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Wang Yaxin 5921629dd6 tools headers UAPI: sync linux/taskstats.h for procacct.c

After commit 9b93f7e327 ("tools/getdelays: use the static UAPI headers
from tools/include/uapi"), the Makefile was changed to use
-I../include/uapi/ instead of -I../../usr/include to ensure tools always
use the up-to-date UAPI headers.

However, only linux/taskstats.h was added to tools/include/uapi/ in commit
e5bbb35a07 ("tools headers UAPI: sync linux/taskstats.h"), but
linux/acct.h was missing.

This causes procacct.c to fail to compile with:

procacct.c:234:37: error: 'AGROUP' undeclared (first use in this function)

gcc -I../include/uapi/    getdelays.c   -o getdelays
gcc -I../include/uapi/    procacct.c   -o procacct
procacct.c: In function `print_procacct':
procacct.c:234:37: error: `AGROUP' undeclared (first use in this function)
did you mean `NOGROUP'?
  234 |  , t->version >= 12 ? (t->ac_flag & AGROUP ? 'P' : 'T') : '?'
      |                                     ^~~~~~
      |                                     NOGROUP
procacct.c:234:37: note: each undeclared ident

because procacct.c uses the AGROUP macro defined in linux/acct.h.

Add the missing linux/acct.h to complete the static UAPI header set.

Link: https://lore.kernel.org/20260527213558929EhiHHy9EDTMjmg3uuDOMi@zte.com.cn
Fixes: 9b93f7e327 ("tools/getdelays: use the static UAPI headers from tools/include/uapi")
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2026-06-03 16:25:50 -07:00

asm

…

asm-generic

tools headers: Update the syscall tables and unistd.h, to support the new 'rseq_slice_yield' syscall

2026-03-05 17:20:23 -03:00

linux

tools headers UAPI: sync linux/taskstats.h for procacct.c

2026-06-03 16:25:50 -07:00

README

…

README

Why we want a copy of kernel headers in tools?
==============================================

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
        [0] = "NORMAL",
        [1] = "RANDOM",
        [2] = "SEQUENTIAL",
        [3] = "WILLNEED",
        [4] = "DONTNEED",
        [5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

Another explanation from Ingo Molnar:
It's better than all the alternatives we tried so far:

 - Symbolic links and direct #includes: this was the original approach but
   was pushed back on from the kernel side, when tooling modified the
   headers and broke them accidentally for kernel builds.

 - Duplicate self-defined ABI headers like glibc: double the maintenance
   burden, double the chance for mistakes, plus there's no tech-driven
   notification mechanism to look at new kernel side changes.

What we are doing now is a third option:

 - A software-enforced copy-on-write mechanism of kernel headers to
   tooling, driven by non-fatal warnings on the tooling side build when
   kernel headers get modified:

    Warning: Kernel ABI header differences:
      diff -u tools/include/uapi/drm/i915_drm.h include/uapi/drm/i915_drm.h
      diff -u tools/include/uapi/linux/fs.h include/uapi/linux/fs.h
      diff -u tools/include/uapi/linux/kvm.h include/uapi/linux/kvm.h
      ...

   The tooling policy is to always pick up the kernel side headers as-is,
   and integate them into the tooling build. The warnings above serve as a
   notification to tooling maintainers that there's changes on the kernel
   side.

We've been using this for many years now, and it might seem hacky, but
works surprisingly well.