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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 66A49CCA471 for ; Sat, 4 Oct 2025 03:06:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BC16C8E0009; Fri, 3 Oct 2025 23:06:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B98FF8E0002; Fri, 3 Oct 2025 23:06:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD5ED8E0009; Fri, 3 Oct 2025 23:06:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 9EB838E0002 for ; Fri, 3 Oct 2025 23:06:19 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 4F6BD8820D for ; Sat, 4 Oct 2025 03:06:19 +0000 (UTC) X-FDA: 83958943278.23.E24F759 Received: from out-178.mta1.migadu.com (out-178.mta1.migadu.com [95.215.58.178]) by imf24.hostedemail.com (Postfix) with ESMTP id 7C482180011 for ; Sat, 4 Oct 2025 03:06:17 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=QFiiD5fQ; spf=pass (imf24.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1759547177; h=from:from:sender:reply-to:subject:subject: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:dkim-signature; bh=PXNNFB9m2tpLPVfzBH/OyS3UoK141cw9zK+ucGD3NqE=; b=HOO/CU7KcoiJourn6b5iPY7q2S+pzO1SWfLGArJ7PohjRxj3yaBWvVLVbIl8z0yFSeEB+c 9JcdlB+3zm+Eoy57swUr9U10s+NYyTMdjUeLJ5J4K9JzdJbCdwr9+Y55NVZKRq97h2W4OA cfj4/qgSzWEuXaikUrsuURwygJeV34A= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759547177; a=rsa-sha256; cv=none; b=1KMkDyCClYqKSc3n5ljGKNsTVbl6msIE1gquhU5pT0wH49hqjyUlGtAH36cCQGJGXT4YAc 7mfYRTWEpz1uXRaJrDkj/+nkqRncMPR7FkA9PV2+6hmuMFmAAO8p69cHURZX7u3KHjjZc4 GDWGsJMy/vwvaPMM+YOr6EpY8u7PG6Q= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=QFiiD5fQ; spf=pass (imf24.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1759547176; h=from:from:reply-to:subject:subject: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=PXNNFB9m2tpLPVfzBH/OyS3UoK141cw9zK+ucGD3NqE=; b=QFiiD5fQfK8Dx7oW/mtMnx22p7DIXuSnRzi9FM6gwKqugyl7A35FGw56L/dJgRpG2TgTXT aGtDUze/msQHXXHOCfRz7nNPrM49gbEwx16cXMq+1VT1oWJUyDDPcR3g0uw3T3VHVA2Td9 3osGwZBkPG/d+s1POuCdUAQvCZEcSyU= Date: Sat, 4 Oct 2025 11:06:02 +0800 MIME-Version: 1.0 Subject: Re: [PATCH mm-new 2/2] mm/khugepaged: merge PTE scanning logic into a new helper Content-Language: en-US To: Zi Yan Cc: akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, ioworker0@gmail.com, richard.weiyang@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20251002073255.14867-1-lance.yang@linux.dev> <20251002073255.14867-3-lance.yang@linux.dev> <9DF437D8-E98B-4061-A8C7-521D89070C97@nvidia.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <9DF437D8-E98B-4061-A8C7-521D89070C97@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: wfmu4tr9ruh4wyo3zexuhydydsibat3z X-Rspam-User: X-Rspamd-Queue-Id: 7C482180011 X-Rspamd-Server: rspam10 X-HE-Tag: 1759547177-124041 X-HE-Meta: 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 FMYZxsMz jblCdvsjj3i5N2ghRIG3m8zI5qc0nrIrFHBpYOrj4FvV37V9jnifbaLsp2GjpTbouclkqz9QLIdJvPHo2tTzKJEtNxLDcXTpk5JrhGl9x10jKwJmBxlzquPYw6341KxHY6vpjI7Uxxte4jA87nOcms4vqHt+bdhc5S1X3N4Gof69TklmoJodfaKWPabVtuhRJWqRLBQozER706DNZVNQ9q7z92l5Is99Cl+wRD6263uqy+wz+N+ksB1lO1PacjUnhdczvYW9amvRIEZO1d/ofqowWDL0/Sk8BH9Q+QNzrdKYm5eh+YcTvGGF+Aevaox7OytBcbCANyhJQ9sVIs8C5uoeolQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025/10/4 01:11, Zi Yan wrote: > On 2 Oct 2025, at 3:32, Lance Yang wrote: > >> From: Lance Yang >> >> As David suggested, the PTE scanning logic in hpage_collapse_scan_pmd() >> and __collapse_huge_page_isolate() was almost duplicated. >> >> This patch cleans things up by moving all the common PTE checking logic >> into a new shared helper, thp_collapse_check_pte(). >> >> Suggested-by: David Hildenbrand >> Signed-off-by: Lance Yang >> --- >> mm/khugepaged.c | 167 ++++++++++++++++++++++++++++++------------------ >> 1 file changed, 104 insertions(+), 63 deletions(-) >> >> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >> index 808523f92c7b..2a897cfb1d03 100644 >> --- a/mm/khugepaged.c >> +++ b/mm/khugepaged.c >> @@ -61,6 +61,12 @@ enum scan_result { >> SCAN_PAGE_FILLED, >> }; >> >> +enum pte_check_result { >> + PTE_CHECK_SUCCEED, >> + PTE_CHECK_CONTINUE, >> + PTE_CHECK_FAIL, >> +}; >> + >> #define CREATE_TRACE_POINTS >> #include >> >> @@ -533,6 +539,87 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte, >> } >> } >> >> +/* >> + * thp_collapse_check_pte - Check if a PTE is suitable for THP collapse >> + * @pte: PTE to check >> + * @vma: VMA the PTE belongs to >> + * @cc: Collapse control settings >> + * @scan_swap_pte: Allow scanning of swap PTEs if true >> + * @none_or_zero: Counter for none/zero PTEs (must be non-NULL) >> + * @unmapped: Counter for swap PTEs (must be non-NULL if scan_swap_pte >> + * is true) >> + * @scan_result: Used to return the failure reason (SCAN_*) on a >> + * PTE_CHECK_FAIL return. Must be non-NULL >> + * >> + * Returns: >> + * PTE_CHECK_SUCCEED - Valid PTE, proceed with collapse >> + * PTE_CHECK_CONTINUE - Skip this none/zero PTE but continue scanning >> + * PTE_CHECK_FAIL - Abort collapse scan >> + */ >> +static inline int thp_collapse_check_pte(pte_t pte, struct vm_area_struct *vma, >> + struct collapse_control *cc, bool scan_swap_pte, >> + int *none_or_zero, int *unmapped, int *scan_result) >> +{ >> + VM_BUG_ON(!none_or_zero || !scan_result); >> + VM_BUG_ON(scan_swap_pte && !unmapped); > > Please use VM_WARN_ONCE_ON and just return. Or put all stats in a struct, > pass and check the struct pointer instead. Yes, will use VM_WARN_ONCE_ON instead of VM_BUG_ON, and just return PTE_CHECK_FAIL. Thanks, Lance > > > Best Regards, > Yan, Zi