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 08EA5C19F2D for ; Tue, 9 Aug 2022 09:30:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242039AbiHIJa4 (ORCPT ); Tue, 9 Aug 2022 05:30:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242167AbiHIJav (ORCPT ); Tue, 9 Aug 2022 05:30:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 74E7FF4 for ; Tue, 9 Aug 2022 02:30:50 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 19FBB60F2B for ; Tue, 9 Aug 2022 09:30:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15779C433C1; Tue, 9 Aug 2022 09:30:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660037449; bh=oKG/HlfgFJO5wLk1gfL3LTkzUR7OvhxkjvEoE0NwXW0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bia3MxU+fd/0wY5vhYRyrJvU5N10BRDJJGq0dWRi0y2QQ6RuYrzT5O1WnBVnI3IuQ IAgRPmvU+HtJ5iJabVEhG0Q5grVNqXwqKKsBSMW613ZH4NsDz7OxcKnz5rcL/GoQVF VgAl3JjckgQ33ugS8kLYY/R+trOxrKGYknJ9v1kHoe9M4k1S3FZoYiVrasCmtPL9qy 85kTXXlnd2s9R9RnlDpHpfWjUpsML9lO7aPOc4VsmrJcRnXu6BqhElyf2Tm39CXAFj fgOGCJNyHtSseEogj8CCAXI3IpQEPP1O74pVbovDfqLJ4neGJalFJ9b4H622PywGE7 iVh9laEA/uuJw== Message-ID: Date: Tue, 9 Aug 2022 11:30:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.0.3 Subject: Re: [PATCH v5] mm/page_owner.c: add llseek for page_owner To: Kassey Li , akpm@linux-foundation.org Cc: minchan@kernel.org, vbabka@suse.cz, iamjoonsoo.kim@lge.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20220809024725.31980-1-quic_yingangl@quicinc.com> Content-Language: en-US From: "Vlastimil Babka (SUSE)" In-Reply-To: <20220809024725.31980-1-quic_yingangl@quicinc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/9/22 04:47, Kassey Li wrote: > There is usage to dump a given cma region page_owner > instead of all page's. > > This change allows to specify a ppos as start_pfn > by fseek. > > Any invalid ppos will be skipped, so it did not > broken the origin dump feature. > > Suggested-by: Vlastimil Babka > Signed-off-by: Kassey Li > --- > Documentation/vm/page_owner.rst | 6 ++++++ > mm/internal.h | 5 +++++ > mm/page_owner.c | 9 ++++++--- > 3 files changed, 17 insertions(+), 3 deletions(-) > > diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst > index f5c954afe97c..8d33d976da8a 100644 > --- a/Documentation/vm/page_owner.rst > +++ b/Documentation/vm/page_owner.rst > @@ -95,6 +95,12 @@ Usage > PFN XXX ... > // Detailed stack > > + By default, it will do full pfn dump, to start with a given pfn, > + page_owner supports fseek. > + > + FILE *fp = fopen("/sys/kernel/debug/page_owner", "r"); > + fseek(fp, pfn_start, SEEK_SET); > + > The ``page_owner_sort`` tool ignores ``PFN`` rows, puts the remaining rows > in buf, uses regexp to extract the page order value, counts the times > and pages of buf, and finally sorts them according to the parameter(s). > diff --git a/mm/internal.h b/mm/internal.h > index c0f8fbe0445b..1ad8f86e6e33 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -189,6 +189,11 @@ extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason > */ > extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address); > > +/* > + * in mm/page_owner.c: This should say where it's defined, not used from, and that's fs/proc/base.c. But it's already declared in fs/proc/internal.h so maybe page_owner.c could just include that header (although it's a bit meh). > + */ > +extern loff_t mem_lseek(struct file *, loff_t, int); > + > /* > * in mm/page_alloc.c > */ > diff --git a/mm/page_owner.c b/mm/page_owner.c > index e4c6f3f1695b..dcbe05e206e1 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -497,8 +497,10 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) > return -EINVAL; > > page = NULL; > - pfn = min_low_pfn + *ppos; > - > + if (*ppos == 0) > + pfn= min_low_pfn; missing space before '=' > + else > + pfn = *ppos; > /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ > while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) > pfn++; > @@ -561,7 +563,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) > continue; > > /* Record the next PFN to read in the file offset */ > - *ppos = (pfn - min_low_pfn) + 1; > + *ppos = pfn + 1; > > return print_page_owner(buf, count, pfn, page, > page_owner, handle); > @@ -660,6 +662,7 @@ static void init_early_allocated_pages(void) > > static const struct file_operations proc_page_owner_operations = { > .read = read_page_owner, > + .llseek = mem_lseek, > }; > > static int __init pageowner_init(void)