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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8744CC3DA4A for ; Fri, 16 Aug 2024 17:03:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 13D058D009C; Fri, 16 Aug 2024 13:03:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0ECBB8D007E; Fri, 16 Aug 2024 13:03:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ECE768D009C; Fri, 16 Aug 2024 13:03:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id CEA698D007E for ; Fri, 16 Aug 2024 13:03:04 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 4B1881601A6 for ; Fri, 16 Aug 2024 17:03:04 +0000 (UTC) X-FDA: 82458728688.21.5C06C27 Received: from mail-lf1-f49.google.com (mail-lf1-f49.google.com [209.85.167.49]) by imf26.hostedemail.com (Postfix) with ESMTP id ECD89140008 for ; Fri, 16 Aug 2024 17:03:01 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="F/pn08c1"; spf=pass (imf26.hostedemail.com: domain of usamaarif642@gmail.com designates 209.85.167.49 as permitted sender) smtp.mailfrom=usamaarif642@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1723827723; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/wE+KRkiKzcFRWf63NMyg9Sx6Q+FLudyGJ004ItKizw=; b=3n1aYMBCRwaoIZlbY6d1dE5MPIBhj9Bi3QAQEC9iasDZoChj9IFS2RqjD2OQvNi1zPEIBD /4lUUAico/EoB3rHzAXwYSgc7q0d43M6ea+FcBwPHRntrpwFF+vaylop+xZ/81grpRJzYw Qhmy+I0EW//bNN13oBdCi0obdnIyuDY= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="F/pn08c1"; spf=pass (imf26.hostedemail.com: domain of usamaarif642@gmail.com designates 209.85.167.49 as permitted sender) smtp.mailfrom=usamaarif642@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1723827723; a=rsa-sha256; cv=none; b=VR0/GOLQInn6p9e45Nc0NdYwT6zwT4rQpEvjkNtCG1TXs8/8UpFoQ8xeYs1yWTWJOGpRws Cw/J7qsyOkpgV4IHOO7pmVXMnc6MN3Gt8fmJFUfT2MzApu2hyLb3v6oku9b6+ecSJDi7gt YyUaI7qStX5P33ivAp9Vc1ekS2q59YM= Received: by mail-lf1-f49.google.com with SMTP id 2adb3069b0e04-52efd8807aaso3007734e87.3 for ; Fri, 16 Aug 2024 10:03:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1723827780; x=1724432580; darn=kvack.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=/wE+KRkiKzcFRWf63NMyg9Sx6Q+FLudyGJ004ItKizw=; b=F/pn08c1UlFjAy+AlVBUPTQa5hzROpTi1FFrHcMJ1VdGxS+T1W3kGWQgW3zZh++jOY H7sVQEjUMLHusaluS1bSYBlt3FZCEpaMEMJFIl6U9pdpG4jytGMbMlfFx5aHqK5B7D14 d9g5US6c/wTKS2FrO87tYeeaGCcB3VxRQ5QpS2Bfe/MkBNYGCveFyzWZaucjr5KWys7t jLbuzKUoSVhFd1UUu5jTyu1ggv8S1LLrAGDernHocyoiDAAx6l1tCA5iT/VYFdSB85WJ EbSNfUleceIK04b/TqNygqy4zQiuzfulUlm3kxtK7q4Nn65LI10V9X+zp/S33bWmCq4O /IwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723827780; x=1724432580; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=/wE+KRkiKzcFRWf63NMyg9Sx6Q+FLudyGJ004ItKizw=; b=fj0LoTlJ2C4TXb0E16mXoHt5SC/77VsC2u1r+21/P6+s39HOD+Y/3ch91J+tiJ0Lj6 PLEsWJ8iLFd14/9s79fM/r6ho8lbZ9c7c3XfqpVz5AALsyF8i2DLVbyoBrn+AmknJd/q YmmeG/WM/f1KuX7ikZD+nc3JqNZ/X/lL4UKDNncQkBz7+1yOpdJHF6XW5bU1bUtqg3KI c5CMVGOjgIJCF2AkWKiktm6x4rqsoWxrTJHy9kizZmrR+UqjMsssdxKE/o56MdiTrsQ1 aIQWM10Pk/XWvJH4wQMyUzKYvGc9s4idHbMvRXlFQ3pbOS7/jDnAN8QlEOV8NSAlD177 dsDg== X-Forwarded-Encrypted: i=1; AJvYcCVRTTiCD/SnY5pQ39OlYDBCnoGd2RYKYOp1j2Ek4vi3JpzDh7lgtwr56gnR5C0deOjxCnU05kxq18AhFcOkc5rx67E= X-Gm-Message-State: AOJu0YyeH8NStolJjiZGZ5xZNpy+Hjgn2RUDDYeTyFfv21ji8mY+8xve w/WsSd5vlYfftLkYQAK/JfFQKDURWBBbG3h20wKg3hLKMDiKfl+b X-Google-Smtp-Source: AGHT+IGrV169cDf/nlnUA5xyuPfV8CKlqf07VoiE+RZIxkXaT3nL/Dt/Hg+uLB19lvfjH13OMaTpQQ== X-Received: by 2002:a05:6512:b20:b0:52f:c833:861a with SMTP id 2adb3069b0e04-5332e07fba3mr72776e87.51.1723827779411; Fri, 16 Aug 2024 10:02:59 -0700 (PDT) Received: from ?IPV6:2a02:6b6f:e750:7600:c5:51ce:2b5:970b? ([2a02:6b6f:e750:7600:c5:51ce:2b5:970b]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-429d877f822sm97393115e9.1.2024.08.16.10.02.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 16 Aug 2024 10:02:59 -0700 (PDT) Message-ID: <403b7f3c-6e5b-4030-ab1c-3198f36e3f73@gmail.com> Date: Fri, 16 Aug 2024 18:02:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/6] mm: free zapped tail pages when splitting isolated thp To: Kairui Song Cc: akpm@linux-foundation.org, linux-mm@kvack.org, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, roman.gushchin@linux.dev, yuzhao@google.com, david@redhat.com, baohua@kernel.org, ryan.roberts@arm.com, rppt@kernel.org, willy@infradead.org, cerasuolodomenico@gmail.com, corbet@lwn.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@meta.com, Shuang Zhai References: <20240813120328.1275952-1-usamaarif642@gmail.com> <20240813120328.1275952-2-usamaarif642@gmail.com> Content-Language: en-US From: Usama Arif In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Stat-Signature: jg71a4gfrpzx4otonb9dk46mty7k447i X-Rspam-User: X-Rspamd-Queue-Id: ECD89140008 X-Rspamd-Server: rspam02 X-HE-Tag: 1723827781-94717 X-HE-Meta: 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 TGCwn17m 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 16/08/2024 17:55, Kairui Song wrote: > On Fri, Aug 16, 2024 at 3:16 AM Usama Arif wrote: >> On 15/08/2024 19:47, Kairui Song wrote: >>> On Tue, Aug 13, 2024 at 8:03 PM Usama Arif wrote: >>>> >>>> From: Yu Zhao >>>> >>>> If a tail page has only two references left, one inherited from the >>>> isolation of its head and the other from lru_add_page_tail() which we >>>> are about to drop, it means this tail page was concurrently zapped. >>>> Then we can safely free it and save page reclaim or migration the >>>> trouble of trying it. >>>> >>>> Signed-off-by: Yu Zhao >>>> Tested-by: Shuang Zhai >>>> Signed-off-by: Usama Arif >>>> Acked-by: Johannes Weiner >>>> --- >>>> mm/huge_memory.c | 27 +++++++++++++++++++++++++++ >>>> 1 file changed, 27 insertions(+) >>> >>> Hi, Usama, Yu >>> >>> This commit is causing the kernel to panic very quickly with build >>> kernel test on top of tmpfs with all mTHP enabled, the panic comes >>> after: >>> >> >> Hi, >> >> Thanks for pointing this out. It is a very silly bug I have introduced going from v1 page version to the folio version of the patch in v3. >> >> Doing below over this patch will fix it: >> >> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> index 907813102430..a6ca454e1168 100644 >> --- a/mm/huge_memory.c >> +++ b/mm/huge_memory.c >> @@ -3183,7 +3183,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, >> >> folio_clear_active(new_folio); >> folio_clear_unevictable(new_folio); >> - if (!folio_batch_add(&free_folios, folio)) { >> + if (!folio_batch_add(&free_folios, new_folio)) { >> mem_cgroup_uncharge_folios(&free_folios); >> free_unref_folios(&free_folios); >> } >> >> >> I will include it in the next revision. >> > > Hi, > > After the fix, I'm still seeing below panic: > [ 24.926629] list_del corruption. prev->next should be > ffffea000491cf88, but was ffffea0006207708. (prev=ffffea000491cfc8) > [ 24.930783] ------------[ cut here ]------------ > [ 24.932519] kernel BUG at lib/list_debug.c:64! > [ 24.934325] Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI > [ 24.936339] CPU: 32 UID: 0 PID: 2112 Comm: gzip Not tainted > 6.11.0-rc3.ptch+ #147 > [ 24.938575] Hardware name: Red Hat KVM/RHEL-AV, BIOS 0.0.0 02/06/2015 > [ 24.940680] RIP: 0010:__list_del_entry_valid_or_report+0xaa/0xc0 > [ 24.942536] Code: 8c ff 0f 0b 48 89 fe 48 c7 c7 f8 9d 51 82 e8 9d > 36 8c ff 0f 0b 48 89 d1 48 89 f2 48 89 fe 48 c7 c7 30 9e 51 82 e8 86 > 36 8c ff <0f> 0b 48 c7 c7 80 9e 51 82 e8 78 36 8c ff 0f 0b 66 0f 1f 44 > 00 00 > [ 24.948418] RSP: 0018:ffffc90005c2b770 EFLAGS: 00010246 > [ 24.949996] RAX: 000000000000006d RBX: ffffea000491cf88 RCX: 0000000000000000 > [ 24.952293] RDX: 0000000000000000 RSI: ffff889ffee1c180 RDI: ffff889ffee1c180 > [ 24.954616] RBP: ffffea000491cf80 R08: 0000000000000000 R09: c0000000ffff7fff > [ 24.956908] R10: 0000000000000001 R11: ffffc90005c2b5a8 R12: ffffc90005c2b954 > [ 24.959253] R13: ffffc90005c2bbc0 R14: ffffc90005c2b7c0 R15: ffffc90005c2b940 > [ 24.961410] FS: 00007fe5a235e740(0000) GS:ffff889ffee00000(0000) > knlGS:0000000000000000 > [ 24.963587] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 24.965112] CR2: 00007fe5a24ddcd0 CR3: 000000010cb40001 CR4: 0000000000770eb0 > [ 24.967037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 24.968933] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 24.970802] PKRU: 55555554 > [ 24.971559] Call Trace: > [ 24.972241] > [ 24.972805] ? __die_body+0x1e/0x60 > [ 24.973756] ? die+0x3c/0x60 > [ 24.974450] ? do_trap+0xe8/0x110 > [ 24.975235] ? __list_del_entry_valid_or_report+0xaa/0xc0 > [ 24.976543] ? do_error_trap+0x65/0x80 > [ 24.977542] ? __list_del_entry_valid_or_report+0xaa/0xc0 > [ 24.978891] ? exc_invalid_op+0x50/0x70 > [ 24.979870] ? __list_del_entry_valid_or_report+0xaa/0xc0 > [ 24.981295] ? asm_exc_invalid_op+0x1a/0x20 > [ 24.982389] ? __list_del_entry_valid_or_report+0xaa/0xc0 > [ 24.983781] shrink_folio_list+0x39a/0x1200 > [ 24.984898] shrink_inactive_list+0x1c0/0x420 > [ 24.986082] shrink_lruvec+0x5db/0x780 > [ 24.987078] shrink_node+0x243/0xb00 > [ 24.988063] ? get_pfnblock_flags_mask.constprop.117+0x1d/0x50 > [ 24.989622] do_try_to_free_pages+0xbd/0x4e0 > [ 24.990732] try_to_free_mem_cgroup_pages+0x107/0x230 > [ 24.992034] try_charge_memcg+0x184/0x5d0 > [ 24.993145] obj_cgroup_charge_pages+0x38/0x110 > [ 24.994326] __memcg_kmem_charge_page+0x8d/0xf0 > [ 24.995531] __alloc_pages_noprof+0x278/0x360 > [ 24.996712] alloc_pages_mpol_noprof+0xf0/0x230 > [ 24.997896] pipe_write+0x2ad/0x5f0 > [ 24.998837] ? __pfx_tick_nohz_handler+0x10/0x10 > [ 25.000234] ? update_process_times+0x8c/0xa0 > [ 25.001377] ? timerqueue_add+0x77/0x90 > [ 25.002257] vfs_write+0x39b/0x420 > [ 25.003083] ksys_write+0xbd/0xd0 > [ 25.003950] do_syscall_64+0x47/0x110 > [ 25.004917] entry_SYSCALL_64_after_hwframe+0x76/0x7e > [ 25.006210] RIP: 0033:0x7fe5a246f784 > [ 25.007149] Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f > 84 00 00 00 00 00 f3 0f 1e fa 80 3d c5 08 0e 00 00 74 13 b8 01 00 00 > 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 > 48 89 > [ 25.011961] RSP: 002b:00007ffdb0057b38 EFLAGS: 00000202 ORIG_RAX: > 0000000000000001 > [ 25.013946] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fe5a246f784 > [ 25.015817] RDX: 0000000000008000 RSI: 0000558c0d311420 RDI: 0000000000000001 > [ 25.017717] RBP: 00007ffdb0057b60 R08: 0000558c0d258c40 R09: 0000558c0d311420 > [ 25.019618] R10: 00007ffdb0057600 R11: 0000000000000202 R12: 0000000000008000 > [ 25.021519] R13: 0000558c0d311420 R14: 0000000000000029 R15: 0000000000001f8d > [ 25.023412] > [ 25.023998] Modules linked in: > [ 25.024900] ---[ end trace 0000000000000000 ]--- > [ 25.026329] RIP: 0010:__list_del_entry_valid_or_report+0xaa/0xc0 > [ 25.027885] Code: 8c ff 0f 0b 48 89 fe 48 c7 c7 f8 9d 51 82 e8 9d > 36 8c ff 0f 0b 48 89 d1 48 89 f2 48 89 fe 48 c7 c7 30 9e 51 82 e8 86 > 36 8c ff <0f> 0b 48 c7 c7 80 9e 51 82 e8 78 36 8c ff 0f 0b 66 0f 1f 44 > 00 00 > [ 25.032525] RSP: 0018:ffffc90005c2b770 EFLAGS: 00010246 > [ 25.033892] RAX: 000000000000006d RBX: ffffea000491cf88 RCX: 0000000000000000 > [ 25.035758] RDX: 0000000000000000 RSI: ffff889ffee1c180 RDI: ffff889ffee1c180 > [ 25.037661] RBP: ffffea000491cf80 R08: 0000000000000000 R09: c0000000ffff7fff > [ 25.039543] R10: 0000000000000001 R11: ffffc90005c2b5a8 R12: ffffc90005c2b954 > [ 25.041426] R13: ffffc90005c2bbc0 R14: ffffc90005c2b7c0 R15: ffffc90005c2b940 > [ 25.043323] FS: 00007fe5a235e740(0000) GS:ffff889ffee00000(0000) > knlGS:0000000000000000 > [ 25.045478] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 25.047013] CR2: 00007fe5a24ddcd0 CR3: 000000010cb40001 CR4: 0000000000770eb0 > [ 25.048935] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 25.050858] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 25.052881] PKRU: 55555554 > [ 25.053634] Kernel panic - not syncing: Fatal exception > [ 25.056902] Kernel Offset: disabled > [ 25.057827] ---[ end Kernel panic - not syncing: Fatal exception ]--- > > If I revert the fix and this patch, the panic is gone, let me know if > I can help debug it. Yes, this is also needed to prevent race with shrink_folio: diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a6ca454e1168..75f5b059e804 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3183,6 +3183,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, folio_clear_active(new_folio); folio_clear_unevictable(new_folio); + list_del(&new_folio->lru); if (!folio_batch_add(&free_folios, new_folio)) { mem_cgroup_uncharge_folios(&free_folios); free_unref_folios(&free_folios); I have tested this so should be ok, but let me know otherwise. I will include this in the next revision I will send soon. Thanks.