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Athira Rajeev 394e4306b0 perf bench numa: Fix the condition checks for max number of NUMA nodes
In systems having higher node numbers available like node
255, perf numa bench will fail with SIGABORT.

  <<>>
  perf: bench/numa.c:1416: init: Assertion `!(g->p.nr_nodes > 64 || g->p.nr_nodes < 0)' failed.
  Aborted (core dumped)
  <<>>

Snippet from 'numactl -H' below on a powerpc system where the highest
node number available is 255:

  available: 6 nodes (0,8,252-255)
  node 0 cpus: <cpu-list>
  node 0 size: 519587 MB
  node 0 free: 516659 MB
  node 8 cpus: <cpu-list>
  node 8 size: 523607 MB
  node 8 free: 486757 MB
  node 252 cpus:
  node 252 size: 0 MB
  node 252 free: 0 MB
  node 253 cpus:
  node 253 size: 0 MB
  node 253 free: 0 MB
  node 254 cpus:
  node 254 size: 0 MB
  node 254 free: 0 MB
  node 255 cpus:
  node 255 size: 0 MB
  node 255 free: 0 MB
  node distances:
  node   0   8  252  253  254  255

Note: <cpu-list> expands to actual cpu list in the original output.
These nodes 252-255 are to represent the memory on GPUs and are valid
nodes.

The perf numa bench init code has a condition check to see if the number
of NUMA nodes (nr_nodes) exceeds MAX_NR_NODES. The value of MAX_NR_NODES
defined in perf code is 64. And the 'nr_nodes' is the value from
numa_max_node() which represents the highest node number available in the
system. In some systems where we could have NUMA node 255, this condition
check fails and results in SIGABORT.

The numa benchmark uses static value of MAX_NR_NODES in the code to
represent size of two NUMA node arrays and node bitmask used for setting
memory policy. Patch adds a fix to dynamically allocate size for the
two arrays and bitmask value based on the node numbers available in the
system. With the fix, perf numa benchmark will work with node configuration
on any system and thus removes the static MAX_NR_NODES value.

Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lore.kernel.org/lkml/1614271802-1503-1-git-send-email-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-03-06 16:54:25 -03:00
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tools perf bench numa: Fix the condition checks for max number of NUMA nodes 2021-03-06 16:54:25 -03:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.