From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13C33C2D0A3 for ; Mon, 2 Nov 2020 01:07:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2C02206E5 for ; Mon, 2 Nov 2020 01:07:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604279248; bh=Xqd6/yl+/1mHKEmZeJ5x792mOBjBaVt7Pqoykjripog=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=jLGxxnUjZz3uFs98H3QAtj8r94XqqUAfusl1V3gen2MtpI+cDhmSrhI0afbY39qkN O+OjS9qaaY4kcL7OiGlE/BvvsLzg7U8XzrCPT06jabNLXH9hogc8mlNjz8X8CQdX5m G40IMl5okZON7zwfcRaPEuakcBkEXkm+P9dRuQPU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727409AbgKBBH2 (ORCPT ); Sun, 1 Nov 2020 20:07:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:48736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727335AbgKBBH2 (ORCPT ); Sun, 1 Nov 2020 20:07:28 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7AE32206A4; Mon, 2 Nov 2020 01:07:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604279248; bh=Xqd6/yl+/1mHKEmZeJ5x792mOBjBaVt7Pqoykjripog=; h=Date:From:To:Subject:In-Reply-To:From; b=geeM2f5lPRsKzK1A4aj1KceFwmu/ZTdL9JwoBjRlA8HcgGNzNzh3kkT8NvSA8Ta9r q7WI/9mva9mrDiEMLs19QCpIGpvO00cRQHi/m98lMxTA9i0qjzil4ZfvWx1R5L8zbO hW29L0W9m8uuMNjm//FJnh3nOm0wietOpzAAci0M= Date: Sun, 01 Nov 2020 17:07:27 -0800 From: Andrew Morton To: akpm@linux-foundation.org, almasrymina@google.com, aneesh.kumar@linux.vnet.ibm.com, david@redhat.com, linux-mm@kvack.org, mhocko@kernel.org, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, mprivozn@redhat.com, mst@redhat.com, songmuchun@bytedance.com, stable@vger.kernel.org, tj@kernel.org, torvalds@linux-foundation.org Subject: [patch 02/15] hugetlb_cgroup: fix reservation accounting Message-ID: <20201102010727.6e4pqN4-U%akpm@linux-foundation.org> In-Reply-To: <20201101170656.48abbd5e88375219f868af5e@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Mike Kravetz Subject: hugetlb_cgroup: fix reservation accounting Michal Privoznik was using "free page reporting" in QEMU/virtio-balloon with hugetlbfs and hit the warning below. QEMU with free page hinting uses fallocate(FALLOC_FL_PUNCH_HOLE) to discard pages that are reported as free by a VM. The reporting granularity is in pageblock granularity. So when the guest reports 2M chunks, we fallocate(FALLOC_FL_PUNCH_HOLE) one huge page in QEMU. [ 315.251417] ------------[ cut here ]------------ [ 315.251424] WARNING: CPU: 7 PID: 6636 at mm/page_counter.c:57 page_counter_uncharge+0x4b/0x50 [ 315.251425] Modules linked in: ... [ 315.251466] CPU: 7 PID: 6636 Comm: qemu-system-x86 Not tainted 5.9.0 #137 [ 315.251467] Hardware name: Gigabyte Technology Co., Ltd. X570 AORUS PRO/X570 AORUS PRO, BIOS F21 07/31/2020 [ 315.251469] RIP: 0010:page_counter_uncharge+0x4b/0x50 ... [ 315.251479] Call Trace: [ 315.251485] hugetlb_cgroup_uncharge_file_region+0x4b/0x80 [ 315.251487] region_del+0x1d3/0x300 [ 315.251489] hugetlb_unreserve_pages+0x39/0xb0 [ 315.251492] remove_inode_hugepages+0x1a8/0x3d0 [ 315.251495] ? tlb_finish_mmu+0x7a/0x1d0 [ 315.251497] hugetlbfs_fallocate+0x3c4/0x5c0 [ 315.251519] ? kvm_arch_vcpu_ioctl_run+0x614/0x1700 [kvm] [ 315.251522] ? file_has_perm+0xa2/0xb0 [ 315.251524] ? inode_security+0xc/0x60 [ 315.251525] ? selinux_file_permission+0x4e/0x120 [ 315.251527] vfs_fallocate+0x146/0x290 [ 315.251529] __x64_sys_fallocate+0x3e/0x70 [ 315.251531] do_syscall_64+0x33/0x40 [ 315.251533] entry_SYSCALL_64_after_hwframe+0x44/0xa9 ... [ 315.251542] ---[ end trace 4c88c62ccb1349c9 ]--- Investigation of the issue uncovered bugs in hugetlb cgroup reservation accounting. This patch addresses the found issues. Link: https://lkml.kernel.org/r/20201021204426.36069-1-mike.kravetz@oracle.com Fixes: 075a61d07a8e ("hugetlb_cgroup: add accounting for shared mappings") Cc: Reported-by: Michal Privoznik Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Mike Kravetz Tested-by: Michal Privoznik Acked-by: Michael S. Tsirkin Reviewed-by: Mina Almasry Cc: David Hildenbrand Cc: Michal Hocko Cc: Muchun Song Cc: "Aneesh Kumar K . V" Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton --- mm/hugetlb.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) --- a/mm/hugetlb.c~hugetlb_cgroup-fix-reservation-accounting +++ a/mm/hugetlb.c @@ -648,6 +648,8 @@ retry: } del += t - f; + hugetlb_cgroup_uncharge_file_region( + resv, rg, t - f); /* New entry for end of split region */ nrg->from = t; @@ -660,9 +662,6 @@ retry: /* Original entry is trimmed */ rg->to = f; - hugetlb_cgroup_uncharge_file_region( - resv, rg, nrg->to - nrg->from); - list_add(&nrg->link, &rg->link); nrg = NULL; break; @@ -678,17 +677,17 @@ retry: } if (f <= rg->from) { /* Trim beginning of region */ - del += t - rg->from; - rg->from = t; - hugetlb_cgroup_uncharge_file_region(resv, rg, t - rg->from); - } else { /* Trim end of region */ - del += rg->to - f; - rg->to = f; + del += t - rg->from; + rg->from = t; + } else { /* Trim end of region */ hugetlb_cgroup_uncharge_file_region(resv, rg, rg->to - f); + + del += rg->to - f; + rg->to = f; } } @@ -2443,6 +2442,9 @@ struct page *alloc_huge_page(struct vm_a rsv_adjust = hugepage_subpool_put_pages(spool, 1); hugetlb_acct_memory(h, -rsv_adjust); + if (deferred_reserve) + hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h), + pages_per_huge_page(h), page); } return page; _