From nobody Mon Dec 29 00:37:19 2025 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 25996C4167B for ; Mon, 4 Dec 2023 14:25:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345548AbjLDOZa (ORCPT ); Mon, 4 Dec 2023 09:25:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235878AbjLDOYp (ORCPT ); Mon, 4 Dec 2023 09:24:45 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA326213D for ; Mon, 4 Dec 2023 06:23:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701699784; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TrXZDuex4z9dO0cUmH/YoAM+lWjEkvkLNiyxPRViLRQ=; b=KDTRyq6BmV95WYbFntuv4EE1f6ZgsMqqardiyo24MUu6hrvmVbTUUhxL8bI4ndh0oQtUuh j5BYr2T+Sux3Hspx8M0foEoZ5UVzJDxVXCT+k7PQUsTX1lKp5jU2lTcCHyr4tvWJYia85a k+/rWFnnp1omkqd1uhznXQSkz1xpAaQ= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-295-Ef5PYdNvM-qrNNOKUuEk5A-1; Mon, 04 Dec 2023 09:23:01 -0500 X-MC-Unique: Ef5PYdNvM-qrNNOKUuEk5A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D721E3813BC8; Mon, 4 Dec 2023 14:23:00 +0000 (UTC) Received: from t14s.fritz.box (unknown [10.39.195.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3BB132026D4C; Mon, 4 Dec 2023 14:22:59 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , "Matthew Wilcox (Oracle)" , Hugh Dickins , Ryan Roberts , Yin Fengwei , Mike Kravetz , Muchun Song , Peter Xu Subject: [PATCH RFC 38/39] mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]() Date: Mon, 4 Dec 2023 15:21:45 +0100 Message-ID: <20231204142146.91437-39-david@redhat.com> In-Reply-To: <20231204142146.91437-1-david@redhat.com> References: <20231204142146.91437-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Let's convert it like we converted all the other rmap functions. Don't introduce folio_try_share_anon_rmap_ptes() for now, as we don't have a user that wants rmap batching in sight. Pretty easy to add later. All users are easy to convert -- only ksm.c doesn't use folios yet but that is left for future work -- so let's just do it in a single shot. While at it, turn the BUG_ON into a WARN_ON_ONCE. Note that page_try_share_anon_rmap() so far didn't care about pte/pmd mappings (no compound parameter). We're changing that so we can perform better sanity checks and make the code actually more readable/consistent. For example, __folio_rmap_sanity_checks() will make sure that a PMD range actually falls completely into the folio. Signed-off-by: David Hildenbrand --- include/linux/rmap.h | 98 ++++++++++++++++++++++++++++++++------------ mm/gup.c | 2 +- mm/huge_memory.c | 9 ++-- mm/internal.h | 4 +- mm/ksm.c | 5 ++- mm/migrate_device.c | 2 +- mm/rmap.c | 9 ++-- 7 files changed, 89 insertions(+), 40 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 3c1df8e020188..ab3ea4583d502 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -267,14 +267,14 @@ static inline int hugetlb_try_dup_anon_rmap(struct fo= lio *folio, return 0; } =20 -/* See page_try_share_anon_rmap() */ +/* See folio_try_share_anon_rmap_*() */ static inline int hugetlb_try_share_anon_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); VM_WARN_ON_FOLIO(!PageAnonExclusive(&folio->page), folio); =20 - /* See page_try_share_anon_rmap() */ + /* See folio_try_share_anon_rmap_*() */ if (IS_ENABLED(CONFIG_HAVE_FAST_GUP)) smp_mb(); =20 @@ -282,7 +282,7 @@ static inline int hugetlb_try_share_anon_rmap(struct fo= lio *folio) return -EBUSY; ClearPageAnonExclusive(&folio->page); =20 - /* See page_try_share_anon_rmap() */ + /* See folio_try_share_anon_rmap_*() */ if (IS_ENABLED(CONFIG_HAVE_FAST_GUP)) smp_mb__after_atomic(); return 0; @@ -463,30 +463,15 @@ static inline int folio_try_dup_anon_rmap_pmd(struct = folio *folio, #endif } =20 -/** - * page_try_share_anon_rmap - try marking an exclusive anonymous page poss= ibly - * shared to prepare for KSM or temporary unmapping - * @page: the exclusive anonymous page to try marking possibly shared - * - * The caller needs to hold the PT lock and has to have the page table ent= ry - * cleared/invalidated. - * - * This is similar to folio_try_dup_anon_rmap_*(), however, not used during - * fork() to duplicate a mapping, but instead to prepare for KSM or tempor= arily - * unmapping a page (swap, migration) via folio_remove_rmap_*(). - * - * Marking the page shared can only fail if the page may be pinned; device - * private pages cannot get pinned and consequently this function cannot f= ail. - * - * Returns 0 if marking the page possibly shared succeeded. Returns -EBUSY - * otherwise. - */ -static inline int page_try_share_anon_rmap(struct page *page) +static inline int __folio_try_share_anon_rmap(struct folio *folio, + struct page *page, unsigned int nr_pages, enum rmap_mode mode) { - VM_BUG_ON_PAGE(!PageAnon(page) || !PageAnonExclusive(page), page); + VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); + VM_WARN_ON_FOLIO(!PageAnonExclusive(page), folio); + __folio_rmap_sanity_checks(folio, page, nr_pages, mode); =20 - /* device private pages cannot get pinned via GUP. */ - if (unlikely(is_device_private_page(page))) { + /* device private folios cannot get pinned via GUP. */ + if (unlikely(folio_is_device_private(folio))) { ClearPageAnonExclusive(page); return 0; } @@ -537,7 +522,7 @@ static inline int page_try_share_anon_rmap(struct page = *page) if (IS_ENABLED(CONFIG_HAVE_FAST_GUP)) smp_mb(); =20 - if (unlikely(page_maybe_dma_pinned(page))) + if (unlikely(folio_maybe_dma_pinned(folio))) return -EBUSY; ClearPageAnonExclusive(page); =20 @@ -550,6 +535,67 @@ static inline int page_try_share_anon_rmap(struct page= *page) return 0; } =20 +/** + * folio_try_share_anon_rmap_pte - try marking an exclusive anonymous page + * mapped by a PTE possibly shared to prepare + * for KSM or temporary unmapping + * @folio: The folio to share a mapping of + * @page: The mapped exclusive page + * + * The caller needs to hold the page table lock and has to have the page t= able + * entries cleared/invalidated. + * + * This is similar to folio_try_dup_anon_rmap_pte(), however, not used dur= ing + * fork() to duplicate mappings, but instead to prepare for KSM or tempora= rily + * unmapping parts of a folio (swap, migration) via folio_remove_rmap_pte(= ). + * + * Marking the mapped page shared can only fail if the folio maybe pinned; + * device private folios cannot get pinned and consequently this function = cannot + * fail. + * + * Returns 0 if marking the mapped page possibly shared succeeded. Returns + * -EBUSY otherwise. + */ +static inline int folio_try_share_anon_rmap_pte(struct folio *folio, + struct page *page) +{ + return __folio_try_share_anon_rmap(folio, page, 1, RMAP_MODE_PTE); +} + +/** + * folio_try_share_anon_rmap_pmd - try marking an exclusive anonymous page + * range mapped by a PMD possibly shared to + * prepare for temporary unmapping + * @folio: The folio to share the mapping of + * @page: The first page to share the mapping of + * + * The page range of the folio is defined by [page, page + HPAGE_PMD_NR) + * + * The caller needs to hold the page table lock and has to have the page t= able + * entries cleared/invalidated. + * + * This is similar to folio_try_dup_anon_rmap_pmd(), however, not used dur= ing + * fork() to duplicate a mapping, but instead to prepare for temporarily + * unmapping parts of a folio (swap, migration) via folio_remove_rmap_pmd(= ). + * + * Marking the mapped pages shared can only fail if the folio maybe pinned; + * device private folios cannot get pinned and consequently this function = cannot + * fail. + * + * Returns 0 if marking the mapped pages possibly shared succeeded. Returns + * -EBUSY otherwise. + */ +static inline int folio_try_share_anon_rmap_pmd(struct folio *folio, + struct page *page) +{ +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + return __folio_try_share_anon_rmap(folio, page, HPAGE_PMD_NR, + RMAP_MODE_PMD); +#else + WARN_ON_ONCE(true); +#endif +} + /* * Called from mm/vmscan.c to handle paging out */ diff --git a/mm/gup.c b/mm/gup.c index 231711efa390d..49f32411c68da 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -177,7 +177,7 @@ struct folio *try_grab_folio(struct page *page, int ref= s, unsigned int flags) /* * Adjust the pincount before re-checking the PTE for changes. * This is essentially a smp_mb() and is paired with a memory - * barrier in page_try_share_anon_rmap(). + * barrier in folio_try_share_anon_rmap_*(). */ smp_mb__after_atomic(); =20 diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 138e1e62790be..ebbf5ee6192e7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2224,10 +2224,11 @@ static void __split_huge_pmd_locked(struct vm_area_= struct *vma, pmd_t *pmd, * In case we cannot clear PageAnonExclusive(), split the PMD * only and let try_to_migrate_one() fail later. * - * See page_try_share_anon_rmap(): invalidate PMD first. + * See folio_try_share_anon_rmap_pmd(): invalidate PMD first. */ anon_exclusive =3D PageAnonExclusive(page); - if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) + if (freeze && anon_exclusive && + folio_try_share_anon_rmap_pmd(folio, page)) freeze =3D false; if (!freeze) { rmap_t rmap_flags =3D RMAP_NONE; @@ -3253,9 +3254,9 @@ int set_pmd_migration_entry(struct page_vma_mapped_wa= lk *pvmw, flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); pmdval =3D pmdp_invalidate(vma, address, pvmw->pmd); =20 - /* See page_try_share_anon_rmap(): invalidate PMD first. */ + /* See folio_try_share_anon_rmap_pmd(): invalidate PMD first. */ anon_exclusive =3D folio_test_anon(folio) && PageAnonExclusive(page); - if (anon_exclusive && page_try_share_anon_rmap(page)) { + if (anon_exclusive && folio_try_share_anon_rmap_pmd(folio, page)) { set_pmd_at(mm, address, pvmw->pmd, pmdval); return -EBUSY; } diff --git a/mm/internal.h b/mm/internal.h index 43dca750c5afc..b9b630717b9b2 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1047,7 +1047,7 @@ enum { * * Ordinary GUP: Using the PT lock * * GUP-fast and fork(): mm->write_protect_seq * * GUP-fast and KSM or temporary unmapping (swap, migration): see - * page_try_share_anon_rmap() + * folio_try_share_anon_rmap_*() * * Must be called with the (sub)page that's actually referenced via the * page table entry, which might not necessarily be the head page for a @@ -1090,7 +1090,7 @@ static inline bool gup_must_unshare(struct vm_area_st= ruct *vma, return is_cow_mapping(vma->vm_flags); } =20 - /* Paired with a memory barrier in page_try_share_anon_rmap(). */ + /* Paired with a memory barrier in folio_try_share_anon_rmap_*(). */ if (IS_ENABLED(CONFIG_HAVE_FAST_GUP)) smp_rmb(); =20 diff --git a/mm/ksm.c b/mm/ksm.c index c23aed4f1a344..51f2d989be2be 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1161,8 +1161,9 @@ static int write_protect_page(struct vm_area_struct *= vma, struct page *page, goto out_unlock; } =20 - /* See page_try_share_anon_rmap(): clear PTE first. */ - if (anon_exclusive && page_try_share_anon_rmap(page)) { + /* See folio_try_share_anon_rmap_pte(): clear PTE first. */ + if (anon_exclusive && + folio_try_share_anon_rmap_pte(page_folio(page), page)) { set_pte_at(mm, pvmw.address, pvmw.pte, entry); goto out_unlock; } diff --git a/mm/migrate_device.c b/mm/migrate_device.c index c51c99151ebb5..9d0c1ad737225 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -202,7 +202,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, if (anon_exclusive) { pte =3D ptep_clear_flush(vma, addr, ptep); =20 - if (page_try_share_anon_rmap(page)) { + if (folio_try_share_anon_rmap_pte(folio, page)) { set_pte_at(mm, addr, ptep, pte); folio_unlock(folio); folio_put(folio); diff --git a/mm/rmap.c b/mm/rmap.c index 8e86024953c03..7bb3a174efc8d 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1817,9 +1817,9 @@ static bool try_to_unmap_one(struct folio *folio, str= uct vm_area_struct *vma, break; } =20 - /* See page_try_share_anon_rmap(): clear PTE first. */ + /* See folio_try_share_anon_rmap(): clear PTE first. */ if (anon_exclusive && - page_try_share_anon_rmap(subpage)) { + folio_try_share_anon_rmap_pte(folio, subpage)) { swap_free(entry); set_pte_at(mm, address, pvmw.pte, pteval); ret =3D false; @@ -2093,7 +2093,8 @@ static bool try_to_migrate_one(struct folio *folio, s= truct vm_area_struct *vma, pte_t swp_pte; =20 if (anon_exclusive) - BUG_ON(page_try_share_anon_rmap(subpage)); + WARN_ON_ONCE(folio_try_share_anon_rmap_pte(folio, + subpage)); =20 /* * Store the pfn of the page in a special migration @@ -2175,7 +2176,7 @@ static bool try_to_migrate_one(struct folio *folio, s= truct vm_area_struct *vma, break; } } else if (anon_exclusive && - page_try_share_anon_rmap(page)) { + folio_try_share_anon_rmap_pte(folio, subpage)) { set_pte_at(mm, address, pvmw.pte, pteval); ret =3D false; page_vma_mapped_walk_done(&pvmw); --=20 2.41.0