From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot0-f199.google.com (mail-ot0-f199.google.com [74.125.82.199]) by kanga.kvack.org (Postfix) with ESMTP id C1FFA6B0024 for ; Tue, 27 Mar 2018 13:51:57 -0400 (EDT) Received: by mail-ot0-f199.google.com with SMTP id w43-v6so14203447otd.1 for ; Tue, 27 Mar 2018 10:51:57 -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 m4-v6sor670505otf.145.2018.03.27.10.51.56 for (Google Transport Security); Tue, 27 Mar 2018 10:51:56 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1522033340-6575-6-git-send-email-hejianet@gmail.com> References: <1522033340-6575-1-git-send-email-hejianet@gmail.com> <1522033340-6575-6-git-send-email-hejianet@gmail.com> From: Daniel Vacek Date: Tue, 27 Mar 2018 19:51:56 +0200 Message-ID: Subject: Re: [PATCH v3 5/5] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Jia He 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 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