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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E9533FF8867 for ; Tue, 28 Apr 2026 03:36:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5931E6B0088; Mon, 27 Apr 2026 23:36:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 543FE6B008A; Mon, 27 Apr 2026 23:36:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4596A6B008C; Mon, 27 Apr 2026 23:36:38 -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 36A566B0088 for ; Mon, 27 Apr 2026 23:36:38 -0400 (EDT) Received: from smtpin16.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id DB01E1A03F8 for ; Tue, 28 Apr 2026 03:36:37 +0000 (UTC) X-FDA: 84706552434.16.C1CD5D5 Received: from mail-m82108.xmail.ntesmail.com (mail-m82108.xmail.ntesmail.com [156.224.82.108]) by imf12.hostedemail.com (Postfix) with ESMTP id 548BA40008 for ; Tue, 28 Apr 2026 03:36:34 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=none; spf=pass (imf12.hostedemail.com: domain of zhen.ni@easystack.cn designates 156.224.82.108 as permitted sender) smtp.mailfrom=zhen.ni@easystack.cn; dmarc=pass (policy=none) header.from=easystack.cn ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1777347395; 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=bIRf47FM4YMXufYG25lYKKrkjhVnziGfGs233nvXfpA=; b=aN8vWyGffKQt53k+wiyQSFgGKUjLVtspyB2E0n+Cpr6NOjMsn4Aq0y+wxw2+PwYooqBjL1 bDI5mcf9d73baXA1VEP3CTqGegnw/p4dSwEhOeHuV7WygyTRcIPrGa7r0vUAjChhsXbGW/ mTyCCU4C26ykQNCnmHdn87Lyjl+CspU= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777347395; a=rsa-sha256; cv=none; b=OkXiz/fmQfZYQIl224S8yUjF9Deq99kxZTh5HiIz4Tk4Jn/T7Jg0WjSCxO8dy3g+XN2Tqa prq4Eg7AgLOPm7DJhf82kIXR9ztYJAgBrdhjRnvzAZNDLi6CspHGRUqS2VEC8CxIm0NpJo cJj21eqW8jbroOolS+n/V2N/yehEGyM= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=none; spf=pass (imf12.hostedemail.com: domain of zhen.ni@easystack.cn designates 156.224.82.108 as permitted sender) smtp.mailfrom=zhen.ni@easystack.cn; dmarc=pass (policy=none) header.from=easystack.cn Received: from [192.168.0.18] (unknown [218.94.118.90]) by smtp.qiye.163.com (Hmail) with ESMTP id 19787b531; Tue, 28 Apr 2026 11:36:30 +0800 (GMT+08:00) Message-ID: <0f9e11c8-743e-45be-8fbc-ea81d7592ae3@easystack.cn> Date: Tue, 28 Apr 2026 11:36:30 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/3] mm/page_owner: add print_mode filter To: Zi Yan Cc: akpm@linux-foundation.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260419155540.376847-1-zhen.ni@easystack.cn> <20260419155540.376847-3-zhen.ni@easystack.cn> <41EDDEC1-9BAB-447D-AAB0-B8B22289F19C@nvidia.com> From: "zhen.ni" In-Reply-To: <41EDDEC1-9BAB-447D-AAB0-B8B22289F19C@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9dd228ecfb0229kunm47e2a607147fff X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVkaH01OVk9CGEsfGRpKGEoZHlYVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJSkNVQk9VSkpDVUJLWVdZFhoPEhUdFFlBWU9LSFVKS0 lPT09IVUpLS1VKQktLWQY+ X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 548BA40008 X-Stat-Signature: ety97844k59ch6bffzccip6zenk8eizx X-Rspam-User: X-HE-Tag: 1777347394-434339 X-HE-Meta: U2FsdGVkX18J9Ek8wZ0Ey9KczaCVSlLyTgIM0TpBQ2IRLIp0TvzUAhMDG8B3jTf8nkX+dAJINRI+RQFfqM2GH1YfaQFleosv1qglaMQH414oWBhL3pyI297w556fp4xxggwmeu8bsS+oJ28LZ6oKDB1X9sCEIPyTAYQitEbx+rXOdg4AruccNXiddqlqoJQvpEuH6P4O/Xkk0g6/Qsq1eQQ/k1x7djvSY84o3jTQ3VYZGT3kjv9Zh8fpnZjzS5+o5BTc6HLeS3e3R7Zr9i+nuttYdzBCjZtWOsKkZaKlo633Vq3nJh34TALLcRnLKdUaK5DkseoV2EuaxI6b4/r73SQIeQRFL2eawRS7wIDSy036wFNKbadO63r8OyaMG/Qwg9F0pT519uTcY8PeQp4UT2qg9di5ii3wmWVl5V6gDdisWTK7e9TqadVFqRKmAxJ5l7r2T2/IWvf+yZpnRX4mAS2ZNtvXykVxn0ZLay0l+rMS6sGu2AtWIGSokuIzhVUpZN36EG0Ul2rvOFVdTpTNyr8LYww/qetZokrqgR5PznhDOffNZNo7lQhTt5rdvjbfNtaTp77bTGl67hVH0THMlEyU8HnRBzVL1l7oIRmtjiZGS2dXziLPqBRwGITxDG9ENmrYDwBEC7n/HI916uGAyAf1Gv478yU7Cemiro1ZBH5Xi0WwqwLmFwwJT//Uo2akLcm+O+cXj7h/M5TJKa32rlU1JC4Keg2L4Yt+lNSCRBfatw+K2Nu7Jf6HThc7Yj4zx1xw6OVYDlFI56UWYvIteMwVIjSvgH6dRg4eszMJHp/kwbUQcNGkR4Gx49NP7LyLW44HexEoUnU5wZ5hDwbkHrBFhFgv1LNNjytTZOmoG3KE+3dnjcLMlXsi35hm8HCnpj2GxjZh/LHL8z26G4R+y/KIeTsvdyaXZ6Qo8i2AZwFBclH/Hx9apGlFgHw63cGJB/ZN3Fk167pUVoJJxmR ycsIv1NM aIlCGXOEtez0Lgf5vYnovtj1GYmv2u7FuDTvYl57VrvVrprsYkzGdzqpRij3AYOvW/qyjeAW8l/JDQgkhkxyAO6XIVgQRyLUT7UWkKQoKtsBZl1bJOTBwIVOGUOkyeoJesxer+Wd/4f16afedHIe7f+rsARIVOIX1oUZsSowWwSV+ivqvVrXuaoQrk6Ou7u4xEWowKEO5pMiZMP2oUmlhNW+2FdvMHllh4qoA3yfVLHSqFxA2UjqBzN+HS80gGOMbJ+jnZcO1+75b74A= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2026/4/27 23:43, Zi Yan 写道: > On 19 Apr 2026, at 11:55, Zhen Ni wrote: > >> 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 > > I think it is more user-friendly to use “full_stack” and “stack_handle” > instead of 0 and 1. You can refer to [1] to sysfs_match_string() to > do that. I was testing the interface, but needed to look at your code > to know which print_mode I am using. ;) > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/tree/mm/huge_memory.c?h=mm-everything#n380 > > Thanks for the suggestion! I considered using "full_stack" and "stack_handle" strings, but I think the numeric values (0/1) are more concise and easier to type for users. The v3 documentation will clarify the meaning: - 0 (default): Print full stack traces - 1: Print only stack handles Do you think this is sufficient, or would you still prefer using string values instead? > Best Regards, > Yan, Zi > > Best regards, Zhen