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  1. 10 Oct, 2023 5 commits
  3. 09 Oct, 2023 9 commits
  5. 07 Oct, 2023 7 commits
  7. 05 Oct, 2023 1 commit
    • Xuewen Yan's avatar
      cpufreq: schedutil: Update next_freq when cpufreq_limits change · 9e0bc36a
      Xuewen Yan authored 
      When cpufreq's policy is 'single', there is a scenario that will
cause sg_policy's next_freq to be unable to update.

When the CPU's util is always max, the cpufreq will be max,
and then if we change the policy's scaling_max_freq to be a
lower freq, indeed, the sg_policy's next_freq need change to
be the lower freq, however, because the cpu_is_busy, the next_freq
would keep the max_freq.

For example:

The cpu7 is a single CPU:

  unisoc:/sys/devices/system/cpu/cpufreq/policy7 # while true;do done& [1] 4737
  unisoc:/sys/devices/system/cpu/cpufreq/policy7 # taskset -p 80 4737
  pid 4737's current affinity mask: ff
  pid 4737's new affinity mask: 80
  unisoc:/sys/devices/system/cpu/cpufreq/policy7 # cat scaling_max_freq
  2301000
  unisoc:/sys/devices/system/cpu/cpufreq/policy7 # cat scaling_cur_freq
  2301000
  unisoc:/sys/devices/system/cpu/cpufreq/policy7 # echo 2171000 > scaling_max_freq
  unisoc:/sys/devices/system/cpu/cpufreq/policy7 # cat scaling_max_freq
  2171000

At this time, the sg_policy's next_freq would stay at 2301000, which
is wrong.

To fix this, add a check for the ->need_freq_update flag.

[ mingo: Clarified the changelog. ]
Co-developed-by: default avatarGuohua Yan <guohua.yan@unisoc.com>
Signed-off-by: default avatarXuewen Yan <xuewen.yan@unisoc.com>
Signed-off-by: default avatarGuohua Yan <guohua.yan@unisoc.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatar"Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230719130527.8074-1-xuewen.yan@unisoc.com
      9e0bc36a
  9. 03 Oct, 2023 3 commits
  11. 02 Oct, 2023 4 commits
    • Kir Kolyshkin's avatar
      sched/headers: Move 'struct sched_param' out of uapi, to work around glibc/musl breakage · d844fe65
      Kir Kolyshkin authored 
      Both glibc and musl define 'struct sched_param' in sched.h, while kernel
has it in uapi/linux/sched/types.h, making it cumbersome to use
sched_getattr(2) or sched_setattr(2) from userspace.

For example, something like this:

	#include <sched.h>
	#include <linux/sched/types.h>

	struct sched_attr sa;

will result in "error: redefinition of ‘struct sched_param’" (note the
code doesn't need sched_param at all -- it needs struct sched_attr
plus some stuff from sched.h).

The situation is, glibc is not going to provide a wrapper for
sched_{get,set}attr, thus the need to include linux/sched_types.h
directly, which leads to the above problem.

Thus, the userspace is left with a few sub-par choices when it wants to
use e.g. sched_setattr(2), such as maintaining a copy of struct
sched_attr definition, or using some other ugly tricks.

OTOH, 'struct sched_param' is well known, defined in POSIX, and it won't
be ever changed (as that would break backward compatibility).

So, while 'struct sched_param' is indeed part of the kernel uapi,
exposing it the way it's done now creates an issue, and hiding it
(like this patch does) fixes that issue, hopefully without creating
another one: common userspace software rely on libc headers, and as
for "special" software (like libc), it looks like glibc and musl
do not rely on kernel headers for 'struct sched_param' definition
(but let's Cc their mailing lists in case it's otherwise).

The alternative to this patch would be to move struct sched_attr to,
say, linux/sched.h, or linux/sched/attr.h (the new file).

Oh, and here is the previous attempt to fix the issue:

  https://lore.kernel.org/all/20200528135552.GA87103@google.com/

While I support Linus arguments, the issue is still here
and needs to be fixed.

[ mingo: Linus is right, this shouldn't be needed - but on the other
         hand I agree that this header is not really helpful to
	 user-space as-is. So let's pretend that
	 <uapi/linux/sched/types.h> is only about sched_attr, and
	 call this commit a workaround for user-space breakage
	 that it in reality is ... Also, remove the Fixes tag. ]
Signed-off-by: default avatarKir Kolyshkin <kolyshkin@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230808030357.1213829-1-kolyshkin@gmail.com
      d844fe65
    • Cyril Hrubis's avatar
      sched/rt/docs: Use 'real-time' instead of 'realtime' · 83494dc5
      Cyril Hrubis authored 
      Standardize on a single variant.
Signed-off-by: default avatarCyril Hrubis <chrubis@suse.cz>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231002115553.3007-4-chrubis@suse.cz
      83494dc5
    • Cyril Hrubis's avatar
      sched/rt/docs: Clarify & fix sched_rt_* sysctl docs · e6dbdd8f
      Cyril Hrubis authored 
      - Describe explicitly that sched_rt_runtime_us is allocated from
  sched_rt_period_us and hence always less or equal to that value.

- The limit for sched_rt_runtime_us is not INT_MAX-1, but rather it's
  limited by the value of sched_rt_period_us. If sched_rt_period_us is
  INT_MAX then sched_rt_runtime_us can be set to INT_MAX as well.
Signed-off-by: default avatarCyril Hrubis <chrubis@suse.cz>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231002115553.3007-3-chrubis@suse.cz
      e6dbdd8f
    • Cyril Hrubis's avatar
      sched/rt: Disallow writing invalid values to sched_rt_period_us · 079be8fc
      Cyril Hrubis authored 
      The validation of the value written to sched_rt_period_us was broken
because:

  - the sysclt_sched_rt_period is declared as unsigned int
  - parsed by proc_do_intvec()
  - the range is asserted after the value parsed by proc_do_intvec()

Because of this negative values written to the file were written into a
unsigned integer that were later on interpreted as large positive
integers which did passed the check:

  if (sysclt_sched_rt_period <= 0)
	return EINVAL;

This commit fixes the parsing by setting explicit range for both
perid_us and runtime_us into the sched_rt_sysctls table and processes
the values with proc_dointvec_minmax() instead.

Alternatively if we wanted to use full range of unsigned int for the
period value we would have to split the proc_handler and use
proc_douintvec() for it however even the
Documentation/scheduller/sched-rt-group.rst describes the range as 1 to
INT_MAX.

As far as I can tell the only problem this causes is that the sysctl
file allows writing negative values which when read back may confuse
userspace.

There is also a LTP test being submitted for these sysctl files at:

  http://patchwork.ozlabs.org/project/ltp/patch/20230901144433.2526-1-chrubis@suse.cz/Signed-off-by: default avatarCyril Hrubis <chrubis@suse.cz>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231002115553.3007-2-chrubis@suse.cz
      079be8fc
  13. 01 Oct, 2023 11 commits
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