diff options
Diffstat (limited to 'include/linux/kernel.h')
| -rw-r--r-- | include/linux/kernel.h | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 4fa360a13c1e..d83d403dac2e 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -217,7 +217,9 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset); * might_sleep - annotation for functions that can sleep * * this macro will print a stack trace if it is executed in an atomic - * context (spinlock, irq-handler, ...). + * context (spinlock, irq-handler, ...). Additional sections where blocking is + * not allowed can be annotated with non_block_start() and non_block_end() + * pairs. * * This is a useful debugging help to be able to catch problems early and not * be bitten later when the calling function happens to sleep when it is not @@ -233,6 +235,23 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset); # define cant_sleep() \ do { __cant_sleep(__FILE__, __LINE__, 0); } while (0) # define sched_annotate_sleep() (current->task_state_change = 0) +/** + * non_block_start - annotate the start of section where sleeping is prohibited + * + * This is on behalf of the oom reaper, specifically when it is calling the mmu + * notifiers. The problem is that if the notifier were to block on, for example, + * mutex_lock() and if the process which holds that mutex were to perform a + * sleeping memory allocation, the oom reaper is now blocked on completion of + * that memory allocation. Other blocking calls like wait_event() pose similar + * issues. + */ +# define non_block_start() (current->non_block_count++) +/** + * non_block_end - annotate the end of section where sleeping is prohibited + * + * Closes a section opened by non_block_start(). + */ +# define non_block_end() WARN_ON(current->non_block_count-- == 0) #else static inline void ___might_sleep(const char *file, int line, int preempt_offset) { } @@ -241,6 +260,8 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset); # define might_sleep() do { might_resched(); } while (0) # define cant_sleep() do { } while (0) # define sched_annotate_sleep() do { } while (0) +# define non_block_start() do { } while (0) +# define non_block_end() do { } while (0) #endif #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) |