<html><body><p><tt><font size="2">"Linuxppc-users" <linuxppc-users-bounces+calvins=us.ibm.com@lists.ozlabs.org> wrote on 09/27/2017 05:45:56 AM:<br><br>> From: Michael Ellerman <mpe@ellerman.id.au></font></tt><br><tt><font size="2">> To: Brian Horton <brianh@linux.vnet.ibm.com>, linuxppc-users@lists.ozlabs.org</font></tt><br><tt><font size="2">> Date: 09/27/2017 05:46 AM</font></tt><br><tt><font size="2">> Subject: Re: [Linuxppc-users] memmap kernel option on ubuntu 16.04 power8</font></tt><br><tt><font size="2">> Sent by: "Linuxppc-users" <linuxppc-users-bounces<br>> +calvins=us.ibm.com@lists.ozlabs.org></font></tt><br><tt><font size="2">> <br>> Hi Brian,<br>> <br>> Brian Horton <brianh@linux.vnet.ibm.com> writes:<br>> > Greetings all.<br>> ><br>> > I'm trying to run some tests with less memory than what's installed. the <br>> > 'mem=128G' option works, but it ends up putting all of the memory on the <br>> > first numa node:<br>> <br>> It doesn't put memory anywhere, it just clamps the total memory, and it<br>> happens that the first (lowest address) 128G of RAM is all on node 0.<br>> <br>> > available: 2 nodes (0,8)<br>> > node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21<br>> > 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40<br>> > 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62<br>> > 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79<br>> > node 0 size: 130695 MB<br>> > node 0 free: 10765 MB<br>> > node 8 cpus: 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97<br>> > 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112<br>> > 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129<br>> > 130 131 132 133 134 135 136 137 138 139 140 141 142 143 1<br>> > 44 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159<br>> > node 8 size: 0 MB<br>> > node 8 free: 0 MB<br>> ><br>> ><br>> > I want 64G on each of the 2 numa nodes. Found this kernel option:<br>> ><br>> > memmap=nn[KMG]$ss[KMG]<br>> > [KNL,ACPI] Mark specific memory as reserved.<br>> > Region of memory to be reserved is from <br>> ss to ss+nn.<br>> > Example: Exclude memory from 0x18690000-0x1869ffff<br>> > memmap=64K$0x18690000<br>> > or<br>> > memmap=0x10000$0x18690000<br>> ><br>> > and it works on x86:<br>> ><br>> > available: 2 nodes (0-1)<br>> > node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 24 25 26 27 28 29 30 31 32 33<br>> > 34 35<br>> > node 0 size: 64315 MB<br>> > node 0 free: 364 MB<br>> > node 1 cpus: 12 13 14 15 16 17 18 19 20 21 22 23 36 37 38 39 40 41<br>> > 42 43 44 45 46 47<br>> > node 1 size: 64507 MB<br>> > node 1 free: 134 MB<br>> ><br>> ><br>> > but i can't get it to work on Ubuntu 16.04 Power8.<br>> <br>> It's not supported on Power.<br>> <br>> Further up in the docs it says:<br>> <br>> memmap=exactmap [KNL,X86] Enable setting of an exact<br>> E820 memory map, as specified by the user.</font></tt><br><br><tt><font size="2">Hi Michael,</font></tt><br><br><br><tt><font size="2">memmap=nn[KMG]@ss[KMG]</font></tt><br><tt><font size="2"> [KNL] Force usage of a specific region of memory.</font></tt><br><tt><font size="2"> Region of memory to be used is from ss to ss+nn.</font></tt><br><br><br><tt><font size="2">It has only [KNL], Does it mean the nn[KMG]@ss[KMG] is supported on Power?</font></tt><br><br><tt><font size="2">Thanks</font></tt><br><tt><font size="2"><br>> <br>> Where the X86 means x86 only.<br>> <br>> > someone said that it worked on RHEL, so maybe it's an Ubuntu-specific bug..<br>> <br>> OK that would be interesting, but I suspect it's not true :)<br>> <br>> > thoughts? ideas?<br>> <br>> AFAIK there's no way to achieve what you're after, without changing<br>> kernel code or creating a custom device tree.<br>> <br>> The mem= option is very primitive, it just clamps the total as I said<br>> above, it's not NUMA aware.<br>> <br>> What hardware/platform are you trying to do this on? Are you familiar<br>> with kexec?<br>> <br>> cheers<br>> _______________________________________________<br>> Linuxppc-users mailing list<br>> Linuxppc-users@lists.ozlabs.org<br>> <a href="https://urldefense.proofpoint.com/v2/url?">https://urldefense.proofpoint.com/v2/url?</a><br>> u=https-3A__lists.ozlabs.org_listinfo_linuxppc-2Dusers&d=DwIGaQ&c=jf_iaSHvJObTbx-<br>> siA1ZOg&r=XEmD5LeSMcW0pq1ccjREOfGKKSZEo6Uip7M_x_R-<br>> NUY&m=__KJPdE4oNc5YucMp3bDQsdoq3pNxf6xKsFapUQGYEc&s=xH6lmOC0jComX4pllM0uCnpa6yZDApj3PNNLt5H8PAU&e=<br>> <br></font></tt><BR>
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