From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-m3272.qiye.163.com (mail-m3272.qiye.163.com [220.197.32.72]) (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 002CD4E50BB; Fri, 9 Oct 2026 13:46:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.32.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791553567; cv=none; b=bD867z1CDwlfpbc4agldAKL8Th7adNgYoyzRMeVJjtA4hzDVs2MxxRZF0tW1WfBXusanr/LSaBvn/BcI18p8rNDxPP1yiU3URWyuDYz7djy25mgAjftVFElsoeVR/oRGr8vKOBNF0E1EI87p3fI5zFWpiCT06RuVv753uGeA1S8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791553567; c=relaxed/simple; bh=2MBQJPHhAwvTI0/6SuzIGdNe/4Na6UB7rkA3+fuVzZA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=R/YK0apBQ4LecmpDldZqkn3qR68zr1d+lmFDLrmepAlns88ZJnvAM4akOlr6eyeszolUPXkXe+tkw48NXKdLVmCY7JUSMNDWQgZuRZuyN4cUKbBv7u7+XRykrbn02MdBoem2nkeWgFN1bHhOg5quXookFKlI3N8dptibqHtQp6c= 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=220.197.32.72 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 [218.94.118.90]) by smtp.qiye.163.com (Hmail) with ESMTP id 1fe2901a2; Fri, 9 Oct 2026 19:23:29 +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 4/6] mm/page_owner: add bpf_page_owner_get_nid() kfunc Date: Fri, 9 Oct 2026 19:23:06 +0800 Message-Id: <20261009112308.240769-5-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> 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: 0aa1206765f80229kunmd33b3e054cb287 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVlCTxkdVk5KS09OSkpKTBpCGlYVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJSkNVQk9VSkpDVUJLWVdZFhoPEhUdFFlBWU9LSFVKS0 lPT09IVUpLS1VKQktLWQY+ Extract the NUMA node lookup from read_page_owner() into a shared page_owner_get_nid() helper, and expose it to BPF programs as bpf_page_owner_get_nid(). The nid bitfield layout is build-time configuration, so BPF programs cannot accurately derive it from page->flags. Signed-off-by: Zhen Ni --- kernel/bpf/helpers.c | 1 + mm/page_owner.c | 26 +++++++++++++++----------- mm/page_owner.h | 1 + mm/page_owner_iter.c | 5 +++++ 4 files changed, 22 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 23a2d2d71f4d..3e8afd19a1f4 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -4951,6 +4951,7 @@ 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) +BTF_ID_FLAGS(func, bpf_page_owner_get_nid, KF_SLEEPABLE) #endif BTF_ID_FLAGS(func, __bpf_trap) BTF_ID_FLAGS(func, bpf_strcmp, KF_PERFMON); diff --git a/mm/page_owner.c b/mm/page_owner.c index eb420803a434..43a722678acc 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -711,6 +711,19 @@ void __dump_page_owner(const struct page *page) page_ext_put(page_ext); } +/* + * NUMA node of @page, bypassing PF_POISONED_CHECK() in page_to_nid() to + * avoid VM_BUG_ON on poisoned pages; -1 for poisoned pages. + */ +int page_owner_get_nid(struct page *page) +{ + memdesc_flags_t page_flags = READ_ONCE(page->flags); + + if (page_flags.f == PAGE_POISON_PATTERN) + return -1; + return memdesc_nid(&page_flags); +} + /* * Advance @scan to the next page eligible for page_owner output. * On a hit, fill scan->pfn/page/po_snap and return true; the caller @@ -810,18 +823,9 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) /* Find an allocated page */ while (page_owner_next_eligible(&scan)) { if (state->nid_filter_enabled) { - int nid; - memdesc_flags_t page_flags = - READ_ONCE(scan.page->flags); + int nid = page_owner_get_nid(scan.page); - /* - * Bypass PF_POISONED_CHECK() in page_to_nid() to avoid - * VM_BUG_ON when accessing poisoned pages. - */ - if (page_flags.f == PAGE_POISON_PATTERN) - goto skip_continue; - nid = memdesc_nid(&page_flags); - if (!node_isset(nid, state->nid_filter)) + if (nid < 0 || !node_isset(nid, state->nid_filter)) goto skip_continue; } diff --git a/mm/page_owner.h b/mm/page_owner.h index fda83be69275..c57859d18dc3 100644 --- a/mm/page_owner.h +++ b/mm/page_owner.h @@ -39,6 +39,7 @@ struct page_owner_scan { }; bool page_owner_next_eligible(struct page_owner_scan *scan); +int page_owner_get_nid(struct page *page); /* * mm/page_owner_iter.c diff --git a/mm/page_owner_iter.c b/mm/page_owner_iter.c index 80693d417407..907517a29144 100644 --- a/mm/page_owner_iter.c +++ b/mm/page_owner_iter.c @@ -165,4 +165,9 @@ __bpf_kfunc int bpf_page_owner_stack_snprint(depot_stack_handle_t handle, return stack_depot_snprint(handle, buf, buf_size, 0); } +__bpf_kfunc int bpf_page_owner_get_nid(struct page_owner_scan *scan) +{ + return page_owner_get_nid(scan->page); +} + __bpf_kfunc_end_defs(); -- 2.20.1