From nobody Sat Apr 11 13:58:17 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 19C17ECAAD2 for ; Thu, 1 Sep 2022 04:44:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232903AbiIAEoI (ORCPT ); Thu, 1 Sep 2022 00:44:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232744AbiIAEne (ORCPT ); Thu, 1 Sep 2022 00:43:34 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80359111AFA for ; Wed, 31 Aug 2022 21:43:10 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 20776221E2; Thu, 1 Sep 2022 04:42:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1662007377; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I+9op6+s45dBeDDz0hB6cxjRW0r3Pje/FesTmSW2Zek=; b=NAIeqLSDDSE+P9kHg5Syu0+cXWEM5KdAOu1En/FPsEPWos0BsZE1cBPGZR5MRySX53IHfn wTIcA1u8waN9m0Rh3w/lLxoexge/vWQvCv0TcjSze3peDkowN5nJZecsg+6TI/P3K5tBGs 5iCdzLF5xUjKZuBqvi542DvQpNR+D64= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1662007377; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I+9op6+s45dBeDDz0hB6cxjRW0r3Pje/FesTmSW2Zek=; b=0oalvhcOoaYu6EzaGL2RxZ5vSihBQFyAzeJIJ+GbTXuKLQnsKZUIv00y4F5pN+YHdBNWQo Nqe/TXfpazjOnrCg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 8C293139C4; Thu, 1 Sep 2022 04:42:56 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id IMKAH1A4EGPheAAAMHmgww (envelope-from ); Thu, 01 Sep 2022 04:42:56 +0000 From: Oscar Salvador To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Vlastimil Babka , Eric Dumazet , Waiman Long , Suren Baghdasaryan , Oscar Salvador Subject: [PATCH 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counter Date: Thu, 1 Sep 2022 06:42:48 +0200 Message-Id: <20220901044249.4624-3-osalvador@suse.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220901044249.4624-1-osalvador@suse.de> References: <20220901044249.4624-1-osalvador@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" We might be only interested in knowing about stacks <-> count relationship, so instead of having to fiddle with page_owner output and screen through pfns, let us add a new file called 'page_owner_stacks' that does just that. By cating such file, we will get all the stacktraces followed by its counter (allocated - freed times), so we can have a more specific overview. Signed-off-by: Oscar Salvador Reported-by: kernel test robot --- include/linux/stackdepot.h | 2 ++ lib/stackdepot.c | 40 ++++++++++++++++++++++++++++++++++++++ mm/page_owner.c | 30 ++++++++++++++++++++++++++++ 3 files changed, 72 insertions(+) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 5ee0cf5be88f..20f62039f23a 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -25,6 +25,8 @@ depot_stack_handle_t __stack_depot_save(unsigned long *en= tries, gfp_t gfp_flags, bool can_alloc, stack_action_t action); void stack_depot_dec_count(depot_stack_handle_t handle); +int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos, + unsigned long *last_stack); =20 /* * Every user of stack depot has to call stack_depot_init() during its own= init diff --git a/lib/stackdepot.c b/lib/stackdepot.c index aeb59d3557e2..3090ae0f3958 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -526,3 +526,43 @@ depot_stack_handle_t stack_depot_save_action(unsigned = long *entries, return __stack_depot_save(entries, nr_entries, alloc_flags, true, action); } EXPORT_SYMBOL_GPL(stack_depot_save_action); + +int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos, + unsigned long *last_stack) +{ + struct stack_record *stack =3D NULL, *last; + struct stack_record **stacks; + int i =3D *pos, ret =3D 0; + + /* Continue from the last week if we have one */ + if (*last_stack) { + last =3D (struct stack_record *)*last_stack; + stack =3D last->next; + } else { +new_table: + stacks =3D &stack_table[i]; + stack =3D (struct stack_record *)stacks; + } + + for (; stack; stack =3D stack->next) { + if (!stack->size || stack->size < 0 || + stack->size > size || stack->handle.valid !=3D 1 || + refcount_read(&stack->count) < 1) + continue; + + ret +=3D stack_trace_snprint(buf, size, stack->entries, stack->size, 0); + ret +=3D scnprintf(buf + ret, size - ret, "stack count: %d\n\n", + refcount_read(&stack->count)); + *last_stack =3D (unsigned long)stack; + return ret; + } + + i++; + *pos =3D i; + + /* Keep looking all tables for valid stacks */ + if (i < STACK_HASH_SIZE) + goto new_table; + + return 0; +} diff --git a/mm/page_owner.c b/mm/page_owner.c index 794f346d7520..8c67c7eb2451 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -43,6 +43,8 @@ static depot_stack_handle_t early_handle; =20 static void init_early_allocated_pages(void); =20 +static unsigned long last_stack =3D 0; + static int __init early_page_owner_param(char *buf) { int ret =3D kstrtobool(buf, &page_owner_enabled); @@ -663,6 +665,32 @@ static void init_early_allocated_pages(void) init_zones_in_node(pgdat); } =20 +static ssize_t read_page_owner_stacks(struct file *file, char __user *buf, + size_t count, loff_t *pos) +{ + char *kbuf; + int ret =3D 0; + + count =3D min_t(size_t, count, PAGE_SIZE); + kbuf =3D kmalloc(count, GFP_KERNEL); + if (!kbuf) + return ENOMEM; + + ret +=3D stack_depot_print_stacks_threshold(kbuf, count, pos, &last_stack= ); + if (copy_to_user(buf, kbuf, ret)) + ret =3D -EFAULT; + + if (!ret) + last_stack =3D 0; + + kfree(kbuf); + return ret; +} + +static const struct file_operations proc_page_owner_stacks =3D { + .read =3D read_page_owner_stacks, +}; + static const struct file_operations proc_page_owner_operations =3D { .read =3D read_page_owner, }; @@ -676,6 +704,8 @@ static int __init pageowner_init(void) =20 debugfs_create_file("page_owner", 0400, NULL, NULL, &proc_page_owner_operations); + debugfs_create_file("page_owner_stacks", 0400, NULL, NULL, + &proc_page_owner_stacks); =20 return 0; } --=20 2.35.3