From patchwork Tue Aug 23 00:46:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 12951582 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 C277BC38142 for ; Tue, 23 Aug 2022 00:46:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239153AbiHWAqu (ORCPT ); Mon, 22 Aug 2022 20:46:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239137AbiHWAqr (ORCPT ); Mon, 22 Aug 2022 20:46:47 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CBE84D142 for ; Mon, 22 Aug 2022 17:46:45 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id c135-20020a624e8d000000b0053617082770so3510756pfb.8 for ; Mon, 22 Aug 2022 17:46:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc; bh=aTqOOrhDjNGrczvh75CpWoUm/AlvC3yVYYZPgju1gz4=; b=pXpZT++K8DSh8CrpE88bDd2s9QCwpXUmdC8Q71nbMw/fdS3P100RroWtZApbjDzm91 5GFWWL/WWAznOCH5txVbs/Fo9NJquBLuvicIqga0F5b5FQkQ4DSDKnSt76CCoJuOgZx8 RD7F4h2OwduHtLpQoYAsHPXRAb9CsZQV9Ttqwfrt4I2kLL7OxZ6AvVL8pLhZNrh7ovev aGdq2g5Qv9ZdGaWE2sySW/kYgYOOxfMhsstH1ApFSbJzSXnMux7XmMPGoSdnQ94+Blg2 j5bQcCj+oTyevUftRoLGIelQL9gvFcjyGfy/JDZ00apDy8Yf4Iw2ghXF94RQGJiZV97D yu5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc; bh=aTqOOrhDjNGrczvh75CpWoUm/AlvC3yVYYZPgju1gz4=; b=PzVQAHbUBFJFDAr5uPVg4K1tuC1WooYh5w+FUDGChsbNxUyaYU6WVL9dO0l7ssLTDY cI9cRlqHzBcQrDdfzWynddDS36BLNCioIdDJ55rrBGz1M7YkGZBIjxCzXHYPaiA5rL61 NbbuQprawqsrAPdIvZyhGS2QMpBRSUXqI/KxyswX6QyzEzpgmgEAz5KCHMCdRs7TFjLs OfzZFBiwKXlSkAuOwarJYYzSGk0I0z4eB+ZiT4hTAFiOdYlKhcTkNCBnZgYspfx5aZC3 d0BM6Fym++/rNVvS7A9iS7g1PY2dAHfoOWKWLmPT1g8a12pg/sOgmsHbVaUKROVpf5vR Qm4A== X-Gm-Message-State: ACgBeo3sf1z/XToX8JnUIhQdAnrsFoKiLDG04+Kg47zh4+jYJsTxPLaX 2AKxRjqsdEefjJflsDdlz+JvHyiI0nwGLET2 X-Google-Smtp-Source: AA6agR4p28DPzj9ExsS2Do4KRWnzMXTkFyALmrLotL9MAVApSZ2yKp+uFsrbdItqJaP/8HP8tjX/f3YbvvKwPZui X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a17:90b:3d90:b0:1fb:151b:b5cb with SMTP id pq16-20020a17090b3d9000b001fb151bb5cbmr878886pjb.210.1661215605157; Mon, 22 Aug 2022 17:46:45 -0700 (PDT) Date: Tue, 23 Aug 2022 00:46:36 +0000 In-Reply-To: <20220823004639.2387269-1-yosryahmed@google.com> Message-Id: <20220823004639.2387269-2-yosryahmed@google.com> Mime-Version: 1.0 References: <20220823004639.2387269-1-yosryahmed@google.com> X-Mailer: git-send-email 2.37.1.595.g718a3a8f04-goog Subject: [PATCH v7 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 be4a77baf784..7ce8130a8924 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1355,6 +1355,11 @@ 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 e7aafc82be99..898c99eae8e4 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -982,6 +982,7 @@ 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 @@ -1090,6 +1091,9 @@ 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 eb0f43784c2b..432d40a5f910 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 6e89f0e2fd20..208efd4fa52c 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 e24b40c52468..355d842d2731 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 pagetables */ #ifdef CONFIG_SWAP NR_SWAPCACHE, #endif diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b69979c9ced5..9d054e3767ce 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1401,6 +1401,7 @@ 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 e5486d47406e..90461bd94744 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6039,7 +6039,8 @@ 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), @@ -6056,6 +6057,7 @@ 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), @@ -6089,6 +6091,7 @@ 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, @@ -6114,6 +6117,7 @@ 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 373d2730fcf2..b937eba681d1 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