" #endif " pagetables:%lukB" + " sec_pagetables:%lukB" " all_unreclaimable? %s" "\n", pgdat->node_id, @@ -6025,6 +6028,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) node_page_state(pgdat, NR_KERNEL_SCS_KB), #endif K(node_page_state(pgdat, NR_PAGETABLE)), + K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)), pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ? "yes" : "no"); } diff --git a/mm/vmstat.c b/mm/vmstat.c index 373d2730fcf21..b937eba681d15 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1240,6 +1240,7 @@ const char * const vmstat_text[] = { "nr_shadow_call_stack", #endif "nr_page_table_pages", + "nr_sec_page_table_pages", #ifdef CONFIG_SWAP "nr_swapcached", #endif