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 7D1F7EE57CA for ; Fri, 8 Sep 2023 06:45:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 865546B009A; Fri, 8 Sep 2023 02:45:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 816556B009F; Fri, 8 Sep 2023 02:45:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6DE8D6B00A0; Fri, 8 Sep 2023 02:45:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 5D7F76B009A for ; Fri, 8 Sep 2023 02:45:09 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 33009A036F for ; Fri, 8 Sep 2023 06:45:09 +0000 (UTC) X-FDA: 81212493138.07.540E7C0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf12.hostedemail.com (Postfix) with ESMTP id 1BB4940016 for ; Fri, 8 Sep 2023 06:45:06 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AWlToVVa; spf=pass (imf12.hostedemail.com: domain of bhe@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=bhe@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1694155507; 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=JBgRp/Pi+WyYWoZu0MQSGlmMdRjI33tn8r0HqLW3EpI=; b=8M4c0uAKYqabq60/UVVCU1hVW/ov+r+FHAGJVnwW7ey1tC6/xf+oIZQWP3Hpw/1IVwMElW 5/wlA2KHWPvAxSjhCg8Y8lCBxKvQR1cTYhQqkx+hm4pEWbLOMUzrGH3DcXKDsTGai/TKPN rhVwhpuM6z7o9VQauNx2KGeFdrqJX30= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1694155507; a=rsa-sha256; cv=none; b=KaJQB1ytZZjdad2jhmQ6EYAaANMgqmPF3DsYaD5ydazckhM6077Vxcj1pDmFOwNxe7Jk/R E7hKk77VZky1ZV/CTrHLF0QC40pw7THyS1VhMLoVvjAD9gcshwxVLNCXX/pZ8RcYXbHB9D xhnE3rUQWM+fR38UfRFAqVWTezBRdmc= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AWlToVVa; spf=pass (imf12.hostedemail.com: domain of bhe@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=bhe@redhat.com; dmarc=pass (policy=none) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694155506; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JBgRp/Pi+WyYWoZu0MQSGlmMdRjI33tn8r0HqLW3EpI=; b=AWlToVVaRvQ40eHysx/0l4mK+U5SHbNkQkoB73B0umSNIEKpoYaDmybeLQukeS/VH2ialD +eSIrW2ZWYJs9O4elf1tOi1OLZsiFw4BljHHwjbgWHuxt7Df01/bVoPRo4DFPMrjqvmWgB E21mFTOqpzd7D21efJliZZHMyU/AYPE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-412-2-3KRVAuPnmAQ5AM-hkugQ-1; Fri, 08 Sep 2023 02:45:01 -0400 X-MC-Unique: 2-3KRVAuPnmAQ5AM-hkugQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E60DD8007CE; Fri, 8 Sep 2023 06:45:00 +0000 (UTC) Received: from localhost (unknown [10.72.112.24]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B49EFD47819; Fri, 8 Sep 2023 06:44:59 +0000 (UTC) Date: Fri, 8 Sep 2023 14:44:56 +0800 From: Baoquan He To: HAGIO =?utf-8?B?S0FaVUhJVE8o6JCp5bC+44CA5LiA5LuBKQ==?= Cc: Uladzislau Rezki , "lijiang@redhat.com" , "linux-mm@kvack.org" , Andrew Morton , LKML , Lorenzo Stoakes , Christoph Hellwig , Matthew Wilcox , "Liam R . Howlett" , Dave Chinner , "Paul E . McKenney" , Joel Fernandes , Oleksiy Avramchenko , "kexec@lists.infradead.org" Subject: Re: [PATCH v2 4/9] mm: vmalloc: Remove global vmap_area_root rb-tree Message-ID: References: <20230829081142.3619-1-urezki@gmail.com> <20230829081142.3619-5-urezki@gmail.com> <8939ea67-ca27-1aa5-dfff-37d78ad59bb8@nec.com> <1d613b25-58d8-375b-6ef4-b27bc9b735e3@nec.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1d613b25-58d8-375b-6ef4-b27bc9b735e3@nec.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Rspamd-Queue-Id: 1BB4940016 X-Rspam-User: X-Stat-Signature: pbx34x89f68y64oftys9tdagys3iuy9x X-Rspamd-Server: rspam03 X-HE-Tag: 1694155506-257692 X-HE-Meta: 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 xO2n/eU/ TEL5aAA/HJqb89tR4rmRsLMWUqxGLtuld7hynP78EPdgTW0xlAWLTQ5ksZEykpgXWEqVJez0AljwiVJX+TsPcnTgxXsI3umLKdxCDxh4axwyHpIvdTnyIxH+DVqIRd4dS4juuDDaWxVs1/M/Yu9poa1GJwhk3rDfVUjj0Y9UazGxLpnIHeqs9INdT1I/hjaCz/CojhnEvmb+y+hOElseRpbmaIJOkfqi/HEQytfy1yYRxDiTSrTxYJNRQ3CvOHKiNTIxCBHcb0wonDKMaTtFw8ay7HDtc0De90llQ8fOIzjuRKu/DgsweUv/vBw== 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 09/08/23 at 05:01am, HAGIO KAZUHITO(萩尾 一仁) wrote: > On 2023/09/08 13:43, Baoquan He wrote: > > On 09/08/23 at 01:51am, HAGIO KAZUHITO(萩尾 一仁) wrote: > >> On 2023/09/07 18:58, Baoquan He wrote: > >>> On 09/07/23 at 11:39am, Uladzislau Rezki wrote: > >>>> On Thu, Sep 07, 2023 at 10:17:39AM +0800, Baoquan He wrote: > >>>>> Add Kazu and Lianbo to CC, and kexec mailing list > >>>>> > >>>>> On 08/29/23 at 10:11am, Uladzislau Rezki (Sony) wrote: > >>>>>> Store allocated objects in a separate nodes. A va->va_start > >>>>>> address is converted into a correct node where it should > >>>>>> be placed and resided. An addr_to_node() function is used > >>>>>> to do a proper address conversion to determine a node that > >>>>>> contains a VA. > >>>>>> > >>>>>> Such approach balances VAs across nodes as a result an access > >>>>>> becomes scalable. Number of nodes in a system depends on number > >>>>>> of CPUs divided by two. The density factor in this case is 1/2. > >>>>>> > >>>>>> Please note: > >>>>>> > >>>>>> 1. As of now allocated VAs are bound to a node-0. It means the > >>>>>> patch does not give any difference comparing with a current > >>>>>> behavior; > >>>>>> > >>>>>> 2. The global vmap_area_lock, vmap_area_root are removed as there > >>>>>> is no need in it anymore. The vmap_area_list is still kept and > >>>>>> is _empty_. It is exported for a kexec only; > >>>>> > >>>>> I haven't taken a test, while accessing all nodes' busy tree to get > >>>>> va of the lowest address could severely impact kcore reading efficiency > >>>>> on system with many vmap nodes. People doing live debugging via > >>>>> /proc/kcore will get a little surprise. > >>>>> > >>>>> > >>>>> Empty vmap_area_list will break makedumpfile utility, Crash utility > >>>>> could be impactd too. I checked makedumpfile code, it relys on > >>>>> vmap_area_list to deduce the vmalloc_start value. > >>>>> > >>>> It is left part and i hope i fix it in v3. The problem here is > >>>> we can not give an opportunity to access to vmap internals from > >>>> outside. This is just not correct, i.e. you are not allowed to > >>>> access the list directly. > >>> > >>> Right. Thanks for the fix in v3, that is a relief of makedumpfile and > >>> crash. > >>> > >>> Hi Kazu, > >>> > >>> Meanwhile, I am thinking if we should evaluate the necessity of > >>> vmap_area_list in makedumpfile and Crash. In makedumpfile, we just use > >>> vmap_area_list to deduce VMALLOC_START. Wondering if we can export > >>> VMALLOC_START directly. Surely, the lowest va->va_start in vmap_area_list > >>> is a tighter low boundary of vmalloc area and can reduce unnecessary > >>> scanning below the lowest va. Not sure if this is the reason people > >>> decided to export vmap_area_list. > >> > >> The kernel commit acd99dbf5402 introduced the original vmlist entry to > >> vmcoreinfo, but there is no information about why it did not export > >> VMALLOC_START directly. > >> > >> If VMALLOC_START is exported directly to vmcoreinfo, I think it would be > >> enough for makedumpfile. > > > > Thanks for confirmation, Kazu. > > > > Then, below draft patch should be enough to export VMALLOC_START > > instead, and remove vmap_area_list. > > also the following entries can be removed. > > VMCOREINFO_OFFSET(vmap_area, va_start); > VMCOREINFO_OFFSET(vmap_area, list); Right, they are useless now. I updated to remove them in below patch. >From a867fada34fd9e96528fcc5e72ae50b3b5685015 Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Fri, 8 Sep 2023 11:53:22 +0800 Subject: [PATCH] mm/vmalloc: remove vmap_area_list Content-type: text/plain Earlier, vmap_area_list is exported to vmcoreinfo so that makedumpfile get the base address of vmalloc area. Now, vmap_area_list is empty, so export VMALLOC_START to vmcoreinfo instead, and remove vmap_area_list. Signed-off-by: Baoquan He --- Documentation/admin-guide/kdump/vmcoreinfo.rst | 8 ++++---- arch/arm64/kernel/crash_core.c | 1 - arch/riscv/kernel/crash_core.c | 1 - include/linux/vmalloc.h | 1 - kernel/crash_core.c | 4 +--- kernel/kallsyms_selftest.c | 1 - mm/nommu.c | 2 -- mm/vmalloc.c | 3 +-- 8 files changed, 6 insertions(+), 15 deletions(-) diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst index 599e8d3bcbc3..c11bd4b1ceb1 100644 --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -65,11 +65,11 @@ Defines the beginning of the text section. In general, _stext indicates the kernel start address. Used to convert a virtual address from the direct kernel map to a physical address. -vmap_area_list --------------- +VMALLOC_START +------------- -Stores the virtual area list. makedumpfile gets the vmalloc start value -from this variable and its value is necessary for vmalloc translation. +Stores the base address of vmalloc area. makedumpfile gets this value +since is necessary for vmalloc translation. mem_map ------- diff --git a/arch/arm64/kernel/crash_core.c b/arch/arm64/kernel/crash_core.c index 66cde752cd74..2a24199a9b81 100644 --- a/arch/arm64/kernel/crash_core.c +++ b/arch/arm64/kernel/crash_core.c @@ -23,7 +23,6 @@ void arch_crash_save_vmcoreinfo(void) /* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */ vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR); vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END); - vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START); vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END); vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", VMEMMAP_START); vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END); diff --git a/arch/riscv/kernel/crash_core.c b/arch/riscv/kernel/crash_core.c index 55f1d7856b54..5c39cedd2c5c 100644 --- a/arch/riscv/kernel/crash_core.c +++ b/arch/riscv/kernel/crash_core.c @@ -9,7 +9,6 @@ void arch_crash_save_vmcoreinfo(void) VMCOREINFO_NUMBER(phys_ram_base); vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", PAGE_OFFSET); - vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START); vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END); vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", VMEMMAP_START); vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END); diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index c720be70c8dd..91810b4e9510 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -253,7 +253,6 @@ extern long vread_iter(struct iov_iter *iter, const char *addr, size_t count); /* * Internals. Don't use.. */ -extern struct list_head vmap_area_list; extern __init void vm_area_add_early(struct vm_struct *vm); extern __init void vm_area_register_early(struct vm_struct *vm, size_t align); diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 03a7932cde0a..a9faaf7e5f7d 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -617,7 +617,7 @@ static int __init crash_save_vmcoreinfo_init(void) VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir); #endif VMCOREINFO_SYMBOL(_stext); - VMCOREINFO_SYMBOL(vmap_area_list); + vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START); #ifndef CONFIG_NUMA VMCOREINFO_SYMBOL(mem_map); @@ -658,8 +658,6 @@ static int __init crash_save_vmcoreinfo_init(void) VMCOREINFO_OFFSET(free_area, free_list); VMCOREINFO_OFFSET(list_head, next); VMCOREINFO_OFFSET(list_head, prev); - VMCOREINFO_OFFSET(vmap_area, va_start); - VMCOREINFO_OFFSET(vmap_area, list); VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1); log_buf_vmcoreinfo_setup(); VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES); diff --git a/kernel/kallsyms_selftest.c b/kernel/kallsyms_selftest.c index b4cac76ea5e9..8a689b4ff4f9 100644 --- a/kernel/kallsyms_selftest.c +++ b/kernel/kallsyms_selftest.c @@ -89,7 +89,6 @@ static struct test_item test_items[] = { ITEM_DATA(kallsyms_test_var_data_static), ITEM_DATA(kallsyms_test_var_bss), ITEM_DATA(kallsyms_test_var_data), - ITEM_DATA(vmap_area_list), #endif }; diff --git a/mm/nommu.c b/mm/nommu.c index 7f9e9e5a0e12..8c6686176ebd 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -131,8 +131,6 @@ int follow_pfn(struct vm_area_struct *vma, unsigned long address, } EXPORT_SYMBOL(follow_pfn); -LIST_HEAD(vmap_area_list); - void vfree(const void *addr) { kfree(addr); diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 50d8239b82df..0a02633a9566 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -729,8 +729,7 @@ EXPORT_SYMBOL(vmalloc_to_pfn); static DEFINE_SPINLOCK(free_vmap_area_lock); -/* Export for kexec only */ -LIST_HEAD(vmap_area_list); + static bool vmap_initialized __read_mostly; /* -- 2.41.0