From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id 983886B0024 for ; Wed, 11 Apr 2018 03:24:15 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id s6so296268pgn.16 for ; Wed, 11 Apr 2018 00:24:15 -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 g9sor98095pgo.145.2018.04.11.00.24.14 for (Google Transport Security); Wed, 11 Apr 2018 00:24:14 -0700 (PDT) From: Jia He Subject: [PATCH v8 6/6] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() Date: Wed, 11 Apr 2018 00:21:57 -0700 Message-Id: <1523431317-30612-7-git-send-email-hejianet@gmail.com> In-Reply-To: <1523431317-30612-1-git-send-email-hejianet@gmail.com> References: <1523431317-30612-1-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 41313 us to 24345 us in my armv8a server(QDF2400 with 96G memory). 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 c40297d..426db40 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1271,11 +1271,16 @@ 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) -- 2.7.4