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imf16.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=easystack.cn; spf=pass (imf16.hostedemail.com: domain of zhen.ni@easystack.cn designates 156.224.82.134 as permitted sender) smtp.mailfrom=zhen.ni@easystack.cn ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777360290; a=rsa-sha256; cv=none; b=SX1RF9CyID/P+lFYwHlRVe42pnSJdXTxcq71aIgJjjBruNNG4yob4aTNOmeUJ5E/xAKNsg ltlt7Sgf21bRLaSlxWktNyC2b+1oYFmb3rtTNHuTc79SKlOEI68q7lGxDrTLqnxSjEnTk7 +JJb8lF1LOXpxJGmZYIiNGz/9vVDLQw= Received: from localhost.localdomain (unknown [218.94.118.90]) by smtp.qiye.163.com (Hmail) with ESMTP id 197b49302; Tue, 28 Apr 2026 15:11:26 +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 v3 2/4] mm/page_owner: add print_mode filter Date: Tue, 28 Apr 2026 15:11:10 +0800 Message-Id: <20260428071112.1420380-3-zhen.ni@easystack.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20260428071112.1420380-1-zhen.ni@easystack.cn> References: <20260428071112.1420380-1-zhen.ni@easystack.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9dd2edb2230229kunmb0c223f1156f19 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVlCTkgdVhgYQkpNHxgeShhIH1YVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJSkNVQk9VSkpDVUJLWVdZFhoPEhUdFFlBWU9LSFVKS0 lPT09IVUpLS1VKQktLWQY+ X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 53435180004 X-Stat-Signature: u1brmbqpk64hohij98domnxghbjwjcx1 X-HE-Tag: 1777360289-582301 X-HE-Meta: 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 CUyDl8pV Qu8ejozIl5wefXBNEl6rvS6S2SXWeWQCmH14Kn6UCs6AQ6sJM/jZWXKgM5HzH779Rhr/qe7CvN7v2WyxBhfiZBGbgpZ8YYEirnTbvSVZQx2bsSXJOAX0aRufYGQ5xHjoIvvnRc32pwMkraH94gr+actFxUspEmjqvSJIGv++as57/lKOhbIK/auY1ewqbA87Stf/s 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' Changes in v3: - No code changes --- 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