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s=arc-20220608; d=hostedemail.com; t=1776614163; a=rsa-sha256; cv=none; b=AI2Czo75RRQAOdloh037V4PhGFGxCsD5KD54YUhv3ZVPigbKc1VSRE1GNGReG+bKgHtJd3 uyBzGsfCjjOWyrYN5pvp3EZyhEx3Hft9UZ5hpHNMAbNmH4cnV03zr7mjJhPXKwBQlveEJ8 IdB3RRD6mVtn9aIluO58xWyBRghdahA= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of zhen.ni@easystack.cn designates 156.224.82.145 as permitted sender) smtp.mailfrom=zhen.ni@easystack.cn; dmarc=pass (policy=none) header.from=easystack.cn Received: from localhost.localdomain (unknown [IPV6:2409:8a20:ef7:a5b4:8810:8f74:8c26:2]) by smtp.qiye.163.com (Hmail) with ESMTP id 1918e52ab; Sun, 19 Apr 2026 23:55:57 +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 v2 2/3] mm/page_owner: add print_mode filter Date: Sun, 19 Apr 2026 23:55:39 +0800 Message-Id: <20260419155540.376847-3-zhen.ni@easystack.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20260419155540.376847-1-zhen.ni@easystack.cn> References: <20260419155540.376847-1-zhen.ni@easystack.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9da674ada00229kunma1b4aa74234e8f X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWS1ZQUlXWQ8JGhUIEh9ZQVkaHUwZVkJDShoeGkMYSEgfQ1YVFAkWGhdVGRETFh oSFyQUDg9ZV1kYEgtZQVlJT0tCQUMaSUtBHh1MQRpOGU9BQ0NKS0FDHUxPQUMYSU1BSVlXWRYaDx IVHRRZQVlPS0hVSktJT09PSFVKS0tVSkJLS1kG X-Rspamd-Queue-Id: A929D120006 X-Rspamd-Server: rspam07 X-Stat-Signature: z6mi6cx7bgaqb8zyxmzjjfn948qixeuz X-Rspam-User: X-HE-Tag: 1776614162-265256 X-HE-Meta: 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 /0eLWLfC 3COCWglffgfpX4V+UNr4iT2KGw66AVikBUeOzBqa/6raSQYw4wthZG6OmW4DEg63+lnAy7gdz6m9Y3Vk61xY1F222bOaML3blPcMvLgpLkXlKenUuFcu20wUOyStaHwFR99G3tlnLLfmtHMYPsF0W8eNB0VUu+5umV9r0KYAIJ7VZ3UT3d2SEIsyAjOOR3m42bcwsDywhixQIqxBIKombzmrNMw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add print_mode functionality to reduce page_owner output size by printing only the stack handle instead of the full stack trace. Example output with print_mode enabled: Page allocated via order 0, mask 0x42800(GFP_NOWAIT|__GFP_COMP), pid 1, tgid 1 (systemd), ts 349667370 ns PFN 0xa00a2 type Unmovable Block 1280 type Unmovable Flags 0x33fffe0000004124(referenced|lru|active|private|node=3|zone=0| lastcpupid=0x1ffff) handle: 17432583 Charged to memcg / Print mode significantly reduces output size while preserving all other page allocation information. The correspondence between handles and stack traces can be obtained through the show_stacks_handles interface. Link: https://lore.kernel.org/linux-mm/20260417154638.22370-3-zhen.ni@easystack.cn/ Suggested-by: Zi Yan Signed-off-by: Zhen Ni --- Changes in v2: - Renamed from 'compact mode' to 'print_mode' for better clarity - Use enum values (0=full_stack, 1=stack_handle) instead of boolean - Update debugfs filename from 'compact' to 'print_mode' --- mm/page_owner.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index 5884d883837e..6d87b6948cfa 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -590,7 +590,13 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, migratetype_names[pageblock_mt], &page->flags); - ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0); + /* Print mode: full stack or stack handle */ + if (READ_ONCE(owner_filter.print_mode) == PAGE_OWNER_PRINT_STACK_HANDLE) { + ret += scnprintf(kbuf + ret, count - ret, + "handle: %d\n", handle); + } else { + ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0); + } if (ret >= count) goto err; @@ -985,6 +991,24 @@ static int page_owner_threshold_set(void *data, u64 val) DEFINE_SIMPLE_ATTRIBUTE(page_owner_threshold_fops, &page_owner_threshold_get, &page_owner_threshold_set, "%llu"); +static int page_owner_print_mode_get(void *data, u64 *val) +{ + *val = READ_ONCE(owner_filter.print_mode); + return 0; +} + +static int page_owner_print_mode_set(void *data, u64 val) +{ + if (val > PAGE_OWNER_PRINT_STACK_HANDLE) + return -EINVAL; + WRITE_ONCE(owner_filter.print_mode, val); + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(page_owner_print_mode_fops, + &page_owner_print_mode_get, + &page_owner_print_mode_set, "%lld"); + static int __init pageowner_init(void) { @@ -998,6 +1022,8 @@ static int __init pageowner_init(void) debugfs_create_file("page_owner", 0400, NULL, NULL, &page_owner_fops); filter_dir = debugfs_create_dir("page_owner_filter", NULL); + debugfs_create_file("print_mode", 0600, filter_dir, NULL, + &page_owner_print_mode_fops); dir = debugfs_create_dir("page_owner_stacks", NULL); debugfs_create_file("show_stacks", 0400, dir, -- 2.20.1