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 4611BF45A1C for ; Tue, 14 Apr 2026 05:47:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6A1806B0088; Tue, 14 Apr 2026 01:47:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 62ACC6B008A; Tue, 14 Apr 2026 01:47:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4F2C46B0092; Tue, 14 Apr 2026 01:47:11 -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 3B1D66B0088 for ; Tue, 14 Apr 2026 01:47:11 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id E15621A01CB for ; Tue, 14 Apr 2026 05:47:10 +0000 (UTC) X-FDA: 84656078220.14.043A106 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf16.hostedemail.com (Postfix) with ESMTP id 104F9180006 for ; Tue, 14 Apr 2026 05:47:08 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=iQBMeGi6; spf=pass (imf16.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=iQBMeGi6; spf=pass (imf16.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776145629; a=rsa-sha256; cv=none; b=alN+iPO2yjLdhCDyI3TaLtycSrYCnsxIqIzNb7wQ+ZKWPA49uWTDfoZ5fm3ud/wkcfr6jL QR/LeSqRCOxc9Z65CFI/Xgei3e+q38/j5LdyusperOUtlA76vow8wYE4X+gJaRqexOmBdy 8MXEHB6AQ/wZn2J3Yh/aCZnh4Rq6QoQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776145629; 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=zmY9ihAtf4ekmMVgXu0dtHQlxfscSPRnYbwyRkb48+U=; b=XLUuKAp4Pf6f6OkYwaohbVkD7GhZW0hvwbwAliMfJPOihNAdnN2vi/QYvLg0k26zioLCmG COyonrUytGxZHU4vDq7SK7Dc9MWcNQjmNkmfQuzKJAB66JCIkpukx549usBbBGU0bafa5S +QIJb8VXHSSeGSA+0xfNEECH+6Eh6L4= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3C8BF4EE4; Mon, 13 Apr 2026 22:47:02 -0700 (PDT) Received: from [10.164.148.48] (MacBook-Pro.blr.arm.com [10.164.148.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 052E03F7B4; Mon, 13 Apr 2026 22:46:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1776145627; bh=W5wCrGEAWO8HkuC+xu/FnjB1AdfwSJhUSgv1NRa0lT4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=iQBMeGi6YLTp229qB+PhAAChcuBCNiAg0FSXJ5oi3l3Jbh7cM9Szog/JUl5Aw/gV/ ANM37lILc0V+iubwGtRf328rlhldqM3Pma5hY2wU6Mbc54BN1XzQohgru0rjn0HCcJ zAyv3x1OBU1F7rr2RGbPG0x6V4Fuh4NXMj5acKII= Message-ID: Date: Tue, 14 Apr 2026 11:16:54 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/9] mm/memory: Batch set uffd-wp markers during zapping To: akpm@linux-foundation.org, david@kernel.org, hughd@google.com, chrisl@kernel.org Cc: ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, riel@surriel.com, harry@kernel.org, jannh@google.com, pfalcato@suse.de, baolin.wang@linux.alibaba.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, youngjun.park@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com References: <20260410103204.120409-1-dev.jain@arm.com> <20260410103204.120409-5-dev.jain@arm.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20260410103204.120409-5-dev.jain@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 104F9180006 X-Stat-Signature: noytncxf7gf5wknu4hshzxk3i9zctoio X-Rspam-User: X-HE-Tag: 1776145628-505955 X-HE-Meta: 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 BhmQ4lpu AeeCdiPUWQmQYS5AwybnbNgGFFo8PxpE3lT0qYfV6BtBYPOaZqycPZ4E/Cpcvg/QKAgpgl0geg1IH0p0/pPRd77R17tX4zFljEOtbsKD1/poVp7ghLJ499i/8A0YNhxpstpEzLaltPikeFmcDH3CKIVtdam33c10T41wOCSIZkv0C6AW8PK54DH+mv9SoJAC8zn8Is0SexLvq00bo91oaAsKbDQcbxYafL5eQTrVv8Ikl0qUg0Y+UOx/3DuK3OCsJuznZ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 10/04/26 4:01 pm, Dev Jain wrote: > In preparation for the next patch, enable batch setting of uffd-wp ptes. > > The code paths passing nr > 1 to zap_install_uffd_wp_if_needed() produce > that nr through either folio_pte_batch or swap_pte_batch, guaranteeing that > all ptes are the same w.r.t belonging to the same type of VMA (anonymous > or non-anonymous, wp-armed or non-wp-armed), and all being marked with > uffd-wp or all being not marked. > > Note that we will have to use set_pte_at() in a loop instead of set_ptes() > since the latter cannot handle present->non-present conversion for > nr_pages > 1. > > Convert documentation of install_uffd_wp_ptes_if_needed to kerneldoc > format. > > No functional change is intended. > > Signed-off-by: Dev Jain > --- > include/linux/mm_inline.h | 32 ++++++++++++++++++++------------ > mm/memory.c | 20 +------------------- > mm/rmap.c | 2 +- > 3 files changed, 22 insertions(+), 32 deletions(-) > > diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h > index a171070e15f05..20c34d14ad539 100644 > --- a/include/linux/mm_inline.h > +++ b/include/linux/mm_inline.h > @@ -566,9 +566,17 @@ static inline pte_marker copy_pte_marker( > return dstm; > } > > -/* > - * If this pte is wr-protected by uffd-wp in any form, arm the special pte to > - * replace a none pte. NOTE! This should only be called when *pte is already > +/** > + * install_uffd_wp_ptes_if_needed - install uffd-wp marker on PTEs that map > + * consecutive pages of the same large folio. > + * @vma: The VMA the pages are mapped into. > + * @addr: Address the first page of this batch is mapped at. > + * @ptep: Page table pointer for the first entry of this batch. > + * @pteval: old value of the entry pointed to by ptep. > + * @nr_ptes: Number of entries to clear (batch size). > + * > + * If the ptes were wr-protected by uffd-wp in any form, arm special ptes to > + * replace none ptes. NOTE! This should only be called when *pte is already > * cleared so we will never accidentally replace something valuable. Meanwhile > * none pte also means we are not demoting the pte so tlb flushed is not needed. > * E.g., when pte cleared the caller should have taken care of the tlb flush. > @@ -576,11 +584,11 @@ static inline pte_marker copy_pte_marker( > * Must be called with pgtable lock held so that no thread will see the none > * pte, and if they see it, they'll fault and serialize at the pgtable lock. > * > - * Returns true if an uffd-wp pte was installed, false otherwise. > + * Returns true if uffd-wp ptes were installed, false otherwise. > */ > static inline bool > -pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr, > - pte_t *pte, pte_t pteval) > +install_uffd_wp_ptes_if_needed(struct vm_area_struct *vma, unsigned long addr, > + pte_t *pte, pte_t pteval, unsigned long nr_ptes) >From Sashiko - kernel doc mismatch. I'll rename pte to ptep. > { > bool arm_uffd_pte = false; > > @@ -610,13 +618,13 @@ pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr, > if (unlikely(pte_swp_uffd_wp_any(pteval))) > arm_uffd_pte = true; > > - if (unlikely(arm_uffd_pte)) { > - set_pte_at(vma->vm_mm, addr, pte, > - make_pte_marker(PTE_MARKER_UFFD_WP)); > - return true; > - } > + if (likely(!arm_uffd_pte)) > + return false; > > - return false; > + for (int i = 0; i < nr_ptes; ++i, ++pte, addr += PAGE_SIZE) > + set_pte_at(vma->vm_mm, addr, pte, make_pte_marker(PTE_MARKER_UFFD_WP)); > + > + return true; > } > > static inline bool vma_has_recency(const struct vm_area_struct *vma) > diff --git a/mm/memory.c b/mm/memory.c > index ea65685711311..eef144fa293d4 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1594,29 +1594,11 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, > unsigned long addr, pte_t *pte, int nr, > struct zap_details *details, pte_t pteval) > { > - bool was_installed = false; > - > - if (!uffd_supports_wp_marker()) > - return false; > - > - /* Zap on anonymous always means dropping everything */ > - if (vma_is_anonymous(vma)) > - return false; > - > if (zap_drop_markers(details)) > return false; > > - for (;;) { > - /* the PFN in the PTE is irrelevant. */ > - if (pte_install_uffd_wp_if_needed(vma, addr, pte, pteval)) > - was_installed = true; > - if (--nr == 0) > - break; > - pte++; > - addr += PAGE_SIZE; > - } > + return install_uffd_wp_ptes_if_needed(vma, addr, pte, pteval, nr); > > - return was_installed; > } > > static __always_inline void zap_present_folio_ptes(struct mmu_gather *tlb, > diff --git a/mm/rmap.c b/mm/rmap.c > index fa5d6599dedf0..20e1fb81c33fc 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -2263,7 +2263,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, > * we may want to replace a none pte with a marker pte if > * it's file-backed, so we don't lose the tracking info. > */ > - pte_install_uffd_wp_if_needed(vma, address, pvmw.pte, pteval); > + install_uffd_wp_ptes_if_needed(vma, address, pvmw.pte, pteval, 1); > > /* Update high watermark before we lower rss */ > update_hiwater_rss(mm);