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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 BAAB0C48BC2 for ; Wed, 23 Jun 2021 17:34:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5E43F611CB for ; Wed, 23 Jun 2021 17:34:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E43F611CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 52ACF6B0011; Wed, 23 Jun 2021 13:34:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4DA6D6B005D; Wed, 23 Jun 2021 13:34:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 32ED96B006C; Wed, 23 Jun 2021 13:34:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0146.hostedemail.com [216.40.44.146]) by kanga.kvack.org (Postfix) with ESMTP id EF6C86B0011 for ; Wed, 23 Jun 2021 13:34:42 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3156C1BCC9 for ; Wed, 23 Jun 2021 17:34:43 +0000 (UTC) X-FDA: 78285688446.05.17D4916 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf25.hostedemail.com (Postfix) with ESMTP id C185A60019D6 for ; Wed, 23 Jun 2021 17:34:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624469682; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=82l7b5mph8aViFGBqr97Zc7YWOX6QRR3iD1HvNwnDpc=; b=hspezNS0LumAsQSR75oS4KhcQcQRdTzL4rWOWXtWdGiRFZZWKMOg7nEFIaUvg/tq8wtDla +MzJFQuYuWXDW+BQPvcWvOYcKYC+KVD85B5K4WGMMDQ1hZJVhlUn51PdDJyW1w6/zTeBtu FWAyM9Mv9gdy5iPUM9OJ3OeAtE8ColQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-512-9bCgQpL_N7GkIrBmfyO0-w-1; Wed, 23 Jun 2021 13:34:38 -0400 X-MC-Unique: 9bCgQpL_N7GkIrBmfyO0-w-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 82E6F19057A2; Wed, 23 Jun 2021 17:34:37 +0000 (UTC) Received: from optiplex-fbsd (unknown [10.3.128.11]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 15C5E5D6D7; Wed, 23 Jun 2021 17:34:35 +0000 (UTC) Date: Wed, 23 Jun 2021 13:34:33 -0400 From: Rafael Aquini To: Uladzislau Rezki Cc: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: vmalloc: add cond_resched() in __vunmap() Message-ID: References: <20210622225030.478384-1-aquini@redhat.com> <20210623112704.GA1911@pc638.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210623112704.GA1911@pc638.lan> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C185A60019D6 Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=hspezNS0; spf=none (imf25.hostedemail.com: domain of aquini@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=aquini@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Stat-Signature: 1q3iuoa9qzig9kurmn1hz9z5466nuuef X-HE-Tag: 1624469682-243104 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: On Wed, Jun 23, 2021 at 01:27:04PM +0200, Uladzislau Rezki wrote: > > On non-preemptible kernel builds the watchdog can complain > > about soft lockups when vfree() is called against large > > vmalloc areas: > > > > [ 210.851798] kvmalloc-test: vmalloc(2199023255552) succeeded > > [ 238.654842] watchdog: BUG: soft lockup - CPU#181 stuck for 26s! [rmmod:5203] > > [ 238.662716] Modules linked in: kvmalloc_test(OE-) ... > > [ 238.772671] CPU: 181 PID: 5203 Comm: rmmod Tainted: G S OE 5.13.0-rc7+ #1 > > [ 238.781413] Hardware name: Intel Corporation PURLEY/PURLEY, BIOS PLYXCRB1.86B.0553.D01.1809190614 09/19/2018 > > [ 238.792383] RIP: 0010:free_unref_page+0x52/0x60 > > [ 238.797447] Code: 48 c1 fd 06 48 89 ee e8 9c d0 ff ff 84 c0 74 19 9c 41 5c fa 48 89 ee 48 89 df e8 b9 ea ff ff 41 f7 c4 00 02 00 00 74 01 fb 5b <5d> 41 5c c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f0 29 77 > > [ 238.818406] RSP: 0018:ffffb4d87868fe98 EFLAGS: 00000206 > > [ 238.824236] RAX: 0000000000000000 RBX: 000000001da0c945 RCX: ffffb4d87868fe40 > > [ 238.832200] RDX: ffffd79d3beed108 RSI: ffffd7998501dc08 RDI: ffff9c6fbffd7010 > > [ 238.840166] RBP: 000000000d518cbd R08: ffffd7998501dc08 R09: 0000000000000001 > > [ 238.848131] R10: 0000000000000000 R11: ffffd79d3beee088 R12: 0000000000000202 > > [ 238.856095] R13: ffff9e5be3eceec0 R14: 0000000000000000 R15: 0000000000000000 > > [ 238.864059] FS: 00007fe082c2d740(0000) GS:ffff9f4c69b40000(0000) knlGS:0000000000000000 > > [ 238.873089] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 238.879503] CR2: 000055a000611128 CR3: 000000f6094f6006 CR4: 00000000007706e0 > > [ 238.887467] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > [ 238.895433] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > [ 238.903397] PKRU: 55555554 > > [ 238.906417] Call Trace: > > [ 238.909149] __vunmap+0x17c/0x220 > > [ 238.912851] __x64_sys_delete_module+0x13a/0x250 > > [ 238.918008] ? syscall_trace_enter.isra.20+0x13c/0x1b0 > > [ 238.923746] do_syscall_64+0x39/0x80 > > [ 238.927740] entry_SYSCALL_64_after_hwframe+0x44/0xae > > > > Like in other range zapping routines that iterate over > > a large list, lets just add cond_resched() within __vunmap()'s > > page-releasing loop in order to avoid the watchdog splats. > > > > Signed-off-by: Rafael Aquini > > --- > > mm/vmalloc.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > index a13ac524f6ff..cd4b23d65748 100644 > > --- a/mm/vmalloc.c > > +++ b/mm/vmalloc.c > > @@ -2564,6 +2564,7 @@ static void __vunmap(const void *addr, int deallocate_pages) > > > > BUG_ON(!page); > > __free_pages(page, page_order); > > + cond_resched(); > > } > > atomic_long_sub(area->nr_pages, &nr_vmalloc_pages); > > > > -- > > 2.26.3 > > > I have a question about a test case you run to trigger such soft lockup. > > Is that test_vmalloc.sh test-suite or something local? Do you use a huge > vmalloc mappings so high-order pages are used? > Vlad, It's a variant of the simple testcase presented with Kernel Bug 210023: https://bugzilla.kernel.org/show_bug.cgi?id=210023#c7 Cheers, -- Rafael