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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 A40D1C4361B for ; Thu, 10 Dec 2020 11:40:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64BFF23D56 for ; Thu, 10 Dec 2020 11:40:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729976AbgLJLka (ORCPT ); Thu, 10 Dec 2020 06:40:30 -0500 Received: from mx2.suse.de ([195.135.220.15]:59554 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726119AbgLJLk3 (ORCPT ); Thu, 10 Dec 2020 06:40:29 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3E9E4AD75; Thu, 10 Dec 2020 11:39:45 +0000 (UTC) Subject: Re: [PATCH v2 sl-b 3/5] mm: Make mem_dump_obj() handle vmalloc() memory To: paulmck@kernel.org Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, iamjoonsoo.kim@lge.com, andrii@kernel.org, linux-mm@kvack.org References: <20201209011124.GA31164@paulmck-ThinkPad-P72> <20201209011303.32737-3-paulmck@kernel.org> <1c25ca09-ec43-df31-a5ba-476397637a53@suse.cz> <20201209232310.GI2657@paulmck-ThinkPad-P72> From: Vlastimil Babka Message-ID: <576aa539-5f07-97b3-dd3a-8fe6aac5da99@suse.cz> Date: Thu, 10 Dec 2020 11:49:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: <20201209232310.GI2657@paulmck-ThinkPad-P72> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On 12/10/20 12:23 AM, Paul E. McKenney wrote: > On Wed, Dec 09, 2020 at 06:51:20PM +0100, Vlastimil Babka wrote: >> On 12/9/20 2:13 AM, paulmck@kernel.org wrote: >> > From: "Paul E. McKenney" >> > >> > This commit adds vmalloc() support to mem_dump_obj(). Note that the >> > vmalloc_dump_obj() function combines the checking and dumping, in >> > contrast with the split between kmem_valid_obj() and kmem_dump_obj(). >> > The reason for the difference is that the checking in the vmalloc() >> > case involves acquiring a global lock, and redundant acquisitions of >> > global locks should be avoided, even on not-so-fast paths. >> > >> > Note that this change causes on-stack variables to be reported as >> > vmalloc() storage from kernel_clone() or similar, depending on the degree >> > of inlining that your compiler does. This is likely more helpful than >> > the earlier "non-paged (local) memory". >> > >> > Cc: Andrew Morton >> > Cc: Joonsoo Kim >> > Cc: >> > Reported-by: Andrii Nakryiko >> > Signed-off-by: Paul E. McKenney >> >> ... >> >> > --- a/mm/vmalloc.c >> > +++ b/mm/vmalloc.c >> > @@ -3431,6 +3431,18 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) >> > } >> > #endif /* CONFIG_SMP */ >> > >> > +bool vmalloc_dump_obj(void *object) >> > +{ >> > + struct vm_struct *vm; >> > + void *objp = (void *)PAGE_ALIGN((unsigned long)object); >> > + >> > + vm = find_vm_area(objp); >> > + if (!vm) >> > + return false; >> > + pr_cont(" vmalloc allocated at %pS\n", vm->caller); >> >> Would it be useful to print the vm area boundaries too? > > Like this? Yeah, thanks! > I also considered instead using vm->size, but that always seems to include > an extra page, so a 4-page span is listed as having 20480 bytes and a > one-page span is 8192 bytes. This might be more accurate in some sense, > but would be quite confusing to someone trying to compare this size with > that requested in the vmalloc() call. Right. > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit 33e0469c289c2f78e5f0d0c463c8ee3357d273c0 > Author: Paul E. McKenney > Date: Wed Dec 9 15:15:27 2020 -0800 > > mm: Make mem_obj_dump() vmalloc() dumps include start and length > > This commit adds the starting address and number of pages to the vmalloc() > information dumped by way of vmalloc_dump_obj(). > > Cc: Andrew Morton > Cc: Joonsoo Kim > Cc: > Reported-by: Andrii Nakryiko > Suggested-by: Vlastimil Babka > Signed-off-by: Paul E. McKenney > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 7421719..77b1100 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3439,7 +3439,8 @@ bool vmalloc_dump_obj(void *object) > vm = find_vm_area(objp); > if (!vm) > return false; > - pr_cont(" vmalloc allocated at %pS\n", vm->caller); > + pr_cont(" %u-page vmalloc region starting at %#lx allocated at %pS\n", > + vm->nr_pages, (unsigned long)vm->addr, vm->caller); > return true; > } > >