[CRIU] [PATCH] lock: print a message if a futex is locked for more than 120 second

[Pavel Emelyanov]

On 11/12/2015 07:09 PM, Andrey Vagin wrote:
> From: Andrew Vagin <avagin at virtuozzo.com>
> 
> Signed-off-by: Andrew Vagin <avagin at virtuozzo.com>
> ---
>  include/lock.h | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/include/lock.h b/include/lock.h
> index 89d71b1..392318e 100644
> --- a/include/lock.h
> +++ b/include/lock.h
> @@ -39,12 +39,17 @@ static inline void futex_set(futex_t *f, u32 v)
>  		u32 tmp;					\
>  								\
>  		while (1) {					\
> +			struct timespec to = {.tv_sec = 120};	\
>  			tmp = (u32)atomic_read(&(__f)->raw);	\
>  			if ((tmp & FUTEX_ABORT_FLAG) ||		\
>  			    (tmp __cond (__v)))			\
>  				break;				\
>  			ret = sys_futex((u32 *)&(__f)->raw.counter, FUTEX_WAIT,\
> -					tmp, NULL, NULL, 0);	\
> +					tmp, &to, NULL, 0);	\
> +			if (ret == -ETIMEDOUT) {		\
> +				pr_warn("blocked for more than 120 seconds\n"); \

I guess it's not extremely informative. Can we add __file__ & __line__ from the
calling macros here?

> +				continue;			\
> +			}					\
>  			BUG_ON(ret < 0 && ret != -EWOULDBLOCK);	\
>  		}						\
>  	} while (0)
> @@ -84,20 +89,16 @@ static inline void futex_inc(futex_t *f) { atomic_inc(&f->raw); }
>  static inline void futex_dec(futex_t *f) { atomic_dec(&f->raw); }
>  
>  /* Wait until futex @f value become @v */
> -static inline void futex_wait_until(futex_t *f, u32 v)
> -{ futex_wait_if_cond(f, v, ==); }
> +#define futex_wait_until(f, v) futex_wait_if_cond(f, v, ==)
>  
>  /* Wait while futex @f value is greater than @v */
> -static inline void futex_wait_while_gt(futex_t *f, u32 v)
> -{ futex_wait_if_cond(f, v, <=); }
> +#define futex_wait_while_gt(f, v) futex_wait_if_cond(f, v, <=)
>  
>  /* Wait while futex @f value is less than @v */
> -static inline void futex_wait_while_lt(futex_t *f, u32 v)
> -{ futex_wait_if_cond(f, v, >=); }
> +#define futex_wait_while_lt(f, v) futex_wait_if_cond(f, v, >=)
>  
>  /* Wait while futex @f value is equal to @v */
> -static inline void futex_wait_while_eq(futex_t *f, u32 v)
> -{ futex_wait_if_cond(f, v, !=); }
> +#define futex_wait_while_eq(f, v) futex_wait_if_cond(f, v, !=)
>  
>  /* Wait while futex @f value is @v */
>  static inline void futex_wait_while(futex_t *f, u32 v)
>