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 4900CC25B08 for ; Wed, 10 Aug 2022 09:03:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231918AbiHJJDB (ORCPT ); Wed, 10 Aug 2022 05:03:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231908AbiHJJC7 (ORCPT ); Wed, 10 Aug 2022 05:02:59 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26E7786C06 for ; Wed, 10 Aug 2022 02:02:57 -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 B8563352B6; 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Wed, 10 Aug 2022 09:02:55 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 0d9xHD9082LYEQAAMHmgww (envelope-from ); Wed, 10 Aug 2022 09:02:55 +0000 Message-ID: Date: Wed, 10 Aug 2022 11:02:55 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.1.0 Subject: Re: [PATCH v5] mm/page_owner.c: add llseek for page_owner Content-Language: en-US To: Kassey Li , "Vlastimil Babka (SUSE)" , akpm@linux-foundation.org Cc: minchan@kernel.org, iamjoonsoo.kim@lge.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20220809024725.31980-1-quic_yingangl@quicinc.com> <8f64c6d5-940f-f081-7671-53e1507c8051@quicinc.com> From: Vlastimil Babka In-Reply-To: <8f64c6d5-940f-f081-7671-53e1507c8051@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/10/22 03:33, Kassey Li wrote: > > > On 8/9/2022 5:30 PM, Vlastimil Babka (SUSE) wrote: >> 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). > ok, let's do it. Sorry, my suggestion was wrong as the kernel test bot just showed us. mem_lseek() may be unavailable without CONFIG_PROC_FS. The easiest way is you add a page_owner specific one back, but make it correct for SEEK_CUR. Thanks. >> >>> + */ >>> +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 '=' > > my bad, for v6 > > ./scripts/checkpatch.pl > v6-0001-mm-page_owner.c-add-llseek-for-page_owner.patch > total: 0 errors, 0 warnings, 46 lines checked > > v6-0001-mm-page_owner.c-add-llseek-for-page_owner.patch has no obvious > style problems and is ready for submission. >> >>> + 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) >>