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 0A2AACCD185 for ; Tue, 7 Oct 2025 08:32:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 399A68E000C; Tue, 7 Oct 2025 04:32:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 370EE8E0005; Tue, 7 Oct 2025 04:32:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2ADD48E000C; Tue, 7 Oct 2025 04:32:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 1909B8E0005 for ; Tue, 7 Oct 2025 04:32:21 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 8CCA613BCCE for ; Tue, 7 Oct 2025 08:32:20 +0000 (UTC) X-FDA: 83970651240.13.CF0F4C3 Received: from out-178.mta0.migadu.com (out-178.mta0.migadu.com [91.218.175.178]) by imf19.hostedemail.com (Postfix) with ESMTP id A1E451A000E for ; Tue, 7 Oct 2025 08:32:18 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=poFK5QJq; spf=pass (imf19.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.178 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=1759825939; 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=708hk4v3K6U22ycgyF+Dfx1gxlMvrf8ku8x+RwSAqRg=; b=GhOTfF4UAC3oBDAS2gHbZKMd9as3xqRAs3V8+lC59xUrR1cCqUO+wX58L6oqUQHptLH/Rb vzBv0FgyhL7GKNJgZDeKtZYI/icEnpdiO5GAzbnghFQMKIiLaR0ZbVRAddtfcS9hE6FgeZ tkifcEzyZgRBEtlx25T1C00CuJd/o6Q= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=poFK5QJq; spf=pass (imf19.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.178 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759825939; a=rsa-sha256; cv=none; b=LP7JPNuTiJ0wMfpTeyUlYOh2uPIUhYOQ8h35Sw58WZGYENGU1aXtNTCna8VifYPjS4IvD5 vaT3zo+6UL6cZexGawKsQMmr5YfupQPGWMQehpqJvm7Y1qrKoN9GqA0X8r4VZBw57lQuXR CljEq+TpG3XCVn8Hs0k0LhGgMgEVI7k= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1759825934; 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=708hk4v3K6U22ycgyF+Dfx1gxlMvrf8ku8x+RwSAqRg=; b=poFK5QJqDXcZYwm/pfaHunbTVH62Gwx6FqZESEIDH0vgX6lQXYC8rbj8UPeUdHGaDODAak viQKiHuOefku37kxtGPpa8PnhP8iE+Kns9Tw5w4yDfaA/0yX0DrIOMyBYXpPosVIo31OEn ki2kZeCXxQKJMQWzEEYm4GgIgb8sFXo= Date: Tue, 7 Oct 2025 16:32:07 +0800 MIME-Version: 1.0 Subject: Re: [PATCH mm-new v2 3/3] mm/khugepaged: merge PTE scanning logic into a new helper Content-Language: en-US To: Dev Jain Cc: ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, baohua@kernel.org, ioworker0@gmail.com, richard.weiyang@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, david@redhat.com References: <20251006144338.96519-1-lance.yang@linux.dev> <20251006144338.96519-4-lance.yang@linux.dev> <586f6282-ac7e-42d2-b132-0ba067623ddc@arm.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <586f6282-ac7e-42d2-b132-0ba067623ddc@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: pt7kxycnbhjyfw4ksb39btwagxh8zot3 X-Rspamd-Queue-Id: A1E451A000E X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1759825938-17406 X-HE-Meta: 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 riwOoyDN xPzYJOdbxEQzHlBgD3jaAOIJ6+29SuzAiVbbr1ThUdlQwK9Ll4tsPtKqpay98IQjNt1o9/F6Df5Na9pYa/1bMOWwyxk9Mvxx46dc/cL62HTMaCMei6IL43Gy14Rq0+d8Kvs212Be8zSoVUOQW90RXv2ym02kqhJqdaHmwpgpb/l6W/DlMLwiutcxhwt21XM9B7jiZSfOXBdueAKXoR3T2RuFdQLucoJUn2nbGYeiZMQWNUtFKcY2u0+z8USvMECEHFmP/OvRK68uDr99fZxmUGU/h5LM8O3J6BMASG3BvDa9dFPOMZQap2BD7Mg== 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 2025/10/7 14:28, Dev Jain wrote: > > On 06/10/25 8:13 pm, Lance Yang wrote: >> +static inline int thp_collapse_check_pte(pte_t pte, struct >> vm_area_struct *vma, >> +        unsigned long addr, struct collapse_control *cc, >> +        struct folio **foliop, int *none_or_zero, int *unmapped, >> +        int *shared, int *scan_result) > > Nit: Will prefer the cc parameter to go at the last. Yep, got it. > >> +{ >> +    struct folio *folio = NULL; >> +    struct page *page = NULL; >> + >> +    if (pte_none(pte) || is_zero_pfn(pte_pfn(pte))) { >> +        (*none_or_zero)++; >> +        if (!userfaultfd_armed(vma) && >> +            (!cc->is_khugepaged || >> +             *none_or_zero <= khugepaged_max_ptes_none)) { >> +            return PTE_CHECK_CONTINUE; >> +        } else { >> +            *scan_result = SCAN_EXCEED_NONE_PTE; >> +            count_vm_event(THP_SCAN_EXCEED_NONE_PTE); >> +            return PTE_CHECK_FAIL; >> +        } >> +    } else if (!pte_present(pte)) { >> +        if (!unmapped) { >> +            *scan_result = SCAN_PTE_NON_PRESENT; >> +            return PTE_CHECK_FAIL; >> +        } >> + >> +        if (non_swap_entry(pte_to_swp_entry(pte))) { >> +            *scan_result = SCAN_PTE_NON_PRESENT; >> +            return PTE_CHECK_FAIL; >> +        } >> + >> +        (*unmapped)++; >> +        if (!cc->is_khugepaged || >> +            *unmapped <= khugepaged_max_ptes_swap) { >> +            /* >> +             * Always be strict with uffd-wp enabled swap >> +             * entries. Please see comment below for >> +             * pte_uffd_wp(). >> +             */ >> +            if (pte_swp_uffd_wp(pte)) { >> +                *scan_result = SCAN_PTE_UFFD_WP; >> +                return PTE_CHECK_FAIL; >> +            } >> +            return PTE_CHECK_CONTINUE; >> +        } else { >> +            *scan_result = SCAN_EXCEED_SWAP_PTE; >> +            count_vm_event(THP_SCAN_EXCEED_SWAP_PTE); >> +            return PTE_CHECK_FAIL; >> +        } >> +    } else if (pte_uffd_wp(pte)) { >> +        /* >> +         * Don't collapse the page if any of the small PTEs are >> +         * armed with uffd write protection. Here we can also mark >> +         * the new huge pmd as write protected if any of the small >> +         * ones is marked but that could bring unknown userfault >> +         * messages that falls outside of the registered range. >> +         * So, just be simple. >> +         */ >> +        *scan_result = SCAN_PTE_UFFD_WP; >> +        return PTE_CHECK_FAIL; >> +    } >> + >> +    page = vm_normal_page(vma, addr, pte); > > You should use vm_normal_folio here and drop struct page altogether - > this was also > noted during the review of the mTHP collapse patchset. Right, I missed that vm_normal_folio() was the way to go here :) Thanks for the pointer! Lance