Re: [PATCH 50/50] Kill sched.h dependency on rcupdate.h

[Geert Uytterhoeven]

Hi Kent,

On Sat, Dec 16, 2023 at 4:39 AM Kent Overstreet
<kent.overstreet@xxxxxxxxx> wrote:
> by moving cond_resched_rcu() to rcupdate.h, we can kill another big
> sched.h dependency.
>
> Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>

Thanks for your patch, which is now commit dc00f26faea81dc0 ("Kill
sched.h dependency on rcupdate.h") in next-20231220.

Reported-by: noreply@xxxxxxxxxxxxxx

$ make ARCH=m68k defconfig arch/m68k/kernel/asm-offsets.i
*** Default configuration is based on 'multi_defconfig'
#
# No change to .config
#
  UPD     include/config/kernel.release
  UPD     include/generated/utsrelease.h
  CC      arch/m68k/kernel/asm-offsets.s
In file included from ./include/asm-generic/bug.h:7,
                 from ./arch/m68k/include/asm/bug.h:32,
                 from ./include/linux/bug.h:5,
                 from ./include/linux/thread_info.h:13,
                 from ./arch/m68k/include/asm/processor.h:11,
                 from ./include/linux/sched.h:13,
                 from arch/m68k/kernel/asm-offsets.c:15:
./arch/m68k/include/asm/processor.h: In function ‘set_fc’:
./arch/m68k/include/asm/processor.h:91:15: error: implicit declaration
of function ‘in_interrupt’ [-Werror=implicit-function-declaration]
   91 |  WARN_ON_ONCE(in_interrupt());
      |               ^~~~~~~~~~~~
./include/linux/once_lite.h:28:27: note: in definition of macro
‘DO_ONCE_LITE_IF’
   28 |   bool __ret_do_once = !!(condition);   \
      |                           ^~~~~~~~~
./arch/m68k/include/asm/processor.h:91:2: note: in expansion of macro
‘WARN_ON_ONCE’
   91 |  WARN_ON_ONCE(in_interrupt());
      |  ^~~~~~~~~~~~
cc1: some warnings being treated as errors
make[3]: *** [scripts/Makefile.build:116:
arch/m68k/kernel/asm-offsets.s] Error 1
make[2]: *** [Makefile:1191: prepare0] Error 2
make[1]: *** [Makefile:350: __build_one_by_one] Error 2
make: *** [Makefile:234: __sub-make] Error 2

> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -1058,4 +1058,15 @@ extern int rcu_normal;
>
>  DEFINE_LOCK_GUARD_0(rcu, rcu_read_lock(), rcu_read_unlock())
>
> +#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
> +#define cond_resched_rcu()             \
> +do {                                   \
> +       rcu_read_unlock();              \
> +       cond_resched();                 \
> +       rcu_read_lock();                \
> +} while (0)
> +#else
> +#define cond_resched_rcu()
> +#endif
> +
>  #endif /* __LINUX_RCUPDATE_H */
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index d528057c99e4..b781ac7e0a02 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -10,8 +10,11 @@
>  #include <uapi/linux/sched.h>
>
>  #include <asm/current.h>
> +#include <linux/thread_info.h>
> +#include <linux/preempt.h>
>
>  #include <linux/irqflags_types.h>
> +#include <linux/smp_types.h>
>  #include <linux/pid_types.h>
>  #include <linux/sem_types.h>
>  #include <linux/shm.h>
> @@ -22,7 +25,6 @@
>  #include <linux/timer_types.h>
>  #include <linux/seccomp_types.h>
>  #include <linux/nodemask_types.h>
> -#include <linux/rcupdate.h>
>  #include <linux/refcount_types.h>
>  #include <linux/resource.h>
>  #include <linux/latencytop.h>
> @@ -2058,15 +2060,6 @@ extern int __cond_resched_rwlock_write(rwlock_t *lock);
>         __cond_resched_rwlock_write(lock);                                      \
>  })
>
> -static inline void cond_resched_rcu(void)
> -{
> -#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
> -       rcu_read_unlock();
> -       cond_resched();
> -       rcu_read_lock();
> -#endif
> -}
> -
>  #ifdef CONFIG_PREEMPT_DYNAMIC
>
>  extern bool preempt_model_none(void);

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds