From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-m3290.qiye.163.com (mail-m3290.qiye.163.com [220.197.32.90]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96A04477989 for ; Thu, 30 Apr 2026 16:38:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.32.90 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777567109; cv=none; b=awKJJ2+QGlf6ZiMjeztVjWJCzlWhTpHN9xEISRia6T5B8asGIHRwnUixbploTjf3g1BcluKxZ8VMzKhqmJ32GKpzrDfXFKzrqW3loew9DDdYM72ehj0cDmpe+x8bORFz2WAaAPuLyMA9sz7upELBhwRscp85O05zV8UlxSusp/c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777567109; c=relaxed/simple; bh=UrKe8NAaFsT4buJxKHl7+1gwudU0YCtDtXokOczILFg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=MAUpEBFio0cozJmZgJ3ZD5rQr4XDH8nBpa6B8hxuzMbO9rBElOSwIhRcmlH09Wkiu6C37r6MCXC7kmhmFgrpNgqX0TVr1PUe/f8alJGDhJduGe2pbJjSy/fZnGswmZ93IyztIsoagIcke53WYPzZtspzYbRefM4n0KMjnvniA8c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=easystack.cn; spf=pass smtp.mailfrom=easystack.cn; arc=none smtp.client-ip=220.197.32.90 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=easystack.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=easystack.cn Received: from localhost.localdomain (unknown [IPV6:2409:8a20:e24:8c24:8810:8f74:8c26:2]) by smtp.qiye.163.com (Hmail) with ESMTP id 199a96d50; Fri, 1 May 2026 00:33:00 +0800 (GMT+08:00) From: Zhen Ni To: akpm@linux-foundation.org, vbabka@kernel.org Cc: surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zhen Ni Subject: [PATCH v4 2/3] mm/page_owner: add NUMA node filter with nodelist support Date: Fri, 1 May 2026 00:32:46 +0800 Message-Id: <20260430163247.13628-3-zhen.ni@easystack.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20260430163247.13628-1-zhen.ni@easystack.cn> References: <20260430163247.13628-1-zhen.ni@easystack.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9ddf3c8d010229kunm7d32d45d8a84 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVlDThkeVklJH0tMQ0tMSE4YGVYVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJT0tCQUMaSUtBHklPQUMYSU9BQ0NKS0FDHUxPQUMYSU 1BSVlXWRYaDxIVHRRZQVlPS0hVSktJT09PSFVKS0tVSkJLS1kG Add NUMA node filtering functionality to page_owner to allow filtering pages by specific NUMA node(s). This is useful for NUMA-aware memory allocation analysis and debugging. The filter supports flexible nodelist input formats: - Single node: echo "0" > nid - Multiple nodes: echo "0,2,3" > nid - Node range: echo "0-3" > nid - Mixed format: echo "0,2-4,7" > nid - Clear filter: echo > nid (empty string) The implementation uses nodemask_t for efficient multi-node filtering and nodelist_parse() for flexible input parsing. Empty input clears the filter. Note: Access to nid_mask uses plain load/store without locking because nodemask_t is too large (128 bytes) for READ_ONCE/WRITE_ONCE. This is safe for debug use: low-frequency changes and torn reads would only cause temporary inconsistency in debug output. Signed-off-by: Zhen Ni --- Changes in v4: - Remove "-1" support, use empty string to clear filter - Use strncpy_from_user() instead of copy_from_user() - Add concurrency safety documentation for nid_mask access - Rename fops to page_owner_nid_filter_fops for consistency Changes in v3: - Remove READ_ONCE/WRITE_ONCE for nodemask_t (fixes compilation errors) * nodemask_t is a large structure (128 bytes) that triggers compile-time asserts * Direct assignment is safe for this use case - Add comment explaining input length calculation formula * 6 bytes = ",NNNNN" (comma + 5-digit node number) - Simplify "-1" check using kstrtoint() instead of dual strcmp() - Move nodemask_t mask read outside PFN iteration loop for performance * Avoids 128-byte structure copy on each iteration Changes in v2: - Use nodemask_t instead of int to support multiple nodes - Implement nodelist_parse() to support flexible input formats * Single node: "0", "2" * Multiple nodes: "0,2,3" * Ranges: "0-3" * Mixed: "0,2-4,7" - Use %*pbl format for output (e.g., "0-2", "0,2-4,7") - Use dynamic memory allocation (kmalloc) to handle variable-length input - Follow cpuset's max_write_len pattern: (100 + 6 * MAX_NUMNODES) --- mm/page_owner.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) diff --git a/mm/page_owner.c b/mm/page_owner.c index 28766c854d02..68dacf01c822 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -67,10 +67,18 @@ static const char * const page_owner_print_mode_strings[] = { struct page_owner_filter { enum page_owner_print_mode print_mode; + /* + * Access uses plain load/store without locking. + * nodemask_t is too large (128 bytes) for READ_ONCE/WRITE_ONCE. + * Safe for debug use: low-frequency changes, torn reads only cause + * temporary inconsistency in debug output. + */ + nodemask_t nid_mask; }; static struct page_owner_filter owner_filter = { .print_mode = PAGE_OWNER_PRINT_FULL_STACK, + .nid_mask = NODE_MASK_NONE, }; static bool page_owner_enabled __initdata; @@ -687,6 +695,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) struct page_ext *page_ext; struct page_owner *page_owner; depot_stack_handle_t handle; + nodemask_t mask; if (!static_branch_unlikely(&page_owner_inited)) return -EINVAL; @@ -700,6 +709,8 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) pfn++; + mask = owner_filter.nid_mask; + /* Find an allocated page */ for (; pfn < max_pfn; pfn++) { /* @@ -732,6 +743,14 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) if (unlikely(!page_ext)) continue; + /* NUMA node filter using bitmask */ + if (!nodes_empty(mask)) { + int nid = page_to_nid(page); + + if (!node_isset(nid, mask)) + goto ext_put_continue; + } + /* * Some pages could be missed by concurrent allocation or free, * because we don't hold the zone lock. @@ -1054,6 +1073,72 @@ static const struct file_operations page_owner_print_mode_fops = { .llseek = default_llseek, }; +static ssize_t nid_filter_write(struct file *file, + const char __user *buf, + size_t count, loff_t *ppos) +{ + char *kbuf; + nodemask_t mask; + int ret; + + /* + * Limit input size to handle worst-case nodelist (all nodes). + * Worst case per node: ",NNNNN" (comma + 5-digit node number) = 6 bytes. + * Formula: 100 bytes overhead + 6 * MAX_NUMNODES + */ + if (count > (100 + 6 * MAX_NUMNODES)) + return -EINVAL; + + kbuf = kmalloc(count + 1, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + if (strncpy_from_user(kbuf, buf, count) < 0) { + ret = -EFAULT; + goto out_free; + } + kbuf[count] = '\0'; + + /* Support nodelist format like "0", "0,2", "0-3", or empty to clear */ + if (nodelist_parse(kbuf, mask)) { + ret = -EINVAL; + goto out_free; + } + + owner_filter.nid_mask = mask; + ret = count; + +out_free: + kfree(kbuf); + return ret; +} + +static int nid_filter_show(struct seq_file *m, void *v) +{ + nodemask_t mask = owner_filter.nid_mask; + + if (nodes_empty(mask)) + seq_puts(m, "\n"); + else + seq_printf(m, "%*pbl\n", nodemask_pr_args(&mask)); + + return 0; +} + +static int nid_filter_open(struct inode *inode, struct file *file) +{ + return single_open(file, nid_filter_show, NULL); +} + +static const struct file_operations page_owner_nid_filter_fops = { + .owner = THIS_MODULE, + .open = nid_filter_open, + .read = seq_read, + .llseek = seq_lseek, + .write = nid_filter_write, + .release = single_release, +}; + static int __init pageowner_init(void) { @@ -1069,6 +1154,8 @@ static int __init pageowner_init(void) filter_dir = debugfs_create_dir("page_owner_filter", NULL); debugfs_create_file("print_mode", 0600, filter_dir, NULL, &page_owner_print_mode_fops); + debugfs_create_file("nid", 0600, filter_dir, NULL, + &page_owner_nid_filter_fops); dir = debugfs_create_dir("page_owner_stacks", NULL); debugfs_create_file("show_stacks", 0400, dir, -- 2.20.1