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 05F06C00144 for ; Mon, 1 Aug 2022 06:06:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2C2B48E0002; Mon, 1 Aug 2022 02:06:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 271848E0001; Mon, 1 Aug 2022 02:06:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 160408E0002; Mon, 1 Aug 2022 02:06:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 082DF8E0001 for ; Mon, 1 Aug 2022 02:06:13 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id B67011407A0 for ; Mon, 1 Aug 2022 06:06:12 +0000 (UTC) X-FDA: 79749988584.24.EDF5969 Received: from out30-131.freemail.mail.aliyun.com (out30-131.freemail.mail.aliyun.com [115.124.30.131]) by imf03.hostedemail.com (Postfix) with ESMTP id 04F1F200F0 for ; Mon, 1 Aug 2022 06:06:09 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R361e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VL1DdLW_1659333965; Received: from 30.97.48.40(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VL1DdLW_1659333965) by smtp.aliyun-inc.com; Mon, 01 Aug 2022 14:06:06 +0800 Message-ID: Date: Mon, 1 Aug 2022 14:06:13 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [RFC V3 PATCH] mm: add last level page table numa info to /proc/pid/numa_pgtable To: Xin Hao , willy@infradead.org Cc: akpm@linux-foundation.org, adobriyan@gmail.com, keescook@chromium.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20220801032704.64356-1-xhao@linux.alibaba.com> From: Baolin Wang In-Reply-To: <20220801032704.64356-1-xhao@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659333972; a=rsa-sha256; cv=none; b=v8YEvRiUp2V8sAcVjJEs50JySjOEDAQ8Jv6btSM60Xy55ic7zUeffFFstCKOC88WYeZrMF CvxseXVmFB8E3cLQ6pUsnEEcvEkrWoenyVDH8SwjzVXKYwVBsCc1OxXXW63sl6dHVXO6bM nM9CaGBBOHFpMyX/HWop7KX/kIpy4Oo= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=none; spf=pass (imf03.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.131 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659333972; 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; bh=vocpjbskbKJdz8ys7FQYnZSfQ/Zai95WbO2AwUfKkEM=; b=pUQfyB8V7IUNIJJx6LFGshQElGMS2cbSSCU/hm/irvgLSfiEsAl5lOIpWqm3emVGg1LzmB ElTvC17rEci6OJodt7E7LRqQARReUVF67BOF5Muy1AqfJTmEa6r/d9ASoKXPTkDFuRgAdx BfL/xKr3E9VwSbrhbXzm1LwI0lJVoUM= Authentication-Results: imf03.hostedemail.com; dkim=none; spf=pass (imf03.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.131 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com X-Stat-Signature: d7xo83ocj8w4mbs4kheymcwxjsejamsn X-Rspamd-Queue-Id: 04F1F200F0 X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1659333969-903799 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: Hi Xin, On 8/1/2022 11:27 AM, Xin Hao wrote: > In many data center servers, the shared memory architectures is > Non-Uniform Memory Access (NUMA), remote numa node data access > often brings a high latency problem, but what we are easy to ignore > is that the page table remote numa access, It can also leads to a > performance degradation. > > So there add a new interface in /proc, This will help developers to > get more info about performance issues if they are caused by cross-NUMA. > > V2 -> V3 > 1, Fix compile warning bug. > > V1 -> V2 > 1, As Matthew Wilcox advise, Simplify the code. > 2, Do some codes format fix. Please move the changes history under your 'Signed-off-by' with '---'. > > V2: https://lore.kernel.org/linux-mm/20220731155223.60238-1-xhao@linux.alibaba.com/ > V1: https://lore.kernel.org/linux-mm/YuVqdcY8Ibib2LJa@casper.infradead.org/T/ > > Reported-by: kernel test robot > Signed-off-by: Xin Hao > --- > fs/proc/base.c | 2 ++ > fs/proc/internal.h | 1 + > fs/proc/task_mmu.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 90 insertions(+) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 8dfa36a99c74..487e82dd3275 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -3224,6 +3224,7 @@ static const struct pid_entry tgid_base_stuff[] = { > REG("maps", S_IRUGO, proc_pid_maps_operations), > #ifdef CONFIG_NUMA > REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations), > + REG("numa_pgtable", S_IRUGO, proc_pid_numa_pgtable_operations), > #endif > REG("mem", S_IRUSR|S_IWUSR, proc_mem_operations), > LNK("cwd", proc_cwd_link), > @@ -3571,6 +3572,7 @@ static const struct pid_entry tid_base_stuff[] = { > #endif > #ifdef CONFIG_NUMA > REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations), > + REG("numa_pgtable", S_IRUGO, proc_pid_numa_pgtable_operations), > #endif > REG("mem", S_IRUSR|S_IWUSR, proc_mem_operations), > LNK("cwd", proc_cwd_link), > diff --git a/fs/proc/internal.h b/fs/proc/internal.h > index 06a80f78433d..e7ed9ef097b6 100644 > --- a/fs/proc/internal.h > +++ b/fs/proc/internal.h > @@ -296,6 +296,7 @@ struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode); > > extern const struct file_operations proc_pid_maps_operations; > extern const struct file_operations proc_pid_numa_maps_operations; > +extern const struct file_operations proc_pid_numa_pgtable_operations; > extern const struct file_operations proc_pid_smaps_operations; > extern const struct file_operations proc_pid_smaps_rollup_operations; > extern const struct file_operations proc_clear_refs_operations; > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 2d04e3470d4c..77b7a49757f5 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -1999,4 +1999,91 @@ const struct file_operations proc_pid_numa_maps_operations = { > .release = proc_map_release, > }; > > +struct pgtable_numa_private { > + struct proc_maps_private proc_maps; > + unsigned long node[MAX_NUMNODES]; > +}; > + > +static int gather_pgtable_numa_stats(pmd_t *pmd, unsigned long addr, > + unsigned long end, struct mm_walk *walk) > +{ > + struct pgtable_numa_private *priv = walk->private; > + struct page *page; > + int nid; > + > + if (pmd_huge(*pmd)) { > + page = virt_to_page(pmd); > + } else { > + page = pmd_page(*pmd); You should validate if the pmd is valid or present before getting the pagetable page. if (pmd_none(*pmd) || !pmd_present(*pmd)) Another issue is I think you should hold the pmd lock to call pmd_page(), since after the validation of pmd_huge(), the pmd entry can be modified by other threads if you did not hold the pmd lock. > + } > + > + nid = page_to_nid(page); > + priv->node[nid]++; > + > + return 0; > +} > + > +static const struct mm_walk_ops show_numa_pgtable_ops = { > + .pmd_entry = gather_pgtable_numa_stats, > +}; > + > +/* > + * Display the page talbe allocated per node via /proc. > + */ > +static int show_numa_pgtable(struct seq_file *m, void *v) > +{ > + struct pgtable_numa_private *numa_priv = m->private; > + struct vm_area_struct *vma = v; > + struct mm_struct *mm = vma->vm_mm; > + struct file *file = vma->vm_file; > + int nid; > + > + if (!mm) > + return 0; > + > + memset(numa_priv->node, 0, sizeof(numa_priv->node)); > + > + seq_printf(m, "%08lx ", vma->vm_start); > + > + if (file) { > + seq_puts(m, " file="); > + seq_file_path(m, file, "\n\t= "); > + } else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) { > + seq_puts(m, " heap"); > + } else if (is_stack(vma)) { > + seq_puts(m, " stack"); > + } > + > + /* mmap_lock is held by m_start */ > + walk_page_vma(vma, &show_numa_pgtable_ops, numa_priv); > + > + for_each_node_state(nid, N_MEMORY) { > + if (numa_priv->node[nid]) > + seq_printf(m, " N%d=%lu", nid, numa_priv->node[nid]); > + } > + seq_putc(m, '\n'); > + > + return 0; > +} > + > +static const struct seq_operations proc_pid_numa_pgtable_op = { > + .start = m_start, > + .next = m_next, > + .stop = m_stop, > + .show = show_numa_pgtable, > +}; > + > +static int pid_numa_pgtable_open(struct inode *inode, struct file *file) > +{ > + return proc_maps_open(inode, file, &proc_pid_numa_pgtable_op, > + sizeof(struct pgtable_numa_private)); > +} > + > +const struct file_operations proc_pid_numa_pgtable_operations = { > + .open = pid_numa_pgtable_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = proc_map_release, > +}; > + > #endif /* CONFIG_NUMA */ > -- > 2.31.0