5:22 a.m.
Martin Kletzander wrote:
On Sun, Nov 21, 2021 at 07:58:55PM +0400, Roman Bogorodskiy wrote:
>Recently, FreeBSD has got sched_get/setaffinity(3) implementations and
>the sched.h header as well [1]. To make these routines visible,
>users have to define _WITH_CPU_SET_T.
>
>This breaks current detection. Specifically, meson sees the
>sched_getaffinity() symbol and defines WITH_SCHED_GETAFFINITY. This
>define unlocks Linux implementation of virProcessSetAffinity() and other
>functions, which fails to build on FreeBSD because cpu_set_t is not
>visible as _WITH_CPU_SET_T is not defined.
>
>For now, change detection to the following:
>
> - Instead of checking sched_getaffinity(), check if 'cpu_set_t' is
> available through sched.h
> - Explicitly check the sched.h header instead of assuming its presence
> if WITH_SCHED_SETSCHEDULER is defined
>
Makes sense, although even the sched_getaffinity() is guarded by the new
_WITH_CPU_SET_T so there should be no error with the current code, am I
Nope, as I tried to explain in the commit message, the current code is
not working properly as it's using cc.has_function() for 'sched_getaffinity'
and this check passes because it's checking the specified function in
the standard library, so it works regardless of _WITH_CPU_SET_T. And as
it finds the sched_getaffinity(), the build still fails because we don't
set _WITH_CPU_SET_T.
right? And if I understand correctly we cannot use the FreeBSD
implementation as is because they do not have all the CPU_* macros we
need, right?
Frankly speaking, I haven't yet tested this implementation. Currently,
virprocess.c is using the original FreeBSD interface: cpuset_(get|set)affinity.
Generally, it would be a good thing to use the same implementation for
both Linux and FreeBSD, however, this Linux-compatible interface in
FreeBSD is not yet available in any FreeBSD release, so we'll have to keep
the old code for some time anyway, and also I need to test if it
actually works for us and figure out how to better detect and pass this _WITH_CPU_SET_T
with meson.
>1:
>https://cgit.freebsd.org/src/commit/?id=43736b71dd051212d5c55be9fa21c45993017fbb
>https://cgit.freebsd.org/src/commit/?id=160b4b922b6021848b6b48afc894d16b879b7af2
>https://cgit.freebsd.org/src/commit/?id=90fa9705d5cd29cf11c5dc7319299788dec2546a
>
>Signed-off-by: Roman Bogorodskiy <bogorodskiy(a)gmail.com>
>---
> meson.build | 4 +++-
> src/util/virprocess.c | 8 ++++----
> 2 files changed, 7 insertions(+), 5 deletions(-)
>
>diff --git a/meson.build b/meson.build
>index 9022bcfdc9..e4f36e8574 100644
>--- a/meson.build
>+++ b/meson.build
>@@ -553,7 +553,6 @@ functions = [
> 'posix_fallocate',
> 'posix_memalign',
> 'prlimit',
>- 'sched_getaffinity',
> 'sched_setscheduler',
> 'setgroups',
> 'setns',
>@@ -602,6 +601,7 @@ headers = [
> 'net/if.h',
> 'pty.h',
> 'pwd.h',
>+ 'sched.h',
> 'sys/auxv.h',
> 'sys/ioctl.h',
> 'sys/mount.h',
>@@ -671,6 +671,8 @@ symbols = [
>
> # Check for BSD approach for setting MAC addr
> [ 'net/if_dl.h', 'link_addr', '#include
<sys/types.h>\n#include <sys/socket.h>' ],
>+
>+ [ 'sched.h', 'cpu_set_t' ],
> ]
>
> if host_machine.system() == 'linux'
>diff --git a/src/util/virprocess.c b/src/util/virprocess.c
>index 6de3f36f52..81de90200e 100644
>--- a/src/util/virprocess.c
>+++ b/src/util/virprocess.c
>@@ -35,7 +35,7 @@
> # include <sys/time.h>
> # include <sys/resource.h>
> #endif
>-#if WITH_SCHED_SETSCHEDULER
>+#if WITH_SCHED_H
> # include <sched.h>
> #endif
>
>@@ -480,7 +480,7 @@ int virProcessKillPainfully(pid_t pid, bool force)
> return virProcessKillPainfullyDelay(pid, force, 0, false);
> }
>
>-#if WITH_SCHED_GETAFFINITY
>+#if WITH_DECL_CPU_SET_T
>
> int virProcessSetAffinity(pid_t pid, virBitmap *map, bool quiet)
> {
>@@ -626,7 +626,7 @@ virProcessGetAffinity(pid_t pid)
> return ret;
> }
>
>-#else /* WITH_SCHED_GETAFFINITY */
>+#else /* WITH_DECL_CPU_SET_T */
>
> int virProcessSetAffinity(pid_t pid G_GNUC_UNUSED,
> virBitmap *map G_GNUC_UNUSED,
>@@ -646,7 +646,7 @@ virProcessGetAffinity(pid_t pid G_GNUC_UNUSED)
> _("Process CPU affinity is not supported on this
platform"));
> return NULL;
> }
>-#endif /* WITH_SCHED_GETAFFINITY */
>+#endif /* WITH_DECL_CPU_SET_T */
>
>
> int virProcessGetPids(pid_t pid, size_t *npids, pid_t **pids)
>--
>2.33.1
>
Roman Bogorodskiy