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Tue, 06 Dec 2022 09:48:38 -0500 X-MC-Unique: c9LqIQ1cNnSkTaaD7Ye9vg-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 05DA038164C0; Tue, 6 Dec 2022 14:48:37 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 00479492B04; Tue, 6 Dec 2022 14:48:30 +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 , Guo Ren Subject: [PATCH mm-unstable RFC 05/26] csky/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Date: Tue, 6 Dec 2022 15:47:09 +0100 Message-Id: <20221206144730.163732-6-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221206_064843_465863_D9718B3C X-CRM114-Status: GOOD ( 14.13 ) X-Spam-Score: -0.4 (/) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: 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). We might actually be able to reuse one of the other software bits (_PAGE_READ / PAGE_WRITE) instead, because we only have to keep pte_present(), pte_none() and HW happy. For now, let's keep it simple [...] Content analysis details: (-0.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_MSPIKE_H2 RBL: Average reputation (+2) [170.10.133.124 listed in wl.mailspike.net] -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [170.10.133.124 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.0 SPF_NONE SPF: sender does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.2 DKIMWL_WL_HIGH DKIMwl.org - High trust sender X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.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). We might actually be able to reuse one of the other software bits (_PAGE_READ / PAGE_WRITE) instead, because we only have to keep pte_present(), pte_none() and HW happy. For now, let's keep it simple because there might be something non-obvious. Cc: Guo Ren Signed-off-by: David Hildenbrand --- arch/csky/abiv1/inc/abi/pgtable-bits.h | 13 +++++++++---- arch/csky/abiv2/inc/abi/pgtable-bits.h | 19 ++++++++++++------- arch/csky/include/asm/pgtable.h | 18 ++++++++++++++++++ 3 files changed, 39 insertions(+), 11 deletions(-) diff --git a/arch/csky/abiv1/inc/abi/pgtable-bits.h b/arch/csky/abiv1/inc/abi/pgtable-bits.h index 752c8b3f9194..ae7a2f76dd42 100644 --- a/arch/csky/abiv1/inc/abi/pgtable-bits.h +++ b/arch/csky/abiv1/inc/abi/pgtable-bits.h @@ -10,6 +10,9 @@ #define _PAGE_ACCESSED (1<<3) #define _PAGE_MODIFIED (1<<4) +/* We borrow bit 9 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (1<<9) + /* implemented in hardware */ #define _PAGE_GLOBAL (1<<6) #define _PAGE_VALID (1<<7) @@ -26,7 +29,8 @@ #define _PAGE_PROT_NONE _PAGE_READ /* - * 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) @@ -35,15 +39,16 @@ * bit 6: _PAGE_GLOBAL (zero) * bit 7: _PAGE_VALID (zero) * bit 8: swap type[4] - * bit 9 - 31: swap offset + * bit 9: exclusive marker + * bit 10 - 31: swap offset */ #define __swp_type(x) ((((x).val >> 2) & 0xf) | \ (((x).val >> 4) & 0x10)) -#define __swp_offset(x) ((x).val >> 9) +#define __swp_offset(x) ((x).val >> 10) #define __swp_entry(type, offset) ((swp_entry_t) { \ ((type & 0xf) << 2) | \ ((type & 0x10) << 4) | \ - ((offset) << 9)}) + ((offset) << 10)}) #define HAVE_ARCH_UNMAPPED_AREA diff --git a/arch/csky/abiv2/inc/abi/pgtable-bits.h b/arch/csky/abiv2/inc/abi/pgtable-bits.h index 7e7f389f546f..526152bd2156 100644 --- a/arch/csky/abiv2/inc/abi/pgtable-bits.h +++ b/arch/csky/abiv2/inc/abi/pgtable-bits.h @@ -10,6 +10,9 @@ #define _PAGE_PRESENT (1<<10) #define _PAGE_MODIFIED (1<<11) +/* We borrow bit 7 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (1<<7) + /* implemented in hardware */ #define _PAGE_GLOBAL (1<<0) #define _PAGE_VALID (1<<1) @@ -26,23 +29,25 @@ #define _PAGE_PROT_NONE _PAGE_WRITE /* - * 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_GLOBAL (zero) * bit 1: _PAGE_VALID (zero) * bit 2 - 6: swap type - * bit 7 - 8: swap offset[0 - 1] + * bit 7: exclusive marker + * bit 8: swap offset[0] * bit 9: _PAGE_WRITE (zero) * bit 10: _PAGE_PRESENT (zero) - * bit 11 - 31: swap offset[2 - 22] + * bit 11 - 31: swap offset[1 - 21] */ #define __swp_type(x) (((x).val >> 2) & 0x1f) -#define __swp_offset(x) ((((x).val >> 7) & 0x3) | \ - (((x).val >> 9) & 0x7ffffc)) +#define __swp_offset(x) ((((x).val >> 8) & 0x1) | \ + (((x).val >> 10) & 0x3ffffe)) #define __swp_entry(type, offset) ((swp_entry_t) { \ ((type & 0x1f) << 2) | \ - ((offset & 0x3) << 7) | \ - ((offset & 0x7ffffc) << 9)}) + ((offset & 0x1) << 8) | \ + ((offset & 0x3ffffe) << 10)}) #endif /* __ASM_CSKY_PGTABLE_BITS_H */ diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h index 77bc6caff2d2..574c97b9ecca 100644 --- a/arch/csky/include/asm/pgtable.h +++ b/arch/csky/include/asm/pgtable.h @@ -200,6 +200,24 @@ static inline pte_t pte_mkyoung(pte_t pte) return pte; } +#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; +} + #define __HAVE_PHYS_MEM_ACCESS_PROT struct file; extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,