From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f176.google.com (mail-we0-f176.google.com [74.125.82.176]) by kanga.kvack.org (Postfix) with ESMTP id AF7846B004D for ; Wed, 25 Jun 2014 11:40:51 -0400 (EDT) Received: by mail-we0-f176.google.com with SMTP id u56so2304355wes.7 for ; Wed, 25 Jun 2014 08:40:51 -0700 (PDT) Received: from mail-wg0-f44.google.com (mail-wg0-f44.google.com [74.125.82.44]) by mx.google.com with ESMTPS id fu4si7464392wib.47.2014.06.25.08.40.42 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Jun 2014 08:40:42 -0700 (PDT) Received: by mail-wg0-f44.google.com with SMTP id x13so2242550wgg.15 for ; Wed, 25 Jun 2014 08:40:42 -0700 (PDT) From: Steve Capper Subject: [PATCH 4/6] arm: mm: Enable RCU fast_gup Date: Wed, 25 Jun 2014 16:40:22 +0100 Message-Id: <1403710824-24340-5-git-send-email-steve.capper@linaro.org> In-Reply-To: <1403710824-24340-1-git-send-email-steve.capper@linaro.org> References: <1403710824-24340-1-git-send-email-steve.capper@linaro.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, linux@arm.linux.org.uk, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: will.deacon@arm.com, gary.robertson@linaro.org, christoffer.dall@linaro.org, peterz@infradead.org, anders.roxell@linaro.org, akpm@linux-foundation.org, Steve Capper Activate the RCU fast_gup for ARM. We also need to force THP splits to broadcast an IPI s.t. we block in the fast_gup page walker. As THP splits are comparatively rare, this should not lead to a noticeable performance degradation. Some pre-requisite functions pud_write and pud_page are also added. Signed-off-by: Steve Capper --- arch/arm/Kconfig | 4 ++++ arch/arm/include/asm/pgtable-3level.h | 8 ++++++++ arch/arm/mm/flush.c | 19 +++++++++++++++++++ 3 files changed, 31 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 888bc8a..6d86ff6 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1712,6 +1712,10 @@ config ARCH_SELECT_MEMORY_MODEL config HAVE_ARCH_PFN_VALID def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM +config HAVE_RCU_GUP + def_bool y + depends on ARM_LPAE + config HIGHMEM bool "High Memory Support" depends on MMU diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index b286ba9..fa8dcb2 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -219,6 +219,8 @@ static inline pte_t pte_mkspecial(pte_t pte) #define __HAVE_ARCH_PMD_WRITE #define pmd_write(pmd) (!(pmd_val(pmd) & PMD_SECT_RDONLY)) +#define pud_write(pud) (0) +#define pud_page(pud) pmd_page(__pmd(pud_val(pud))) #define pmd_hugewillfault(pmd) (!pmd_young(pmd) || !pmd_write(pmd)) #define pmd_thp_or_huge(pmd) (pmd_huge(pmd) || pmd_trans_huge(pmd)) @@ -226,6 +228,12 @@ static inline pte_t pte_mkspecial(pte_t pte) #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define pmd_trans_huge(pmd) (pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT)) #define pmd_trans_splitting(pmd) (pmd_val(pmd) & PMD_SECT_SPLITTING) + +#ifdef CONFIG_HAVE_RCU_TABLE_FREE +#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH +void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmdp); +#endif #endif #define PMD_BIT_FUNC(fn,op) \ diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 43d54f5..9422820 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -400,3 +400,22 @@ void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned l */ __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE); } + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#ifdef CONFIG_HAVE_RCU_TABLE_FREE +static void thp_splitting_flush_sync(void *arg) +{ +} + +void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmdp) +{ + pmd_t pmd = pmd_mksplitting(*pmdp); + VM_BUG_ON(address & ~PMD_MASK); + set_pmd_at(vma->vm_mm, address, pmdp, pmd); + + /* dummy IPI to serialise against fast_gup */ + smp_call_function(thp_splitting_flush_sync, NULL, 1); +} +#endif /* CONFIG_HAVE_RCU_TABLE_FREE */ +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ -- 1.9.3 -- 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