f58faed7fb
The 'perf bench numa' testcase fails on systems with more than 1K CPUs. Testcase: perf bench numa mem -p 1 -t 3 -P 512 -s 100 -zZ0qcm --thp 1 Snippet of code: <<>> perf: bench/numa.c:302: bind_to_node: Assertion `!(ret)' failed. Aborted (core dumped) <<>> bind_to_node() uses "sched_getaffinity" to save the original cpumask and this call is returning EINVAL ((invalid argument). This happens because the default mask size in glibc is 1024. To overcome this 1024 CPUs mask size limitation of cpu_set_t, change the mask size using the CPU_*_S macros ie, use CPU_ALLOC to allocate cpumask, CPU_ALLOC_SIZE for size. Apart from fixing this for "orig_mask", apply same logic to "mask" as well which is used to setaffinity so that mask size is large enough to represent number of possible CPU's in the system. sched_getaffinity is used in one more place in perf numa bench. It is in "bind_to_cpu" function. Apply the same logic there also. Though currently no failure is reported from there, it is ideal to change getaffinity to work with such system configurations having CPU's more than default mask size supported by glibc. Also fix "sched_setaffinity" to use mask size which is large enough to represent number of possible CPU's in the system. Fixed all places where "bind_cpumask" which is part of "struct thread_data" is used such that bind_cpumask works in all configuration. Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com> Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nageswara R Sastry <rnsastry@linux.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20220412164059.42654-3-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.