From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1522202971; cv=none; d=google.com; s=arc-20160816; b=0vhLY+tmoFAWqHucjMDZfWJQT2tkjmtZ5EgAC1BOuDyNipIqQGNahu9lZ4ao2kHcg8 Zvm4XPZFc0oTsHRi5ltB3g4S+WHuDVCL93ToDMETncrpKT0K5SGiXxdBc3s4rfCW506i zwYY1wP5TUZ12r2n63drE1ILiKuuhEEXUp3Z8sVBv3orwlcwO5iNwsoBam5aU815LGqE NgxBh3RDWarK9yRbeiZ3n3QaDnTttPbPP76c3igIrjpMa0IdNoMIQoEpM6dOIEDDAGVa tNXRrHTDv4Oib795sk/9PhLJeCTDarhpM9MdKz/y+axBrhYCWVUOWwBRlZEim4KDcsJ4 wyJQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:in-reply-to:mime-version:user-agent:date :message-id:from:references:cc:to:subject:dkim-signature :arc-authentication-results; bh=DyGyONIO3XJYPV8cl4bV1jHOzIE1A9VYVJHfgKYukU4=; b=XoWwudCBpHa5YrFg9EC7LadsrE3+qF/sJ/jkMesOaM9/T4WS6d3QrupiY3KfukPoLV ZhQW9ReUHWRUArrDmXAsxX4kj/W8vQeHZ2K6SJGGYXUQ4vVocSyBb0rNty0L3hp1f+Dw 0siL6C0ux5THUlP1sOTl8sKDCnc4CABsBZ4QrvgLIFB5CPlETcc5pNxlpbrsrHdq58+W s8oe4oImqf6MNtZV5jjRNNFqbzwSkDJke0SzW0CAuXE1pRUuRAXTwVftpgyQ+rVhyJlo r/9TSwYbnX83foeL/xWjF6Y6+Ve5tRfpN0ZL5Vsub7FZRd610VoiGWiMMys+0AlGwFFI JSUg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=Rq8nKQoI; spf=pass (google.com: domain of hejianet@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=hejianet@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=Rq8nKQoI; spf=pass (google.com: domain of hejianet@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=hejianet@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AIpwx49NQNjA4WuftJsOjxJ0pTPq2qBJ8zKwG2mf2wOb8nNDvvmSdIKj/QcqLotOWK2sRM2IMo5hhQ== Subject: Re: [PATCH v3 2/5] mm: page_alloc: reduce unnecessary binary search in memblock_next_valid_pfn() 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 References: <1522033340-6575-1-git-send-email-hejianet@gmail.com> <1522033340-6575-3-git-send-email-hejianet@gmail.com> From: Jia He Message-ID: Date: Wed, 28 Mar 2018 10:09:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1595967686923865256?= X-GMAIL-MSGID: =?utf-8?q?1596145503025443896?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 3/28/2018 1:17 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. if pfn and pfn+1 are in the same >> memblock region, we can simply pfn++ instead of doing the binary search >> in memblock_next_valid_pfn. This patch only works when >> CONFIG_HAVE_ARCH_PFN_VALID is enable. >> >> Signed-off-by: Jia He >> --- >> include/linux/memblock.h | 2 +- >> mm/memblock.c | 73 +++++++++++++++++++++++++++++------------------- >> mm/page_alloc.c | 3 +- >> 3 files changed, 47 insertions(+), 31 deletions(-) >> >> diff --git a/include/linux/memblock.h b/include/linux/memblock.h >> index efbbe4b..a8fb2ab 100644 >> --- a/include/linux/memblock.h >> +++ b/include/linux/memblock.h >> @@ -204,7 +204,7 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, >> #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ >> >> #ifdef CONFIG_HAVE_ARCH_PFN_VALID >> -unsigned long memblock_next_valid_pfn(unsigned long pfn); >> +unsigned long memblock_next_valid_pfn(unsigned long pfn, int *idx); >> #endif >> >> /** >> diff --git a/mm/memblock.c b/mm/memblock.c >> index bea5a9c..06c1a08 100644 >> --- a/mm/memblock.c >> +++ b/mm/memblock.c >> @@ -1102,35 +1102,6 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid, >> *out_nid = r->nid; >> } >> >> -#ifdef CONFIG_HAVE_ARCH_PFN_VALID >> -unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn) >> -{ >> - struct memblock_type *type = &memblock.memory; >> - unsigned int right = type->cnt; >> - unsigned int mid, left = 0; >> - phys_addr_t addr = PFN_PHYS(++pfn); >> - >> - do { >> - mid = (right + left) / 2; >> - >> - if (addr < type->regions[mid].base) >> - right = mid; >> - else if (addr >= (type->regions[mid].base + >> - type->regions[mid].size)) >> - left = mid + 1; >> - else { >> - /* addr is within the region, so pfn is valid */ >> - return pfn; >> - } >> - } while (left < right); >> - >> - if (right == type->cnt) >> - return -1UL; >> - else >> - return PHYS_PFN(type->regions[right].base); >> -} >> -#endif /*CONFIG_HAVE_ARCH_PFN_VALID*/ >> - >> /** >> * memblock_set_node - set node ID on memblock regions >> * @base: base of area to set node ID for >> @@ -1162,6 +1133,50 @@ int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size, >> } >> #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ >> >> +#ifdef CONFIG_HAVE_ARCH_PFN_VALID >> +unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn, >> + int *last_idx) >> +{ >> + struct memblock_type *type = &memblock.memory; >> + unsigned int right = type->cnt; >> + unsigned int mid, left = 0; >> + unsigned long start_pfn, end_pfn; >> + phys_addr_t addr = PFN_PHYS(++pfn); >> + >> + /* fast path, return pfh+1 if next pfn is in the same region */ >> + if (*last_idx != -1) { >> + start_pfn = PFN_DOWN(type->regions[*last_idx].base); >> + end_pfn = PFN_DOWN(type->regions[*last_idx].base + >> + type->regions[*last_idx].size); >> + >> + if (pfn < end_pfn && pfn > start_pfn) >> + return pfn; >> + } >> + >> + /* slow path, do the binary searching */ >> + do { >> + mid = (right + left) / 2; >> + >> + if (addr < type->regions[mid].base) >> + right = mid; >> + else if (addr >= (type->regions[mid].base + >> + type->regions[mid].size)) >> + left = mid + 1; >> + else { >> + *last_idx = mid; >> + return pfn; >> + } >> + } while (left < right); >> + >> + if (right == type->cnt) >> + return -1UL; >> + >> + *last_idx = right; >> + >> + return PHYS_PFN(type->regions[*last_idx].base); >> +} >> +#endif /*CONFIG_HAVE_ARCH_PFN_VALID*/ >> + >> static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size, >> phys_addr_t align, phys_addr_t start, >> phys_addr_t end, int nid, ulong flags) >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 2a967f7..0bb0274 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -5459,6 +5459,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, >> unsigned long end_pfn = start_pfn + size; >> pg_data_t *pgdat = NODE_DATA(nid); >> unsigned long pfn; >> + int idx = -1; >> unsigned long nr_initialised = 0; >> struct page *page; >> #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP >> @@ -5490,7 +5491,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, >> * end_pfn), such that we hit a valid pfn (or end_pfn) >> * on our next iteration of the loop. >> */ >> - pfn = memblock_next_valid_pfn(pfn) - 1; >> + pfn = memblock_next_valid_pfn(pfn, &idx) - 1; >> #endif >> continue; >> } >> -- >> 2.7.4 >> > So the function is only defined with CONFIG_HAVE_ARCH_PFN_VALID but > it's called with CONFIG_HAVE_MEMBLOCK_NODE_MAP? The definition should > likely depend on both options as the function really depends on both > conditions. Otherwise it should be defined nop. > > --nX > Yes, thanks -- Cheers, Jia