From nobody Sat Jun 27 21:24:33 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD0E4C433F5 for ; Sat, 19 Feb 2022 18:05:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242774AbiBSSF7 (ORCPT ); Sat, 19 Feb 2022 13:05:59 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:56688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236954AbiBSSF6 (ORCPT ); Sat, 19 Feb 2022 13:05:58 -0500 Received: from smtpbguseast3.qq.com (smtpbguseast3.qq.com [54.243.244.52]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4467260045 for ; Sat, 19 Feb 2022 10:05:35 -0800 (PST) X-QQ-mid: bizesmtp69t1645293913t7knxfog Received: from localhost.localdomain (unknown [202.96.137.248]) by bizesmtp.qq.com (ESMTP) with id ; Sun, 20 Feb 2022 02:04:52 +0800 (CST) X-QQ-SSF: 01400000000000D0N000B00A0000000 X-QQ-FEAT: l2baldexF9l31JYpc/mQabxD4TJZaEAyqM+u9vrz/2Wzx8oahLNxbfg6cFCMc lzPJluj2xovT7H0ygkSZwoHxQfhVpdLOVe/331kflsGtjCx2zIXpkbiNG4GhgzLdpHO8HMD D0zNVYJfkRKsf+fgHEQobMtYML/JXi62G9T9umb1H+bXhiAHTwyCC4SOlAk0fB8HN2Jp1+D Z2hgID0T+kP5eWQ+8GGdAcCiaHi5u5lCmAZMQN3APk3j3JO08YFYUqNP8UeQLuG6HWZu46x 0tTcQcGkw6bOxmj9o+cgQTqUnUwFOVL5CeVXwWAcF9uvp2ZxtnrozlCNLXDWqAEiFnu7mzm v/JHNdN X-QQ-GoodBg: 2 From: Yixuan Cao To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yixuan Cao Subject: [PATCH] mm/page_owner.c: record tgid Date: Sun, 20 Feb 2022 02:04:50 +0800 Message-Id: <20220219180450.2399-1-caoyixuan2019@email.szu.edu.cn> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:email.szu.edu.cn:qybgforeign:qybgforeign6 X-QQ-Bgrelay: 1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In a single-threaded process, the pid in kernel task_struct is the same as the tgid, which can mark the process of page allocation. But in a multithreaded process, only the task_struct of the thread leader has the same pid as tgid, and the pids of other threads are different from tgid. Therefore, tgid is recorded to provide effective information for debugging and data statistics of multithreaded programs. This can also be achieved by observing the task name (executable file name) for a specific process. However, when the same program is started multiple times, the task name is the same and the tgid is different. Therefore, in the debugging of multi-threaded programs, combined with the task name and tgid, more accurate runtime information of a certain run of the program can be obtained. Signed-off-by: Yixuan Cao --- mm/page_owner.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index d56afa9c792e..0a9588506571 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -31,6 +31,7 @@ struct page_owner { u64 free_ts_nsec; char comm[TASK_COMM_LEN]; pid_t pid; + pid_t tgid; }; =20 static bool page_owner_enabled =3D false; @@ -165,6 +166,7 @@ static inline void __set_page_owner_handle(struct page_= ext *page_ext, page_owner->gfp_mask =3D gfp_mask; page_owner->last_migrate_reason =3D -1; page_owner->pid =3D current->pid; + page_owner->tgid =3D current->tgid; page_owner->ts_nsec =3D local_clock(); strlcpy(page_owner->comm, current->comm, sizeof(page_owner->comm)); @@ -233,6 +235,7 @@ void __folio_copy_owner(struct folio *newfolio, struct = folio *old) old_page_owner->last_migrate_reason; new_page_owner->handle =3D old_page_owner->handle; new_page_owner->pid =3D old_page_owner->pid; + new_page_owner->tgid =3D old_page_owner->tgid; new_page_owner->ts_nsec =3D old_page_owner->ts_nsec; new_page_owner->free_ts_nsec =3D old_page_owner->ts_nsec; strcpy(new_page_owner->comm, old_page_owner->comm); @@ -383,11 +386,11 @@ print_page_owner(char __user *buf, size_t count, unsi= gned long pfn, return -ENOMEM; =20 ret =3D scnprintf(kbuf, count, - "Page allocated via order %u, mask %#x(%pGg), pid %d (%s), ts %llu ns, = free_ts %llu ns\n", + "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts = %llu ns, free_ts %llu ns\n", page_owner->order, page_owner->gfp_mask, &page_owner->gfp_mask, page_owner->pid, - page_owner->comm, page_owner->ts_nsec, - page_owner->free_ts_nsec); + page_owner->tgid, page_owner->comm, + page_owner->ts_nsec, page_owner->free_ts_nsec); =20 /* Print information relevant to grouping pages by mobility */ pageblock_mt =3D get_pageblock_migratetype(page); @@ -454,10 +457,10 @@ void __dump_page_owner(const struct page *page) else pr_alert("page_owner tracks the page as freed\n"); =20 - pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(= %pGg), pid %d (%s), ts %llu, free_ts %llu\n", + pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(= %pGg), pid %d, tgid %d (%s), ts %llu, free_ts %llu\n", page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask, - page_owner->pid, page_owner->comm, page_owner->ts_nsec, - page_owner->free_ts_nsec); + page_owner->pid, page_owner->tgid, page_owner->comm, + page_owner->ts_nsec, page_owner->free_ts_nsec); =20 handle =3D READ_ONCE(page_owner->handle); if (!handle) @@ -669,3 +672,4 @@ static int __init pageowner_init(void) return 0; } late_initcall(pageowner_init) + --=20 2.31.1