diff options
Diffstat (limited to 'Documentation/x86_64')
| -rw-r--r-- | Documentation/x86_64/boot-options.txt | 14 | ||||
| -rw-r--r-- | Documentation/x86_64/fake-numa-for-cpusets | 66 | ||||
| -rw-r--r-- | Documentation/x86_64/machinecheck | 7 |
3 files changed, 85 insertions, 2 deletions
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index 85f51e5a749f..6177d881983f 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -149,7 +149,19 @@ NUMA numa=noacpi Don't parse the SRAT table for NUMA setup - numa=fake=X Fake X nodes and ignore NUMA setup of the actual machine. + numa=fake=CMDLINE + If a number, fakes CMDLINE nodes and ignores NUMA setup of the + actual machine. Otherwise, system memory is configured + depending on the sizes and coefficients listed. For example: + numa=fake=2*512,1024,4*256,*128 + gives two 512M nodes, a 1024M node, four 256M nodes, and the + rest split into 128M chunks. If the last character of CMDLINE + is a *, the remaining memory is divided up equally among its + coefficient: + numa=fake=2*512,2* + gives two 512M nodes and the rest split into two nodes. + Otherwise, the remaining system RAM is allocated to an + additional node. numa=hotadd=percent Only allow hotadd memory to preallocate page structures upto diff --git a/Documentation/x86_64/fake-numa-for-cpusets b/Documentation/x86_64/fake-numa-for-cpusets new file mode 100644 index 000000000000..d1a985c5b00a --- /dev/null +++ b/Documentation/x86_64/fake-numa-for-cpusets @@ -0,0 +1,66 @@ +Using numa=fake and CPUSets for Resource Management +Written by David Rientjes <rientjes@cs.washington.edu> + +This document describes how the numa=fake x86_64 command-line option can be used +in conjunction with cpusets for coarse memory management. Using this feature, +you can create fake NUMA nodes that represent contiguous chunks of memory and +assign them to cpusets and their attached tasks. This is a way of limiting the +amount of system memory that are available to a certain class of tasks. + +For more information on the features of cpusets, see Documentation/cpusets.txt. +There are a number of different configurations you can use for your needs. For +more information on the numa=fake command line option and its various ways of +configuring fake nodes, see Documentation/x86_64/boot-options.txt. + +For the purposes of this introduction, we'll assume a very primitive NUMA +emulation setup of "numa=fake=4*512,". This will split our system memory into +four equal chunks of 512M each that we can now use to assign to cpusets. As +you become more familiar with using this combination for resource control, +you'll determine a better setup to minimize the number of nodes you have to deal +with. + +A machine may be split as follows with "numa=fake=4*512," as reported by dmesg: + + Faking node 0 at 0000000000000000-0000000020000000 (512MB) + Faking node 1 at 0000000020000000-0000000040000000 (512MB) + Faking node 2 at 0000000040000000-0000000060000000 (512MB) + Faking node 3 at 0000000060000000-0000000080000000 (512MB) + ... + On node 0 totalpages: 130975 + On node 1 totalpages: 131072 + On node 2 totalpages: 131072 + On node 3 totalpages: 131072 + +Now following the instructions for mounting the cpusets filesystem from +Documentation/cpusets.txt, you can assign fake nodes (i.e. contiguous memory +address spaces) to individual cpusets: + + [root@xroads /]# mkdir exampleset + [root@xroads /]# mount -t cpuset none exampleset + [root@xroads /]# mkdir exampleset/ddset + [root@xroads /]# cd exampleset/ddset + [root@xroads /exampleset/ddset]# echo 0-1 > cpus + [root@xroads /exampleset/ddset]# echo 0-1 > mems + +Now this cpuset, 'ddset', will only allowed access to fake nodes 0 and 1 for +memory allocations (1G). + +You can now assign tasks to these cpusets to limit the memory resources +available to them according to the fake nodes assigned as mems: + + [root@xroads /exampleset/ddset]# echo $$ > tasks + [root@xroads /exampleset/ddset]# dd if=/dev/zero of=tmp bs=1024 count=1G + [1] 13425 + +Notice the difference between the system memory usage as reported by +/proc/meminfo between the restricted cpuset case above and the unrestricted +case (i.e. running the same 'dd' command without assigning it to a fake NUMA +cpuset): + Unrestricted Restricted + MemTotal: 3091900 kB 3091900 kB + MemFree: 42113 kB 1513236 kB + +This allows for coarse memory management for the tasks you assign to particular +cpusets. Since cpusets can form a hierarchy, you can create some pretty +interesting combinations of use-cases for various classes of tasks for your +memory management needs. diff --git a/Documentation/x86_64/machinecheck b/Documentation/x86_64/machinecheck index 068a6d9904b9..feaeaf6f6e4d 100644 --- a/Documentation/x86_64/machinecheck +++ b/Documentation/x86_64/machinecheck @@ -36,7 +36,12 @@ between all CPUs. check_interval How often to poll for corrected machine check errors, in seconds - (Note output is hexademical). Default 5 minutes. + (Note output is hexademical). Default 5 minutes. When the poller + finds MCEs it triggers an exponential speedup (poll more often) on + the polling interval. When the poller stops finding MCEs, it + triggers an exponential backoff (poll less often) on the polling + interval. The check_interval variable is both the initial and + maximum polling interval. tolerant Tolerance level. When a machine check exception occurs for a non |