From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
John Hubbard <jhubbard@nvidia.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Yang Shi <shy828301@gmail.com>, Vlastimil Babka <vbabka@suse.cz>,
Nadav Amit <namit@vmware.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Peter Xu <peterx@redhat.com>,
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 <david@redhat.com>,
Brian Cain <bcain@quicinc.com>
Subject: [PATCH mm-unstable RFC 06/26] hexagon/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
Date: Tue, 6 Dec 2022 15:47:10 +0100 [thread overview]
Message-ID: <20221206144730.163732-7-david@redhat.com> (raw)
In-Reply-To: <20221206144730.163732-1-david@redhat.com>
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 <bcain@quicinc.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
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
--
2.38.1
next prev parent reply other threads:[~2022-12-06 14:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-06 14:47 [PATCH mm-unstable RFC 00/26] mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 01/26] mm/debug_vm_pgtable: more pte_swp_exclusive() sanity checks David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 02/26] alpha/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 03/26] arc/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 04/26] arm/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 05/26] csky/mm: " David Hildenbrand
2022-12-06 14:47 ` David Hildenbrand [this message]
2022-12-06 14:47 ` [PATCH mm-unstable RFC 07/26] ia64/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 08/26] loongarch/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 09/26] m68k/mm: remove dummy __swp definitions for nommu David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 10/26] m68k/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 11/26] microblaze/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 12/26] mips/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 13/26] nios2/mm: refactor swap PTE layout David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 14/26] nios2/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 15/26] openrisc/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 16/26] parisc/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 17/26] powerpc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit book3s David Hildenbrand
2022-12-07 13:55 ` Christophe Leroy
2022-12-08 8:52 ` David Hildenbrand
2022-12-08 8:55 ` David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 18/26] powerpc/nohash/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 19/26] riscv/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 20/26] sh/mm: " David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 21/26] sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 22/26] sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 64bit David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 23/26] um/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 24/26] x86/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE also on 32bit David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 25/26] xtensa/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-12-06 14:47 ` [PATCH mm-unstable RFC 26/26] mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-12-14 11:22 ` [PATCH mm-unstable RFC 00/26] mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs David Hildenbrand
2022-12-18 3:32 ` Huacai Chen
2022-12-18 9:59 ` David Hildenbrand
2022-12-19 1:40 ` Huacai Chen
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