From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f72.google.com (mail-pl0-f72.google.com [209.85.160.72]) by kanga.kvack.org (Postfix) with ESMTP id A0D1B6B0009 for ; Tue, 3 Apr 2018 22:57:35 -0400 (EDT) Received: by mail-pl0-f72.google.com with SMTP id x8-v6so12451276pln.9 for ; Tue, 03 Apr 2018 19:57:35 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id b193sor1021880pga.251.2018.04.03.19.57.34 for (Google Transport Security); Tue, 03 Apr 2018 19:57:34 -0700 (PDT) From: Jia He Subject: [PATCH v6 4/5] arm: arm64: introduce pfn_valid_region() Date: Tue, 3 Apr 2018 19:56:18 -0700 Message-Id: <1522810579-7466-5-git-send-email-hejianet@gmail.com> In-Reply-To: <1522810579-7466-1-git-send-email-hejianet@gmail.com> References: <1522810579-7466-1-git-send-email-hejianet@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Russell King , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Andrew Morton , Michal Hocko Cc: Wei Yang , Kees Cook , Laura Abbott , Vladimir Murzin , Philip Derrin , AKASHI Takahiro , James Morse , Steve Capper , Pavel Tatashin , Gioh Kim , Vlastimil Babka , Mel Gorman , Johannes Weiner , Kemi Wang , Petr Tesarik , YASUAKI ISHIMATSU , Andrey Ryabinin , Nikolay Borisov , Daniel Jordan , Daniel Vacek , Eugeniu Rosca , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jia He , Jia He Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") optimized the loop in memmap_init_zone(). But there is still some room for improvement. E.g. in early_pfn_valid(), if pfn and pfn+1 are in the same memblock region, we can record the last returned memblock region index and check pfn++ is still in the same region. Thus we can avoid do the slow binary searches. Currently it only improve the performance on arm/arm64 and will have no impact on other arches. Signed-off-by: Jia He --- include/linux/arm96_common.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/include/linux/arm96_common.h b/include/linux/arm96_common.h index 2f4dea4..bb86bd3 100644 --- a/include/linux/arm96_common.h +++ b/include/linux/arm96_common.h @@ -48,5 +48,29 @@ ulong __init_memblock memblock_next_valid_pfn(ulong pfn) return PHYS_PFN(regions[early_region_idx].base); } EXPORT_SYMBOL(memblock_next_valid_pfn); + +int pfn_valid_region(ulong pfn) +{ + ulong start_pfn, end_pfn; + struct memblock_type *type = &memblock.memory; + struct memblock_region *regions = type->regions; + + if (early_region_idx != -1) { + start_pfn = PFN_DOWN(regions[early_region_idx].base); + end_pfn = PFN_DOWN(regions[early_region_idx].base + + regions[early_region_idx].size); + + if (pfn >= start_pfn && pfn < end_pfn) + return !memblock_is_nomap( + ®ions[early_region_idx]); + } + + early_region_idx = memblock_search_pfn_regions(pfn); + if (early_region_idx == -1) + return false; + + return !memblock_is_nomap(®ions[early_region_idx]); +} +EXPORT_SYMBOL(pfn_valid_region); #endif /*CONFIG_HAVE_ARCH_PFN_VALID*/ #endif /*__ARM96_COMMON_H*/ -- 2.7.4