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 CB541CA6018 for ; Fri, 9 Oct 2026 11:23:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 20C206B0092; Fri, 9 Oct 2026 07:23:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 11AF66B0093; Fri, 9 Oct 2026 07:23:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F23FB6B0095; Fri, 9 Oct 2026 07:23:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id C33B26B0093 for ; Fri, 9 Oct 2026 07:23:36 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 5384E160348 for ; Fri, 9 Oct 2026 11:23:36 +0000 (UTC) X-FDA: 85302852432.08.ED54D47 Received: from mail-m1602365228.xmail.ntesmail.com (mail-m1602365228.xmail.ntesmail.com [160.236.52.28]) by imf04.hostedemail.com (Postfix) with ESMTP id 30B3640007 for ; Fri, 9 Oct 2026 11:23:32 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of zhen.ni@easystack.cn designates 160.236.52.28 as permitted sender) smtp.mailfrom=zhen.ni@easystack.cn; dmarc=pass (policy=none) header.from=easystack.cn ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1791545014; b=4bPWDpenrKHL1PMfp0z2q84g8xhyg/cfn7rTcp0QJoCZaa8aKEdAFyTC+OnbrArD9UagUQ R59g/v3GEj3a7+fVGr4MVmYEaaGibKI468u57hdyS8dUfejHTR4es2QHLiekAgGJzPAB7L d7E/b/r9TWsSmuC5la7Albdb2bEgXRE= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of zhen.ni@easystack.cn designates 160.236.52.28 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=1791545014; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FUL5e6XiDo/8g1xJlmWxbsgduTWJpPh850hBY8iI+Gg=; b=5W3vpGv7nU97eYlHnN5et+JRja6I0+u/hIgO1lzrPfGJPqQcNnNUh5VOMeOLg3SMPaQHJV uQK9Hbfw4h5WV+2u43qBJ6VotYjbMB0QHxSVneelv3FMub66rKZHKBNB6GaENVb/wfS3iA u3bMY1edHAlUdAEvVmfWvORw2TyLiVU= Received: from localhost.localdomain (unknown [218.94.118.90]) by smtp.qiye.163.com (Hmail) with ESMTP id 1fe2901a1; Fri, 9 Oct 2026 19:23:28 +0800 (GMT+08:00) From: Zhen Ni To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, memxor@gmail.com, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org, emil@etsalapatis.com, ihor.solodrai@linux.dev, akpm@linux-foundation.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, brendan.jackman@linux.dev, hannes@cmpxchg.org, ziy@nvidia.com, shuah@kernel.org Cc: bpf@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Zhen Ni Subject: [PATCH 3/6] mm/page_owner: add open-coded page_owner iterator Date: Fri, 9 Oct 2026 19:23:05 +0800 Message-Id: <20261009112308.240769-4-zhen.ni@easystack.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20261009112308.240769-1-zhen.ni@easystack.cn> References: <20261009112308.240769-1-zhen.ni@easystack.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0aa12067610e0229kunmd33b3e054cb283 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVkaSBhNVh4aSEtKHUIZTUtLHVYVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJSkNVQk9VSkpDVUJLWVdZFhoPEhUdFFlBWU9LSFVKS0 lPT09IVUpLS1VKQktLWQY+ X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 30B3640007 X-Rspam-User: X-Stat-Signature: qag7kskbyan7npxxkaaf8jkuek79bsag X-HE-Tag: 1791545012-481625 X-HE-Meta: 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 v5wTizC+ dmUxGzhMgPStN9rjD61bMUH5c3AQSBwBiLoaimvzMsij4m2UnJveuXOW/Xdm35T7wRcqAN/98iCf9Da/0uQUH/leq8LfGkI+Xa2H3pyjiiYDUq4I= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add an open-coded bpf_iter over the pages eligible for page_owner output, reusing page_owner_next_eligible(). A sleepable BPF program drives it with bpf_iter_page_owner_new()/next()/destroy(); each next() returns the page_owner_scan. po_snap is copied inside the page_ext RCU window, so the program needs no RCU section when it reads it. Also add bpf_page_owner_stack_snprint(), which renders the stack trace for a stack_depot handle into a caller-provided buffer. Signed-off-by: Zhen Ni --- kernel/bpf/helpers.c | 6 +++++ mm/page_owner_iter.c | 52 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 58 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 712dca5a2c5b..23a2d2d71f4d 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -4946,6 +4946,12 @@ BTF_ID_FLAGS(func, bpf_iter_dmabuf_new, KF_ITER_NEW | KF_SLEEPABLE) BTF_ID_FLAGS(func, bpf_iter_dmabuf_next, KF_ITER_NEXT | KF_RET_NULL | KF_SLEEPABLE) BTF_ID_FLAGS(func, bpf_iter_dmabuf_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) #endif +#ifdef CONFIG_PAGE_OWNER +BTF_ID_FLAGS(func, bpf_iter_page_owner_new, KF_ITER_NEW | KF_SLEEPABLE) +BTF_ID_FLAGS(func, bpf_iter_page_owner_next, KF_ITER_NEXT | KF_RET_NULL | KF_SLEEPABLE) +BTF_ID_FLAGS(func, bpf_iter_page_owner_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) +BTF_ID_FLAGS(func, bpf_page_owner_stack_snprint, KF_SLEEPABLE) +#endif BTF_ID_FLAGS(func, __bpf_trap) BTF_ID_FLAGS(func, bpf_strcmp, KF_PERFMON); BTF_ID_FLAGS(func, bpf_strcasecmp, KF_PERFMON); diff --git a/mm/page_owner_iter.c b/mm/page_owner_iter.c index 33dc9dcd59de..80693d417407 100644 --- a/mm/page_owner_iter.c +++ b/mm/page_owner_iter.c @@ -4,6 +4,7 @@ #include #include #include +#include #include "page_owner.h" @@ -114,3 +115,54 @@ int page_owner_iter_register(void) return bpf_iter_reg_target(&page_owner_iter_reg_info); } + +/* opaque to BPF programs */ +struct bpf_iter_page_owner { + __u64 __opaque[16]; +} __attribute__((aligned(8))); + +struct bpf_iter_page_owner_kern { + struct page_owner_scan scan; +} __attribute__((aligned(8))); + +__bpf_kfunc_start_defs(); + +__bpf_kfunc int bpf_iter_page_owner_new(struct bpf_iter_page_owner *it) +{ + struct bpf_iter_page_owner_kern *kit = (void *)it; + + BUILD_BUG_ON(sizeof(*kit) > sizeof(*it)); + BUILD_BUG_ON(__alignof__(*kit) != __alignof__(*it)); + + kit->scan.pfn = min_low_pfn; + kit->scan.page = NULL; + return 0; +} + +__bpf_kfunc struct page_owner_scan * +bpf_iter_page_owner_next(struct bpf_iter_page_owner *it) +{ + struct bpf_iter_page_owner_kern *kit = (void *)it; + + cond_resched(); + + if (kit->scan.page) + kit->scan.pfn++; + + if (!page_owner_next_eligible(&kit->scan)) + return NULL; + + return &kit->scan; +} + +__bpf_kfunc void bpf_iter_page_owner_destroy(struct bpf_iter_page_owner *it) +{ +} + +__bpf_kfunc int bpf_page_owner_stack_snprint(depot_stack_handle_t handle, + char *buf, u32 buf_size) +{ + return stack_depot_snprint(handle, buf, buf_size, 0); +} + +__bpf_kfunc_end_defs(); -- 2.20.1