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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7F52C54EE9 for ; Mon, 19 Sep 2022 15:24:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229921AbiISPYy (ORCPT ); Mon, 19 Sep 2022 11:24:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229888AbiISPYS (ORCPT ); Mon, 19 Sep 2022 11:24:18 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B074D399E3 for ; Mon, 19 Sep 2022 08:23:25 -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 4ECE3220F3; Mon, 19 Sep 2022 15:23:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1663601004; h=from:from:reply-to: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=UeQYK9kQcV2lMsWl00jt1CfUO8aglWQ+0Wrli3shIR0=; b=ynoRo9QtjqyG0IEWfeb9mwbZY2Uvfp9CsxQkDu3VyXZI1NjKq5m+v/LJ+twe+RQmf2Bfpz kOVNgUHkf1Z2Dsc3JbEvi3ZKlJE21nRHI4GDowl9xa3moNQJw2KRr5TvQv7X4963N7ti+P /GLafWkaKBngYkdbRSh/Re0EpNiZpcU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1663601004; h=from:from:reply-to: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=UeQYK9kQcV2lMsWl00jt1CfUO8aglWQ+0Wrli3shIR0=; b=Po5nn5dBmvHOF4ihHD4McCHOKM57s6AdB3rZWkEVV0jLW0YFsvcFhcF1ueQfRYtoIDuKWV u7/doBcD/UddhcBQ== 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 1792513A96; Mon, 19 Sep 2022 15:23:24 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id feHxBGyJKGM7dwAAMHmgww (envelope-from ); Mon, 19 Sep 2022 15:23:24 +0000 Message-ID: <9440ffc2-cfda-ade0-839c-71e9378193fb@suse.cz> Date: Mon, 19 Sep 2022 17:23:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH v2 3/3] mm,page_owner: Filter out stacks by a threshold counter Content-Language: en-US To: Oscar Salvador , Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Eric Dumazet , Waiman Long , Suren Baghdasaryan , Marco Elver , Andrey Konovalov , Alexander Potapenko References: <20220905031012.4450-1-osalvador@suse.de> <20220905031012.4450-4-osalvador@suse.de> From: Vlastimil Babka In-Reply-To: <20220905031012.4450-4-osalvador@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/5/22 05:10, Oscar Salvador wrote: > We want to be able to filter out the output on a threshold basis, > in this way we can get rid of a lot of noise and focus only on those > stacks which have an allegedly high counter. > > We can control the threshold value by a new file called > 'page_owner_threshold', which is 0 by default. The name could suggest it has to do something with "page_owner" but in fact it only affects "page_owner_stacks". So maybe "page_owner_stacks_threshold" ? But now it's rather long. Or maybe "page_owner_stacks_min_count" ? Also long but maybe the most self-evident? > Signed-off-by: Oscar Salvador > --- > include/linux/stackdepot.h | 3 ++- > lib/stackdepot.c | 6 +++-- > mm/page_owner.c | 51 +++++++++++++++++++++++++++++++++++++- > 3 files changed, 56 insertions(+), 4 deletions(-) > > diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h > index 19d3f8295df8..742038216cd0 100644 > --- a/include/linux/stackdepot.h > +++ b/include/linux/stackdepot.h > @@ -25,7 +25,8 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, > gfp_t gfp_flags, bool can_alloc, > enum stack_depot_action 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); > +int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos, > + unsigned long threshold); > > /* > * 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 a198b2dbe3fb..a31e882853ab 100644 > --- a/lib/stackdepot.c > +++ b/lib/stackdepot.c > @@ -566,7 +566,8 @@ depot_stack_handle_t stack_depot_save_action(unsigned long *entries, > } > EXPORT_SYMBOL_GPL(stack_depot_save_action); > > -int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos) > +int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos, > + unsigned long threshold) > { > int i = *pos, ret = 0; > struct stack_record **stacks, *stack; > @@ -585,7 +586,8 @@ int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos) > for (; stack; stack = stack->next) { > if (!stack->size || stack->size < 0 || > stack->size > size || stack->handle.valid != 1 || > - refcount_read(&stack->count) < 1) > + refcount_read(&stack->count) < 1 || > + refcount_read(&stack->count) < threshold) > continue; > > ret += stack_trace_snprint(buf, size, stack->entries, stack->size, 0); > diff --git a/mm/page_owner.c b/mm/page_owner.c > index d88e6b4aefa0..5b895d347c5f 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -43,6 +43,8 @@ static depot_stack_handle_t early_handle; > > static void init_early_allocated_pages(void); > > +static unsigned long threshold; > + > static int __init early_page_owner_param(char *buf) > { > int ret = kstrtobool(buf, &page_owner_enabled); > @@ -675,7 +677,7 @@ static ssize_t read_page_owner_stacks(struct file *file, char __user *buf, > if (!kbuf) > return -ENOMEM; > > - ret += stack_depot_print_stacks_threshold(kbuf, count, pos); > + ret += stack_depot_print_stacks_threshold(kbuf, count, pos, threshold); > if (copy_to_user(buf, kbuf, ret)) > ret = -EFAULT; > > @@ -683,6 +685,51 @@ static ssize_t read_page_owner_stacks(struct file *file, char __user *buf, > return ret; > } > > +static int page_owner_threshold_show(struct seq_file *p, void *v) > +{ > + seq_printf(p, "%lu\n", threshold); > + return 0; > +} > + > +static ssize_t write_page_owner_threshold(struct file *file, const char __user *buf, > + size_t count, loff_t *pos) > +{ > + char *kbuf; > + int ret = 0; > + > + count = min_t(size_t, count, PAGE_SIZE); > + kbuf = kmalloc(count, GFP_KERNEL); > + if (!kbuf) > + return -ENOMEM; > + > + if (copy_from_user(kbuf, buf, count)) { > + ret = -EFAULT; > + goto out; > + } > + > + kbuf[count - 1] = '\0'; > + > + ret = kstrtoul(kbuf, 10, &threshold); > + > +out: > + kfree(kbuf); > + return ret ? ret : count; > +} > + > +static int open_page_owner_threshold(struct inode *inode, struct file *file) > +{ > + return single_open(file, page_owner_threshold_show, NULL); > +} > + > + > +static const struct file_operations proc_page_owner_threshold = { > + .open = open_page_owner_threshold, > + .read = seq_read, > + .llseek = seq_lseek, > + .write = write_page_owner_threshold, > + .release = single_release, > +}; > + > static const struct file_operations proc_page_owner_stacks = { > .read = read_page_owner_stacks, > }; > @@ -702,6 +749,8 @@ static int __init pageowner_init(void) > &proc_page_owner_operations); > debugfs_create_file("page_owner_stacks", 0400, NULL, NULL, > &proc_page_owner_stacks); > + debugfs_create_file("page_owner_threshold", 0600, NULL, NULL, > + &proc_page_owner_threshold); > > return 0; > }