A mirror of the official Linux kernel repository just in case
Go to file
Arnaldo Carvalho de Melo 3d1d57debe tools build: Remove needless libpython-version feature check that breaks test-all fast path
Since 66dfdff03d ("perf tools: Add Python 3 support") we don't use
the tools/build/feature/test-libpython-version.c version in any Makefile
feature check:

  $ find tools/ -type f | xargs grep feature-libpython-version
  $

The only place where this was used was removed in 66dfdff03d:

  -        ifneq ($(feature-libpython-version), 1)
  -          $(warning Python 3 is not yet supported; please set)
  -          $(warning PYTHON and/or PYTHON_CONFIG appropriately.)
  -          $(warning If you also have Python 2 installed, then)
  -          $(warning try something like:)
  -          $(warning $(and ,))
  -          $(warning $(and ,)  make PYTHON=python2)
  -          $(warning $(and ,))
  -          $(warning Otherwise, disable Python support entirely:)
  -          $(warning $(and ,))
  -          $(warning $(and ,)  make NO_LIBPYTHON=1)
  -          $(warning $(and ,))
  -          $(error   $(and ,))
  -        else
  -          LDFLAGS += $(PYTHON_EMBED_LDFLAGS)
  -          EXTLIBS += $(PYTHON_EMBED_LIBADD)
  -          LANG_BINDINGS += $(obj-perf)python/perf.so
  -          $(call detected,CONFIG_LIBPYTHON)
  -        endif

And nowadays we either build with PYTHON=python3 or just install the
python3 devel packages and perf will build against it.

But the leftover feature-libpython-version check made the fast path
feature detection to break in all cases except when python2 devel files
were installed:

  $ rpm -qa | grep python.*devel
  python3-devel-3.9.7-1.fc34.x86_64
  $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf ;
  $ make -C tools/perf O=/tmp/build/perf install-bin
  make: Entering directory '/var/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j32' parallel build
    HOSTCC  /tmp/build/perf/fixdep.o
  <SNIP>
  $ cat /tmp/build/perf/feature/test-all.make.output
  In file included from test-all.c:18:
  test-libpython-version.c:5:10: error: #error
      5 |         #error
        |          ^~~~~
  $ ldd ~/bin/perf | grep python
	libpython3.9.so.1.0 => /lib64/libpython3.9.so.1.0 (0x00007fda6dbcf000)
  $

As python3 is the norm these days, fix this by just removing the unused
feature-libpython-version feature check, making the test-all fast path
to work with the common case.

With this:

  $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf ;
  $ make -C tools/perf O=/tmp/build/perf install-bin |& head
  make: Entering directory '/var/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j32' parallel build
    HOSTCC  /tmp/build/perf/fixdep.o
    HOSTLD  /tmp/build/perf/fixdep-in.o
    LINK    /tmp/build/perf/fixdep

  Auto-detecting system features:
  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  $ ldd ~/bin/perf | grep python
	libpython3.9.so.1.0 => /lib64/libpython3.9.so.1.0 (0x00007f58800b0000)
  $ cat /tmp/build/perf/feature/test-all.make.output
  $

Reviewed-by: James Clark <james.clark@arm.com>
Fixes: 66dfdff03d ("perf tools: Add Python 3 support")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jaroslav Škarvada <jskarvad@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/YaYmeeC6CS2b8OSz@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-12-06 21:57:53 -03:00
arch EFI fix for v5.16 2021-12-06 10:09:00 -08:00
block block: call rq_qos_done() before ref check in batch completions 2021-11-26 09:53:23 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Update to zstd-1.4.10 2021-11-13 15:32:30 -08:00
Documentation A few important documentation fixes, including breakage that comes with 2021-12-06 10:46:20 -08:00
drivers parisc architecture bug and warning fixes for kernel v5.16-rc4 2021-12-05 12:58:18 -08:00
fs Fixes for 5.16-rc3: 2021-12-04 17:22:53 -08:00
include regulator: Documentation fix for v5.16 2021-12-06 10:14:12 -08:00
init kbuild: Fix -Wimplicit-fallthrough=5 error for GCC 5.x and 6.x 2021-11-14 18:59:49 -08:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-11-20 10:35:54 -08:00
kernel - Prevent a tick storm when a dedicated timekeeper CPU in nohz_full 2021-12-05 08:58:52 -08:00
lib siphash: use _unaligned version by default 2021-11-29 19:50:50 -08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm Fixes for 5.16 folios: 2021-11-25 10:13:56 -08:00
net Networking fixes for 5.16-rc4, including fixes from wireless, 2021-12-02 11:22:06 -08:00
samples s390 updates for 5.16-rc2 2021-11-20 10:55:50 -08:00
scripts Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid 2021-11-24 09:44:13 -08:00
security selinux: fix NULL-pointer dereference when hashtab allocation fails 2021-11-19 16:11:39 -05:00
sound sound fixes for 5.16-rc4 2021-12-01 10:07:39 -08:00
tools tools build: Remove needless libpython-version feature check that breaks test-all fast path 2021-12-06 21:57:53 -03:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt KVM: downgrade two BUG_ONs to WARN_ON_ONCE 2021-11-26 06:43:28 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap MAINTAINERS: update email address of Christian Borntraeger 2021-11-18 17:50:54 +01:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS TTY/Serial fixes for 5.16-rc4 2021-12-05 09:13:20 -08:00
Makefile Makefile: Do not quote value for CONFIG_CC_IMPLICIT_FALLTHROUGH 2021-12-06 16:42:47 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.