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Adhemerval Zanella 33099d72e4 linux: Simplify get_nprocs
This patch simplifies the memory allocation code and uses the sched
routines instead of reimplement it.  This still uses a stack
allocation buffer, so it can be used on malloc initialization code.

Linux currently supports at maximum of 4096 cpus for most architectures:

$ find -iname Kconfig | xargs git grep -A10 -w NR_CPUS | grep -w range
arch/alpha/Kconfig-	range 2 32
arch/arc/Kconfig-	range 2 4096
arch/arm/Kconfig-	range 2 16 if DEBUG_KMAP_LOCAL
arch/arm/Kconfig-	range 2 32 if !DEBUG_KMAP_LOCAL
arch/arm64/Kconfig-	range 2 4096
arch/csky/Kconfig-	range 2 32
arch/hexagon/Kconfig-	range 2 6 if SMP
arch/ia64/Kconfig-	range 2 4096
arch/mips/Kconfig-	range 2 256
arch/openrisc/Kconfig-	range 2 32
arch/parisc/Kconfig-	range 2 32
arch/riscv/Kconfig-	range 2 32
arch/s390/Kconfig-	range 2 512
arch/sh/Kconfig-	range 2 32
arch/sparc/Kconfig-	range 2 32 if SPARC32
arch/sparc/Kconfig-	range 2 4096 if SPARC64
arch/um/Kconfig-	range 1 1
arch/x86/Kconfig-# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
arch/x86/Kconfig-	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
arch/xtensa/Kconfig-	range 2 32

With x86 supporting 8192:

arch/x86/Kconfig
 976 config NR_CPUS_RANGE_END
 977         int
 978         depends on X86_64
 979         default 8192 if  SMP && CPUMASK_OFFSTACK
 980         default  512 if  SMP && !CPUMASK_OFFSTACK
 981         default    1 if !SMP

So using a maximum of 32k cpu should cover all cases (and I would
expect once we start to have many more CPUs that Linux would provide
a more straightforward way to query for such information).

A test is added to check if sched_getaffinity can successfully return
with large buffers.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-09-27 09:18:12 -03:00
ChangeLog.old
argp Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
assert
benchtests benchtests: Improve reliability of memcmp benchmarks 2021-09-24 18:04:05 -05:00
bits
catgets Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
conform Use $(pie-default) with conformtest 2021-09-17 19:24:14 +00:00
crypt Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
csu Extend struct r_debug to support multiple namespaces [BZ #15971] 2021-09-19 13:51:35 -07:00
ctype
debug Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
dirent Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
dlfcn Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
elf Avoid warning: overriding recipe for .../tst-ro-dynamic-mod.so 2021-09-25 09:06:54 -07:00
gmon Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
gnulib Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
grp Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
gshadow Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
hesiod Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
htl htl: Fix sigset of main thread 2021-09-26 02:40:26 +02:00
hurd Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
iconv iconvconfig: Fix behaviour with --prefix [BZ #28199] 2021-09-13 20:48:35 +05:30
iconvdata Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
include misc: Add __get_nprocs_sched 2021-09-27 09:13:06 -03:00
inet Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
intl Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
io Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
libio Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
locale locale: Add missing second argument to _Static_assert in C-collate-seq.c 2021-09-06 19:43:37 +02:00
localedata Add generic C.UTF-8 locale (Bug 17318) 2021-09-06 11:30:28 -04:00
login Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
mach
malloc misc: Add __get_nprocs_sched 2021-09-27 09:13:06 -03:00
manual Add narrowing fma functions 2021-09-22 21:25:31 +00:00
math Add narrowing fma functions 2021-09-22 21:25:31 +00:00
mathvec
misc misc: Add __get_nprocs_sched 2021-09-27 09:13:06 -03:00
nis Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
nptl nptl: Avoid setxid deadlock with blocked signals in thread exit [BZ #28361] 2021-09-23 09:56:07 +02:00
nptl_db Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
nscd Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
nss Fix failing nss/tst-nss-files-hosts-long with local resolver 2021-09-07 21:41:38 +02:00
po
posix linux: Simplify get_nprocs 2021-09-27 09:18:12 -03:00
pwd Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
resolv Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
resource
rt Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
scripts build-many-glibcs.py: add powerpc64le glibc variant without multiarch 2021-09-24 14:32:35 -05:00
setjmp
shadow Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
signal Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
socket
soft-fp Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
stdio-common vfprintf: Unify argument handling in process_arg 2021-09-23 11:19:20 +02:00
stdlib Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
string Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
sunrpc Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
support xsysconf: Only fail on error results and errno set 2021-09-24 17:30:03 +09:00
sysdeps linux: Simplify get_nprocs 2021-09-27 09:18:12 -03:00
sysvipc Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
termios
time time: Fix compile error in itimer test affecting hurd 2021-09-16 05:21:08 +09:00
timezone Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
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COPYING
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INSTALL
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Makeconfig Run conform/ tests using newly built libc 2021-09-17 13:12:10 +00:00
Makefile testrun.sh: Add support for --tool=rpctrace 2021-09-10 01:24:10 +02:00
Makefile.help
Makefile.in
Makerules
NEWS Define __STDC_IEC_60559_BFP__ and __STDC_IEC_60559_COMPLEX__ 2021-09-24 20:11:56 +00:00
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Rules
SHARED-FILES Mention today's regex merge in SHARED-FILES 2021-09-21 18:00:10 -07:00
abi-tags
aclocal.m4
config.h.in
config.make.in
configure configure: Fix check for INSERT in linker script 2021-09-13 12:39:20 -07:00
configure.ac configure: Fix check for INSERT in linker script 2021-09-13 12:39:20 -07:00
extra-lib.mk
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test-skeleton.c Remove "Contributed by" lines 2021-09-03 22:06:44 +05:30
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