From nobody Fri Dec 19 14:36:48 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 690F74B14E for ; Wed, 20 Dec 2023 22:45:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Mys13Qxm" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1703112319; 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=MXqiJu2pun8vKoCf/nv4oO60M9YSAaLT+Ujt3IpxQcI=; b=Mys13QxmQwLAHCKZSp4mAEjX0DjbahtIKGVDoIz4XBp6kp22FvHxV3/kPlecLIOgzDn3KR sQptmYpgMcGfIdbamGwv0276ULWq+i4mEVePY+5jbuyxHoEOcx6kvEvOkFVHTGxyNPfMSZ nYFUFUQ/UeUp4PUxzqBoM7urzL0mApA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-615-YB96pkyOPFqEud271oQ8LQ-1; Wed, 20 Dec 2023 17:45:15 -0500 X-MC-Unique: YB96pkyOPFqEud271oQ8LQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (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 36C35101A551; Wed, 20 Dec 2023 22:45:15 +0000 (UTC) Received: from t14s.fritz.box (unknown [10.39.192.101]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7185940C6EB9; Wed, 20 Dec 2023 22:45:13 +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 v2 03/40] mm/rmap: introduce and use hugetlb_add_file_rmap() Date: Wed, 20 Dec 2023 23:44:27 +0100 Message-ID: <20231220224504.646757-4-david@redhat.com> In-Reply-To: <20231220224504.646757-1-david@redhat.com> References: <20231220224504.646757-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Content-Type: text/plain; charset="utf-8" hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For example, hugetlb currently only supports entire mappings, and treats any mapping as mapped using a single "logical PTE". Let's move it out of the way so we can overhaul our "ordinary" rmap. implementation/interface. Right now we're using page_dup_file_rmap() in some cases where "ordinary" rmap code would have used page_add_file_rmap(). So let's introduce and use hugetlb_add_file_rmap() instead. We won't be adding a "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be doing the same: "dup" is just an optimization for "add". What remains is a single page_dup_file_rmap() call in fork() code. Add sanity checks that we end up with the right folios in the right functions. Reviewed-by: Yin Fengwei Reviewed-by: Ryan Roberts Signed-off-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Muchun Song --- include/linux/rmap.h | 8 ++++++++ mm/hugetlb.c | 6 +++--- mm/migrate.c | 2 +- mm/rmap.c | 1 + 4 files changed, 13 insertions(+), 4 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 64ae6c4d72720..56900a16f41a6 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -211,6 +211,14 @@ void hugetlb_add_anon_rmap(struct folio *, struct vm_a= rea_struct *, void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address); =20 +static inline void hugetlb_add_file_rmap(struct folio *folio) +{ + VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); + VM_WARN_ON_FOLIO(folio_test_anon(folio), folio); + + atomic_inc(&folio->_entire_mapcount); +} + static inline void hugetlb_remove_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ef48ae6738909..57e8981879314 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5408,7 +5408,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, st= ruct mm_struct *src, * sleep during the process. */ if (!folio_test_anon(pte_folio)) { - page_dup_file_rmap(&pte_folio->page, true); + hugetlb_add_file_rmap(pte_folio); } else if (page_try_dup_anon_rmap(&pte_folio->page, true, src_vma)) { pte_t src_pte_old =3D entry; @@ -6279,7 +6279,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *m= m, if (anon_rmap) hugetlb_add_new_anon_rmap(folio, vma, haddr); else - page_dup_file_rmap(&folio->page, true); + hugetlb_add_file_rmap(folio); new_pte =3D make_huge_pte(vma, &folio->page, ((vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_SHARED))); /* @@ -6730,7 +6730,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, goto out_release_unlock; =20 if (folio_in_pagecache) - page_dup_file_rmap(&folio->page, true); + hugetlb_add_file_rmap(folio); else hugetlb_add_new_anon_rmap(folio, dst_vma, dst_addr); =20 diff --git a/mm/migrate.c b/mm/migrate.c index 7d1c3f292d24d..0e912443a18c3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -252,7 +252,7 @@ static bool remove_migration_pte(struct folio *folio, hugetlb_add_anon_rmap(folio, vma, pvmw.address, rmap_flags); else - page_dup_file_rmap(new, true); + hugetlb_add_file_rmap(folio); set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte, psize); } else diff --git a/mm/rmap.c b/mm/rmap.c index 261e1af0d254f..a57ec926daf0c 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1395,6 +1395,7 @@ void folio_add_file_rmap_range(struct folio *folio, s= truct page *page, unsigned int nr_pmdmapped =3D 0, first; int nr =3D 0; =20 + VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); VM_WARN_ON_FOLIO(compound && !folio_test_pmd_mappable(folio), folio); =20 /* Is page being mapped by PTE? Is this its first map to be added? */ --=20 2.43.0