From patchwork Tue Dec 6 14:47:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13065882 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 54099C63704 for ; Tue, 6 Dec 2022 14:51:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234519AbiLFOvU (ORCPT ); Tue, 6 Dec 2022 09:51:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235139AbiLFOvK (ORCPT ); Tue, 6 Dec 2022 09:51:10 -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 E2FE62E6BA for ; Tue, 6 Dec 2022 06:48:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670338128; 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=xnIUuYlJfmQGfvnVf88NtIdpwTWNZSx4XqVJGuJ/Bn4=; b=NTJDAVr6cGhq+bMoTyxlwkzdfns3zW9OgcHkc3ZNOoqdOHC2cLks7/jaCzZXr38g/dsgay KgHt0VwjLcamC3Vx94zbTk5u4dEMQgD5vzUJRwbz2rJDowoFiIvFjI6JXr4iFQVvWra8t4 6J1lue4pFYhtKKs4Htu4BdHdDbiSqXs= 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-381-D8ymNhOSP32dlbMNd3stBw-1; Tue, 06 Dec 2022 09:48:45 -0500 X-MC-Unique: D8ymNhOSP32dlbMNd3stBw-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 95A03101A54E; Tue, 6 Dec 2022 14:48:43 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 87CC2492B04; Tue, 6 Dec 2022 14:48:37 +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 , Brian Cain Subject: [PATCH mm-unstable RFC 06/26] hexagon/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Date: Tue, 6 Dec 2022 15:47:10 +0100 Message-Id: <20221206144730.163732-7-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-sh@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 to 16 GiB (was 32 GiB). While at it, mask the type in __swp_entry(). Cc: Brian Cain Signed-off-by: David Hildenbrand --- arch/hexagon/include/asm/pgtable.h | 37 +++++++++++++++++++++++++----- 1 file changed, 31 insertions(+), 6 deletions(-) diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h index f7048c18b6f9..7eb008e477c8 100644 --- a/arch/hexagon/include/asm/pgtable.h +++ b/arch/hexagon/include/asm/pgtable.h @@ -61,6 +61,9 @@ extern unsigned long empty_zero_page; * So we'll put up with a bit of inefficiency for now... */ +/* We borrow bit 6 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (1<<6) + /* * Top "FOURTH" level (pgd), which for the Hexagon VM is really * only the second from the bottom, pgd and pud both being collapsed. @@ -359,9 +362,12 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) #define ZERO_PAGE(vaddr) (virt_to_page(&empty_zero_page)) /* + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * * Swap/file PTE definitions. If _PAGE_PRESENT is zero, the rest of the PTE is * interpreted as swap information. The remaining free bits are interpreted as - * swap type/offset tuple. Rather than have the TLB fill handler test + * listed below. Rather than have the TLB fill handler test * _PAGE_PRESENT, we're going to reserve the permissions bits and set them to * all zeros for swap entries, which speeds up the miss handler at the cost of * 3 bits of offset. That trade-off can be revisited if necessary, but Hexagon @@ -371,9 +377,10 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) * Format of swap PTE: * bit 0: Present (zero) * bits 1-5: swap type (arch independent layer uses 5 bits max) - * bits 6-9: bits 3:0 of offset + * bit 6: exclusive marker + * bits 7-9: bits 2:0 of offset * bits 10-12: effectively _PAGE_PROTNONE (all zero) - * bits 13-31: bits 22:4 of swap offset + * bits 13-31: bits 21:3 of swap offset * * The split offset makes some of the following macros a little gnarly, * but there's plenty of precedent for this sort of thing. @@ -383,11 +390,29 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) #define __swp_type(swp_pte) (((swp_pte).val >> 1) & 0x1f) #define __swp_offset(swp_pte) \ - ((((swp_pte).val >> 6) & 0xf) | (((swp_pte).val >> 9) & 0x7ffff0)) + ((((swp_pte).val >> 7) & 0x7) | (((swp_pte).val >> 10) & 0x3ffff8)) #define __swp_entry(type, offset) \ ((swp_entry_t) { \ - ((type << 1) | \ - ((offset & 0x7ffff0) << 9) | ((offset & 0xf) << 6)) }) + (((type & 0x1f) << 1) | \ + ((offset & 0x3ffff8) << 10) | ((offset & 0x7) << 7)) }) + +#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) +{ + pte_val(pte) |= _PAGE_SWP_EXCLUSIVE; + return pte; +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE; + return pte; +} #endif