From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1522204606; cv=none; d=google.com; s=arc-20160816; b=yeT+KYHpGGcofGLwwjKUqoWAwJ9Fe8j3c66yfTxHNzGOdvUeypytOPSsMTBzgXUQdo MYFTaXIqZRLiHcBGx/qXItz0sVPE6T8Tl6zDK23xAYPdaDfjDmYiH6NyLIzwd8HQDaob gC8CpfSYUWObrvEsEolsE3iLr849ggXX6nKhX5S7k++CRUnUVpNH6mpSdYwNmWCp2nQW PCghLR+A0GUOuA+yCOahEuALINJMO7Kskq3OIl7m9ibcbSR4HH7cBi2ehfxxz59vM9ZR IH4+KF/u/4tnRt/SOFwn3/eQ3KJ1BBcmXngntCn30C0WNfN7rrnR9JC7FSt3WZe36S8Z BV9g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-transfer-encoding :content-disposition:mime-version:references:reply-to:message-id :subject:cc:to:from:date:dkim-signature:arc-authentication-results; bh=7QdXHmx9F9YIeDyNfeG7yMJ6Ckzmz+MKOQUOV2FFScI=; b=GZzs9Z3whzNLvPGf2eUq73xzs2S6uxgBQ4ZSjYQM/VQQpBtKYaCk02FoZACxpRCtgI MG46v+66CInymuSPi6PcXZJmEmdqxGX1OUEmq3djL1JB+8d5kDig0yfEUtFPHEbHpceL zJZJ8gwV1f0PF1jlhASbypyqLUc7gQpPbVfpZGbKFxcofQpbLu7TvW3xvykSPCooYC50 635H32uAKbk7qWO+zG+9ND7SaB2tLlkrueYEdl7OdnceNRFqtGEeRar/94Z2jWeXIAd2 weTyLsCZYVBrlX+Dc2++p0YgJRrqGiBO17FK8fZ32P8D2ZqJT5TZnkM+neQkCyT7hIGi JNWQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=vYe7Qh25; spf=pass (google.com: domain of richard.weiyang@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=richard.weiyang@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=vYe7Qh25; spf=pass (google.com: domain of richard.weiyang@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=richard.weiyang@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AIpwx4+85Bandgu8V+VTDGCB8MHskwIJibONZSnq8E9md5FYNYNAKDcyBat2XwawQX10FHstXZI/YQ== Date: Wed, 28 Mar 2018 10:36:38 +0800 From: Wei Yang To: Jia He Cc: Wei Yang , 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 , Daniel Vacek , Eugeniu Rosca , Vlastimil Babka , linux-kernel@vger.kernel.org, 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 Subject: Re: [PATCH v3 0/5] optimize memblock_next_valid_pfn and early_pfn_valid Message-ID: <20180328023638.GA94065@WeideMacBook-Pro.local> Reply-To: Wei Yang References: <1522033340-6575-1-git-send-email-hejianet@gmail.com> <20180327010213.GA80447@WeideMacBook-Pro.local> <20180328003012.GA91956@WeideMacBook-Pro.local> <49fefc1c-81dd-98f8-7da5-5b5e85d919e4@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <49fefc1c-81dd-98f8-7da5-5b5e85d919e4@gmail.com> User-Agent: Mutt/1.9.1 (2017-09-22) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1595967659920779416?= X-GMAIL-MSGID: =?utf-8?q?1596147217579124508?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, Mar 28, 2018 at 09:45:33AM +0800, Jia He wrote: > > >On 3/28/2018 8:30 AM, Wei Yang Wrote: >> On Tue, Mar 27, 2018 at 03:15:08PM +0800, Jia He wrote: >> > >> > On 3/27/2018 9:02 AM, Wei Yang Wrote: >> > > On Sun, Mar 25, 2018 at 08:02:14PM -0700, Jia He wrote: >> > > > Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns >> > > > where possible") tried to optimize the loop in memmap_init_zone(). But >> > > > there is still some room for improvement. >> > > > >> > > > Patch 1 remain the memblock_next_valid_pfn when CONFIG_HAVE_ARCH_PFN_VALID >> > > > is enabled >> > > > Patch 2 optimizes the memblock_next_valid_pfn() >> > > > Patch 3~5 optimizes the early_pfn_valid(), I have to split it into parts >> > > > because the changes are located across subsystems. >> > > > >> > > > I tested the pfn loop process in memmap_init(), the same as before. >> > > > As 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). >> > > > >> > > > Attached the memblock region information in my server. >> > > > [ 86.956758] Zone ranges: >> > > > [ 86.959452] DMA [mem 0x0000000000200000-0x00000000ffffffff] >> > > > [ 86.966041] Normal [mem 0x0000000100000000-0x00000017ffffffff] >> > > > [ 86.972631] Movable zone start for each node >> > > > [ 86.977179] Early memory node ranges >> > > > [ 86.980985] node 0: [mem 0x0000000000200000-0x000000000021ffff] >> > > > [ 86.987666] node 0: [mem 0x0000000000820000-0x000000000307ffff] >> > > > [ 86.994348] node 0: [mem 0x0000000003080000-0x000000000308ffff] >> > > > [ 87.001029] node 0: [mem 0x0000000003090000-0x00000000031fffff] >> > > > [ 87.007710] node 0: [mem 0x0000000003200000-0x00000000033fffff] >> > > > [ 87.014392] node 0: [mem 0x0000000003410000-0x000000000563ffff] >> > > > [ 87.021073] node 0: [mem 0x0000000005640000-0x000000000567ffff] >> > > > [ 87.027754] node 0: [mem 0x0000000005680000-0x00000000056dffff] >> > > > [ 87.034435] node 0: [mem 0x00000000056e0000-0x00000000086fffff] >> > > > [ 87.041117] node 0: [mem 0x0000000008700000-0x000000000871ffff] >> > > > [ 87.047798] node 0: [mem 0x0000000008720000-0x000000000894ffff] >> > > > [ 87.054479] node 0: [mem 0x0000000008950000-0x0000000008baffff] >> > > > [ 87.061161] node 0: [mem 0x0000000008bb0000-0x0000000008bcffff] >> > > > [ 87.067842] node 0: [mem 0x0000000008bd0000-0x0000000008c4ffff] >> > > > [ 87.074524] node 0: [mem 0x0000000008c50000-0x0000000008e2ffff] >> > > > [ 87.081205] node 0: [mem 0x0000000008e30000-0x0000000008e4ffff] >> > > > [ 87.087886] node 0: [mem 0x0000000008e50000-0x0000000008fcffff] >> > > > [ 87.094568] node 0: [mem 0x0000000008fd0000-0x000000000910ffff] >> > > > [ 87.101249] node 0: [mem 0x0000000009110000-0x00000000092effff] >> > > > [ 87.107930] node 0: [mem 0x00000000092f0000-0x000000000930ffff] >> > > > [ 87.114612] node 0: [mem 0x0000000009310000-0x000000000963ffff] >> > > > [ 87.121293] node 0: [mem 0x0000000009640000-0x000000000e61ffff] >> > > > [ 87.127975] node 0: [mem 0x000000000e620000-0x000000000e64ffff] >> > > > [ 87.134657] node 0: [mem 0x000000000e650000-0x000000000fffffff] >> > > > [ 87.141338] node 0: [mem 0x0000000010800000-0x0000000017feffff] >> > > > [ 87.148019] node 0: [mem 0x000000001c000000-0x000000001c00ffff] >> > > > [ 87.154701] node 0: [mem 0x000000001c010000-0x000000001c7fffff] >> > > > [ 87.161383] node 0: [mem 0x000000001c810000-0x000000007efbffff] >> > > > [ 87.168064] node 0: [mem 0x000000007efc0000-0x000000007efdffff] >> > > > [ 87.174746] node 0: [mem 0x000000007efe0000-0x000000007efeffff] >> > > > [ 87.181427] node 0: [mem 0x000000007eff0000-0x000000007effffff] >> > > > [ 87.188108] node 0: [mem 0x000000007f000000-0x00000017ffffffff] >> > > Hi, Jia >> > > >> > > I haven't taken a deep look into your code, just one curious question on your >> > > memory layout. >> > > >> > > The log above is printed out in free_area_init_nodes(), which iterates on >> > > memblock.memory and prints them. If I am not wrong, memory regions added to >> > > memblock.memory are ordered and merged if possible. >> > > >> > > While from your log, I see many regions could be merged but are isolated. For >> > > example, the last two region: >> > > >> > > node 0: [mem 0x000000007eff0000-0x000000007effffff] >> > > node 0: [mem 0x000000007f000000-0x00000017ffffffff] >> > > >> > > So I am curious why they are isolated instead of combined to one. >> > > >> > > >From the code, the possible reason is the region's flag differs from each >> > > other. If you have time, would you mind taking a look into this? >> > > >> > Hi Wei >> > I thought these 2 have different flags >> > [    0.000000] idx=30,region [7eff0000:10000]flag=4     <--- aka >> > MEMBLOCK_NOMAP >> > [    0.000000]   node   0: [mem 0x000000007eff0000-0x000000007effffff] >> > [    0.000000] idx=31,region [7f000000:81000000]flag=0 <--- aka MEMBLOCK_NONE >> > [    0.000000]   node   0: [mem 0x000000007f000000-0x00000017ffffffff] >> Thanks. >> >> Hmm, I am not that familiar with those flags, while they look like to indicate >> the physical capability of this range. >> >> MEMBLOCK_NONE no special >> MEMBLOCK_HOTPLUG hotplug-able >> MEMBLOCK_MIRROR high reliable >> MEMBLOCK_NOMAP no direct map >> >> While these flags are not there when they are first added into the memory >> region. When you look at the memblock_add_range(), the last parameter passed >> is always 0. This means current several separated ranges reflect the physical >> memory capability layout. >> >> Then, why this layout is so scattered? As you can see several ranges are less >> than 1M. >> >> If, just my assumption, we could merge some of them, we could have a better >> performance. Less ranges, less searching time. >Thanks for your suggestions, Wei >Need further digging and will consider to improve it in another patchset. > You are welcome :-) I am glad to see your further patchset or investigation, if you are willing me to involve. >-- >Cheers, >Jia -- Wei Yang Help you, Help me