From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f69.google.com (mail-pl0-f69.google.com [209.85.160.69]) by kanga.kvack.org (Postfix) with ESMTP id 59DDF6B0024 for ; Tue, 27 Mar 2018 22:10:54 -0400 (EDT) Received: by mail-pl0-f69.google.com with SMTP id f3-v6so669809plf.1 for ; Tue, 27 Mar 2018 19:10:54 -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 a33-v6sor1247313pld.51.2018.03.27.19.10.53 for (Google Transport Security); Tue, 27 Mar 2018 19:10:53 -0700 (PDT) Subject: Re: [PATCH v3 5/5] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() References: <1522033340-6575-1-git-send-email-hejianet@gmail.com> <1522033340-6575-6-git-send-email-hejianet@gmail.com> From: Jia He Message-ID: <55b15841-bac7-7576-6da8-edff0fe0e9b2@gmail.com> Date: Wed, 28 Mar 2018 10:10:25 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Daniel Vacek Cc: Andrew Morton , Michal Hocko , Catalin Marinas , Mel Gorman , Will Deacon , Mark Rutland , Ard Biesheuvel , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Pavel Tatashin , Daniel Jordan , AKASHI Takahiro , Gioh Kim , Steven Sistare , Eugeniu Rosca , Vlastimil Babka , open list , linux-mm@kvack.org, James Morse , Steve Capper , x86@kernel.org, Greg Kroah-Hartman , Kate Stewart , Philippe Ombredanne , Johannes Weiner , Kemi Wang , Petr Tesarik , YASUAKI ISHIMATSU , Andrey Ryabinin , Nikolay Borisov , Jia He On 3/28/2018 1:51 AM, Daniel Vacek Wrote: > On Mon, Mar 26, 2018 at 5:02 AM, Jia He wrote: >> 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 check pfn++ is still in the same region. >> >> Currently it only improve the performance on arm64 and will have no >> impact on other arches. >> >> Signed-off-by: Jia He >> --- >> arch/x86/include/asm/mmzone_32.h | 2 +- >> include/linux/mmzone.h | 12 +++++++++--- >> mm/page_alloc.c | 2 +- >> 3 files changed, 11 insertions(+), 5 deletions(-) >> >> diff --git a/arch/x86/include/asm/mmzone_32.h b/arch/x86/include/asm/mmzone_32.h >> index 73d8dd1..329d3ba 100644 >> --- a/arch/x86/include/asm/mmzone_32.h >> +++ b/arch/x86/include/asm/mmzone_32.h >> @@ -49,7 +49,7 @@ static inline int pfn_valid(int pfn) >> return 0; >> } >> >> -#define early_pfn_valid(pfn) pfn_valid((pfn)) >> +#define early_pfn_valid(pfn, last_region_idx) pfn_valid((pfn)) >> >> #endif /* CONFIG_DISCONTIGMEM */ >> >> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h >> index d797716..3a686af 100644 >> --- a/include/linux/mmzone.h >> +++ b/include/linux/mmzone.h >> @@ -1267,9 +1267,15 @@ static inline int pfn_present(unsigned long pfn) >> }) >> #else >> #define pfn_to_nid(pfn) (0) >> -#endif >> +#endif /*CONFIG_NUMA*/ >> + >> +#ifdef CONFIG_HAVE_ARCH_PFN_VALID >> +#define early_pfn_valid(pfn, last_region_idx) \ >> + pfn_valid_region(pfn, last_region_idx) >> +#else >> +#define early_pfn_valid(pfn, last_region_idx) pfn_valid(pfn) >> +#endif /*CONFIG_HAVE_ARCH_PFN_VALID*/ >> >> -#define early_pfn_valid(pfn) pfn_valid(pfn) >> void sparse_init(void); >> #else >> #define sparse_init() do {} while (0) >> @@ -1288,7 +1294,7 @@ struct mminit_pfnnid_cache { >> }; >> >> #ifndef early_pfn_valid >> -#define early_pfn_valid(pfn) (1) >> +#define early_pfn_valid(pfn, last_region_idx) (1) >> #endif >> >> void memory_present(int nid, unsigned long start, unsigned long end); >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 0bb0274..debccf3 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -5484,7 +5484,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, >> if (context != MEMMAP_EARLY) >> goto not_early; >> >> - if (!early_pfn_valid(pfn)) { >> + if (!early_pfn_valid(pfn, &idx)) { >> #if (defined CONFIG_HAVE_MEMBLOCK) && (defined CONFIG_HAVE_ARCH_PFN_VALID) >> /* >> * Skip to the pfn preceding the next valid one (or >> -- >> 2.7.4 >> > Hmm, what about making index global variable instead of changing all > the prototypes? Similar to early_pfnnid_cache for example. Something > like: > > #ifdef CONFIG_HAVE_ARCH_PFN_VALID > extern int early_region_idx __meminitdata; > #define early_pfn_valid(pfn) \ > pfn_valid_region(pfn, &early_region_idx) > #else > #define early_pfn_valid(pfn) pfn_valid(pfn) > #endif /*CONFIG_HAVE_ARCH_PFN_VALID*/ > > And move this to arch/arm64/include/asm/page.h ? > > --nX > Yes. ok with me -- Cheers, Jia