From patchwork Tue Dec 6 14:47:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13065969 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 00BF0C4708E for ; Tue, 6 Dec 2022 14:56:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231530AbiLFO4Q (ORCPT ); Tue, 6 Dec 2022 09:56:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234083AbiLFOzu (ORCPT ); Tue, 6 Dec 2022 09:55:50 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E7CC2F67B for ; Tue, 6 Dec 2022 06:50:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670338212; 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=YKMiOBgP33pVu/vubLTpfqqseR2sVQaL/Lh8pj/G0b4=; b=UiRHHq0cgXP06KpnNM63turFZgU3og5dO6BAFn2tId7RVFSLIMWmiFYN1DlEB/owdPAlIA RdCfIYa8TBvxefxzR8uRTWzY0GWWRqwozQAyyUKk0Doh648CgJC+yssC1vnSBsBIYe+yUr z2w2miWSLuu/CpX/Q/ZHGYBDfU2tDos= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-604-McWRY_tDNGK-2jFIwaXqLA-1; Tue, 06 Dec 2022 09:50:08 -0500 X-MC-Unique: McWRY_tDNGK-2jFIwaXqLA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EA86385A59D; Tue, 6 Dec 2022 14:50:06 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8157A492B04; Tue, 6 Dec 2022 14:50:00 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Hugh Dickins , John Hubbard , Jason Gunthorpe , Mike Rapoport , Yang Shi , Vlastimil Babka , Nadav Amit , Andrea Arcangeli , Peter Xu , linux-mm@kvack.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, David Hildenbrand , Paul Walmsley , Palmer Dabbelt , Albert Ou Subject: [PATCH mm-unstable RFC 19/26] riscv/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Date: Tue, 6 Dec 2022 15:47:23 +0100 Message-Id: <20221206144730.163732-20-david@redhat.com> In-Reply-To: <20221206144730.163732-1-david@redhat.com> References: <20221206144730.163732-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the offset. This reduces the maximum swap space per file: on 32bit to 16 GiB (was 32 GiB). Note that this bit does not conflict with swap PMDs and could also be used in swap PMD context later. While at it, mask the type in __swp_entry(). Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Signed-off-by: David Hildenbrand --- arch/riscv/include/asm/pgtable-bits.h | 3 +++ arch/riscv/include/asm/pgtable.h | 29 ++++++++++++++++++++++----- 2 files changed, 27 insertions(+), 5 deletions(-) diff --git a/arch/riscv/include/asm/pgtable-bits.h b/arch/riscv/include/asm/pgtable-bits.h index b9e13a8fe2b7..f896708e8331 100644 --- a/arch/riscv/include/asm/pgtable-bits.h +++ b/arch/riscv/include/asm/pgtable-bits.h @@ -27,6 +27,9 @@ */ #define _PAGE_PROT_NONE _PAGE_GLOBAL +/* Used for swap PTEs only. */ +#define _PAGE_SWP_EXCLUSIVE _PAGE_ACCESSED + #define _PAGE_PFN_SHIFT 10 /* diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 7ee3ac315c7c..9730f9fed197 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -721,16 +721,18 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ /* - * Encode and decode a swap entry + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). * * Format of swap PTE: * bit 0: _PAGE_PRESENT (zero) * bit 1 to 3: _PAGE_LEAF (zero) * bit 5: _PAGE_PROT_NONE (zero) - * bits 6 to 10: swap type - * bits 10 to XLEN-1: swap offset + * bit 6: exclusive marker + * bits 7 to 11: swap type + * bits 11 to XLEN-1: swap offset */ -#define __SWP_TYPE_SHIFT 6 +#define __SWP_TYPE_SHIFT 7 #define __SWP_TYPE_BITS 5 #define __SWP_TYPE_MASK ((1UL << __SWP_TYPE_BITS) - 1) #define __SWP_OFFSET_SHIFT (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT) @@ -741,11 +743,28 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, #define __swp_type(x) (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK) #define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT) #define __swp_entry(type, offset) ((swp_entry_t) \ - { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) }) + { (((type) & __SWP_TYPE_MASK) << __SWP_TYPE_SHIFT) | \ + ((offset) << __SWP_OFFSET_SHIFT) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) +#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE +static inline int pte_swp_exclusive(pte_t pte) +{ + return pte_val(pte) & _PAGE_SWP_EXCLUSIVE; +} + +static inline pte_t pte_swp_mkexclusive(pte_t pte) +{ + return __pte(pte_val(pte) | _PAGE_SWP_EXCLUSIVE); +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + return __pte(pte_val(pte) & ~_PAGE_SWP_EXCLUSIVE); +} + #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val(pmd) }) #define __swp_entry_to_pmd(swp) __pmd((swp).val)