From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f53.google.com (mail-oi0-f53.google.com [209.85.218.53]) by kanga.kvack.org (Postfix) with ESMTP id 60D716B0073 for ; Tue, 3 Mar 2015 12:45:17 -0500 (EST) Received: by oiba3 with SMTP id a3so884519oib.3 for ; Tue, 03 Mar 2015 09:45:17 -0800 (PST) Received: from g1t5425.austin.hp.com (g1t5425.austin.hp.com. [15.216.225.55]) by mx.google.com with ESMTPS id z1si741241obg.51.2015.03.03.09.45.16 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Mar 2015 09:45:16 -0800 (PST) From: Toshi Kani Subject: [PATCH v3 6/6] x86, mm: Support huge KVA mappings on x86 Date: Tue, 3 Mar 2015 10:44:24 -0700 Message-Id: <1425404664-19675-7-git-send-email-toshi.kani@hp.com> In-Reply-To: <1425404664-19675-1-git-send-email-toshi.kani@hp.com> References: <1425404664-19675-1-git-send-email-toshi.kani@hp.com> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, arnd@arndb.de Cc: linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org, dave.hansen@intel.com, Elliott@hp.com, Toshi Kani This patch implements huge KVA mapping interfaces on x86. On x86, MTRRs can override PAT memory types with a 4KB granularity. When using a huge page, MTRRs can override the memory type of the huge page, which may lead a performance penalty. The processor can also behave in an undefined manner if a huge page is mapped to a memory range that MTRRs have mapped with multiple different memory types. Therefore, the mapping code falls back to use a smaller page size toward 4KB when a mapping range is covered by non-WB type of MTRRs. The WB type of MTRRs has no affect on the PAT memory types. pud_set_huge() and pmd_set_huge() call mtrr_type_lookup() to see if a given range is covered by MTRRs. MTRR_TYPE_WRBACK indicates that the range is either covered by WB or not covered and the MTRR default value is set to WB. 0xFF indicates that MTRRs are disabled. HAVE_ARCH_HUGE_VMAP is selected when X86_64 or X86_32 with X86_PAE is set. X86_32 without X86_PAE is not supported since such config can unlikey be benefited from this feature, and there was an issue found in testing. Signed-off-by: Toshi Kani --- arch/x86/Kconfig | 1 + arch/x86/mm/pgtable.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c2fb8a8..ef7d4a6 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -99,6 +99,7 @@ config X86 select IRQ_FORCED_THREADING select HAVE_BPF_JIT if X86_64 select HAVE_ARCH_TRANSPARENT_HUGEPAGE + select HAVE_ARCH_HUGE_VMAP if X86_64 || (X86_32 && X86_PAE) select ARCH_HAS_SG_CHAIN select CLKEVT_I8253 select ARCH_HAVE_NMI_SAFE_CMPXCHG diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 7b22ada..19c897e 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -4,6 +4,7 @@ #include #include #include +#include #define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO @@ -485,3 +486,67 @@ void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys, { __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags)); } + +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP +int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) +{ + u8 mtrr; + + /* + * Do not use a huge page when the range is covered by non-WB type + * of MTRRs. + */ + mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE); + if ((mtrr != MTRR_TYPE_WRBACK) && (mtrr != 0xFF)) + return 0; + + prot = pgprot_4k_2_large(prot); + + set_pte((pte_t *)pud, pfn_pte( + (u64)addr >> PAGE_SHIFT, + __pgprot(pgprot_val(prot) | _PAGE_PSE))); + + return 1; +} + +int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot) +{ + u8 mtrr; + + /* + * Do not use a huge page when the range is covered by non-WB type + * of MTRRs. + */ + mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE); + if ((mtrr != MTRR_TYPE_WRBACK) && (mtrr != 0xFF)) + return 0; + + prot = pgprot_4k_2_large(prot); + + set_pte((pte_t *)pmd, pfn_pte( + (u64)addr >> PAGE_SHIFT, + __pgprot(pgprot_val(prot) | _PAGE_PSE))); + + return 1; +} + +int pud_clear_huge(pud_t *pud) +{ + if (pud_large(*pud)) { + pud_clear(pud); + return 1; + } + + return 0; +} + +int pmd_clear_huge(pmd_t *pmd) +{ + if (pmd_large(*pmd)) { + pmd_clear(pmd); + return 1; + } + + return 0; +} +#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org