From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp07.in.ibm.com (e28smtp07.in.ibm.com [122.248.162.7]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id BFBD014017A for ; Thu, 8 May 2014 19:28:52 +1000 (EST) Received: from /spool/local by e28smtp07.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 8 May 2014 14:58:47 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 01711E0057 for ; Thu, 8 May 2014 14:59:11 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s489SUe917039502 for ; Thu, 8 May 2014 14:58:31 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s489SJ3s027904 for ; Thu, 8 May 2014 14:58:22 +0530 From: Madhavan Srinivasan To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org Subject: [PATCH V4 1/2] mm: move FAULT_AROUND_ORDER to arch/ Date: Thu, 8 May 2014 14:58:15 +0530 Message-Id: <1399541296-18810-2-git-send-email-maddy@linux.vnet.ibm.com> In-Reply-To: <1399541296-18810-1-git-send-email-maddy@linux.vnet.ibm.com> References: <1399541296-18810-1-git-send-email-maddy@linux.vnet.ibm.com> Cc: riel@redhat.com, ak@linux.intel.com, peterz@infradead.org, rusty@rustcorp.com.au, dave.hansen@intel.com, Madhavan Srinivasan , paulus@samba.org, mgorman@suse.de, akpm@linux-foundation.org, mingo@kernel.org, kirill.shutemov@linux.intel.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Kirill A. Shutemov with 8c6e50b029 commit introduced vm_ops->map_pages() for mapping easy accessible pages around fault address in hope to reduce number of minor page faults. This patch creates infrastructure to modify the FAULT_AROUND_ORDER value using mm/Kconfig. This will enable architecture maintainers to decide on suitable FAULT_AROUND_ORDER value based on performance data for that architecture. Patch also defaults FAULT_AROUND_ORDER Kconfig element to 4. Signed-off-by: Madhavan Srinivasan --- mm/Kconfig | 8 ++++++++ mm/memory.c | 25 ++++++------------------- 2 files changed, 14 insertions(+), 19 deletions(-) diff --git a/mm/Kconfig b/mm/Kconfig index ebe5880..c7fc4f1 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -176,6 +176,14 @@ config MOVABLE_NODE config HAVE_BOOTMEM_INFO_NODE def_bool n +# +# Fault around order is a control knob to decide the fault around pages. +# Default value is set to 4 , but the arch can override it as desired. +# +config FAULT_AROUND_ORDER + int + default 4 + # eventually, we can have this option just 'select SPARSEMEM' config MEMORY_HOTPLUG bool "Allow for memory hot-add" diff --git a/mm/memory.c b/mm/memory.c index 037b812..e3931ef 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3402,11 +3402,9 @@ void do_set_pte(struct vm_area_struct *vma, unsigned long address, update_mmu_cache(vma, address, pte); } -#define FAULT_AROUND_ORDER 4 +unsigned int fault_around_order __read_mostly = CONFIG_FAULT_AROUND_ORDER; #ifdef CONFIG_DEBUG_FS -static unsigned int fault_around_order = FAULT_AROUND_ORDER; - static int fault_around_order_get(void *data, u64 *val) { *val = fault_around_order; @@ -3415,7 +3413,6 @@ static int fault_around_order_get(void *data, u64 *val) static int fault_around_order_set(void *data, u64 val) { - BUILD_BUG_ON((1UL << FAULT_AROUND_ORDER) > PTRS_PER_PTE); if (1UL << val > PTRS_PER_PTE) return -EINVAL; fault_around_order = val; @@ -3435,31 +3432,21 @@ static int __init fault_around_debugfs(void) return 0; } late_initcall(fault_around_debugfs); +#endif static inline unsigned long fault_around_pages(void) { - return 1UL << fault_around_order; -} - -static inline unsigned long fault_around_mask(void) -{ - return ~((1UL << (PAGE_SHIFT + fault_around_order)) - 1); -} -#else -static inline unsigned long fault_around_pages(void) -{ unsigned long nr_pages; - nr_pages = 1UL << FAULT_AROUND_ORDER; - BUILD_BUG_ON(nr_pages > PTRS_PER_PTE); + nr_pages = 1UL << fault_around_order; + VM_BUG_ON(nr_pages > PTRS_PER_PTE); return nr_pages; } static inline unsigned long fault_around_mask(void) { - return ~((1UL << (PAGE_SHIFT + FAULT_AROUND_ORDER)) - 1); + return ~((1UL << (PAGE_SHIFT + fault_around_order)) - 1); } -#endif static void do_fault_around(struct vm_area_struct *vma, unsigned long address, pte_t *pte, pgoff_t pgoff, unsigned int flags) @@ -3515,7 +3502,7 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma, * if page by the offset is not ready to be mapped (cold cache or * something). */ - if (vma->vm_ops->map_pages) { + if ((vma->vm_ops->map_pages) && fault_around_order) { pte = pte_offset_map_lock(mm, pmd, address, &ptl); do_fault_around(vma, address, pte, pgoff, flags); if (!pte_same(*pte, orig_pte)) -- 1.7.10.4