[3/3] Linux: Add missing scheduler constants to <sched.h>

  And add a test, misc/tst-sched-consts, that checks
consistency with <sched.h>.
---
 sysdeps/unix/sysv/linux/Makefile            | 10 ++++
 sysdeps/unix/sysv/linux/bits/sched.h        | 14 ++++++
 sysdeps/unix/sysv/linux/tst-sched-consts.py | 56 +++++++++++++++++++++
 sysdeps/unix/sysv/linux/tst-sched_setattr.c |  2 +
 4 files changed, 82 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/tst-sched-consts.py
  

On 9/5/24 2:33 PM, Florian Weimer wrote:
> And add a test, misc/tst-sched-consts, that checks
> consistency with <sched.h>.

Needs a v2

- Fix parser test description.

> ---
>  sysdeps/unix/sysv/linux/Makefile            | 10 ++++
>  sysdeps/unix/sysv/linux/bits/sched.h        | 14 ++++++
>  sysdeps/unix/sysv/linux/tst-sched-consts.py | 56 +++++++++++++++++++++
>  sysdeps/unix/sysv/linux/tst-sched_setattr.c |  2 +
>  4 files changed, 82 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/tst-sched-consts.py
> 
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 0b45d4e42b..7df51a325c 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -398,6 +398,16 @@ $(objpfx)tst-mount-compile.out: ../sysdeps/unix/sysv/linux/tst-mount-compile.py
>  	  < /dev/null > $@ 2>&1; $(evaluate-test)
>  $(objpfx)tst-mount-compile.out: $(sysdeps-linux-python-deps)
>  
> +tests-special += \
> +  $(objpfx)tst-sched-consts.out \
> +  # tests-special

OK. Adds to tests-special.

> +$(objpfx)tst-sched-consts.out: ../sysdeps/unix/sysv/linux/tst-sched-consts.py
> +	$(sysdeps-linux-python) \
> +	  ../sysdeps/unix/sysv/linux/tst-sched-consts.py \
> +	    $(sysdeps-linux-python-cc) \
> +	  < /dev/null > $@ 2>&1; $(evaluate-test)
> +$(objpfx)tst-sched-consts.out: $(sysdeps-linux-python-deps)

OK.

> +
>  tst-rseq-disable-ENV = GLIBC_TUNABLES=glibc.pthread.rseq=0
>  
>  endif # $(subdir) == misc
> diff --git a/sysdeps/unix/sysv/linux/bits/sched.h b/sysdeps/unix/sysv/linux/bits/sched.h
> index e5b7efb887..a02cb69de7 100644
> --- a/sysdeps/unix/sysv/linux/bits/sched.h
> +++ b/sysdeps/unix/sysv/linux/bits/sched.h
> @@ -29,6 +29,7 @@
>  #define SCHED_FIFO		1
>  #define SCHED_RR		2
>  #ifdef __USE_GNU
> +# define SCHED_NORMAL		SCHED_OTHER

OK. Agreed, we need this.

>  # define SCHED_BATCH		3
>  # define SCHED_ISO		4
>  # define SCHED_IDLE		5
> @@ -37,6 +38,19 @@
>  /* Flags that can be used in policy values.  */
>  # define SCHED_RESET_ON_FORK	0x40000000
>  
> +/* Flags for the sched_flags field in struct sched_attr.   */
> +#define SCHED_FLAG_RESET_ON_FORK	0x01

OK. Definately need this. Matches kernel.

> +#define SCHED_FLAG_RECLAIM		0x02
> +#define SCHED_FLAG_DL_OVERRUN		0x04
> +#define SCHED_FLAG_KEEP_POLICY		0x08
> +#define SCHED_FLAG_KEEP_PARAMS		0x10
> +#define SCHED_FLAG_UTIL_CLAMP_MIN	0x20
> +#define SCHED_FLAG_UTIL_CLAMP_MAX	0x40

OK. Matches kernel.

> +
> +/* Combinations of sched_flags fields.  */
> +#define SCHED_FLAG_KEEP_ALL		0x18

OK.

136 #define SCHED_FLAG_KEEP_ALL     (SCHED_FLAG_KEEP_POLICY | \
137                                  SCHED_FLAG_KEEP_PARAMS)

So 0x08 | 0x10 == 0x18. Agreed.

> +#define SCHED_FLAG_UTIL_CLAMP		0x60

OK.

139 #define SCHED_FLAG_UTIL_CLAMP   (SCHED_FLAG_UTIL_CLAMP_MIN | \
140                                  SCHED_FLAG_UTIL_CLAMP_MAX)

So 0x20 | 0x40 == 0x60. Agreed.

> +
>  /* Use "" to work around incorrect macro expansion of the
>     __has_include argument (GCC PR 80005).  */
>  # ifdef __has_include
> diff --git a/sysdeps/unix/sysv/linux/tst-sched-consts.py b/sysdeps/unix/sysv/linux/tst-sched-consts.py
> new file mode 100644
> index 0000000000..1aa755011c
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-sched-consts.py
> @@ -0,0 +1,56 @@
> +#!/usr/bin/python3
> +# Test that glibc's sched.h constants match the kernel's.
> +# Copyright (C) 2018-2024 Free Software Foundation, Inc.
> +# This file is part of the GNU C Library.
> +#
> +# The GNU C Library is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU Lesser General Public
> +# License as published by the Free Software Foundation; either
> +# version 2.1 of the License, or (at your option) any later version.
> +#
> +# The GNU C Library is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +# Lesser General Public License for more details.
> +#
> +# You should have received a copy of the GNU Lesser General Public
> +# License along with the GNU C Library; if not, see
> +# <https://www.gnu.org/licenses/>.
> +
> +import argparse
> +import sys
> +
> +import glibcextract
> +import glibcsyscalls
> +
> +
> +def main():
> +    """The main entry point."""
> +    parser = argparse.ArgumentParser(
> +        description="Test that glibc's sys/mman.h constants "

Should be sched.h.

> +        "match the kernel's.")
> +    parser.add_argument('--cc', metavar='CC',
> +                        help='C compiler (including options) to use')
> +    args = parser.parse_args()
> +    linux_version_headers = glibcsyscalls.linux_kernel_version(args.cc)
> +    linux_version_glibc = (6, 10)
> +    sys.exit(glibcextract.compare_macro_consts(
> +        '#define _GNU_SOURCE 1\n'
> +        '#include <sched.h>\n',
> +        '#define _GNU_SOURCE 1\n'
> +        '#include <linux/sched.h>\n'
> +        '#include <linux/sched/types.h>\n',
> +        args.cc,
> +        'SCHED_.*',
> +        # SCHED_ISO is reserved, but not implemented in the kernel.
> +        # SCHED_OTHER is the standard name for SCHED_NORMAL.
> +        # SCHED_FLAG_ALL will receive more and more flags, so
> +        # exposing it to userspace does not seem useful.
> +        'SCHED_ISO'
> +        '|SCHED_OTHER'
> +        '|SCHED_FLAG_ALL',
> +        linux_version_glibc > linux_version_headers,
> +        linux_version_headers > linux_version_glibc))
> +
> +if __name__ == '__main__':
> +    main()
> diff --git a/sysdeps/unix/sysv/linux/tst-sched_setattr.c b/sysdeps/unix/sysv/linux/tst-sched_setattr.c
> index 81875b92b0..571050a236 100644
> --- a/sysdeps/unix/sysv/linux/tst-sched_setattr.c
> +++ b/sysdeps/unix/sysv/linux/tst-sched_setattr.c
> @@ -44,6 +44,8 @@ check_unused (void)
>  static int
>  do_test (void)
>  {
> +  _Static_assert (SCHED_OTHER == SCHED_NORMAL,
> +                  "SCHED_OTHER, SCHED_NORMAL values");

OK.

>    TEST_VERIFY (sizeof (struct sched_attr) < sizeof (u));
>  
>    /* Check that reading and re-applying the current policy works.  */