From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id 233B16B026D for ; Fri, 6 Jul 2018 05:02:54 -0400 (EDT) Received: by mail-pl0-f70.google.com with SMTP id bf1-v6so4188615plb.2 for ; Fri, 06 Jul 2018 02:02:54 -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 a137-v6sor2248548pfa.112.2018.07.06.02.02.53 for (Google Transport Security); Fri, 06 Jul 2018 02:02:53 -0700 (PDT) From: Jia He Subject: [RESEND PATCH v10 6/6] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() Date: Fri, 6 Jul 2018 17:01:15 +0800 Message-Id: <1530867675-9018-7-git-send-email-hejianet@gmail.com> In-Reply-To: <1530867675-9018-1-git-send-email-hejianet@gmail.com> References: <1530867675-9018-1-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 whether pfn++ is still in the same region. Currently it only improve the performance on arm/arm64 and will have no impact on other arches. For the performance improvement, after this set, I can see the time overhead of memmap_init() is reduced from 27956us to 13537us in my armv8a server(QDF2400 with 96G memory, pagesize 64k). Signed-off-by: Jia He --- include/linux/mmzone.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 57cdc42..83b1d11 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1267,11 +1267,16 @@ static inline int pfn_present(unsigned long pfn) #define pfn_to_nid(pfn) (0) #endif -#define early_pfn_valid(pfn) pfn_valid(pfn) #ifdef CONFIG_HAVE_MEMBLOCK_PFN_VALID extern ulong memblock_next_valid_pfn(ulong pfn); #define next_valid_pfn(pfn) memblock_next_valid_pfn(pfn) -#endif + +extern int pfn_valid_region(ulong pfn); +#define early_pfn_valid(pfn) pfn_valid_region(pfn) +#else +#define early_pfn_valid(pfn) pfn_valid(pfn) +#endif /*CONFIG_HAVE_ARCH_PFN_VALID*/ + void sparse_init(void); #else #define sparse_init() do {} while (0) -- 1.8.3.1