diff options
| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2018-11-27 11:03:21 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2019-05-02 09:02:16 +0200 |
| commit | 1136764dd9fba7be7123bf5c23a4d1e507e4f7e1 (patch) | |
| tree | 9fbba29b53d87c60d1cecd1e201a18b8efa0f026 | |
| parent | 2ccd55b269e750f1499dac5714e5d06f9f103cfc (diff) | |
kernel.h: Add non_block_start/end()
In some special cases we must not block, but there's not a
spinlock, preempt-off, irqs-off or similar critical section already
that arms the might_sleep() debug checks. Add a non_block_start/end()
pair to annotate these.
This will be used in the oom paths of mmu-notifiers, where blocking is
not allowed to make sure there's forward progress.
Suggested by Michal Hocko.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: linux-mm@kvack.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
| -rw-r--r-- | include/linux/kernel.h | 10 | ||||
| -rw-r--r-- | include/linux/sched.h | 4 | ||||
| -rw-r--r-- | kernel/sched/core.c | 6 |
3 files changed, 16 insertions, 4 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2d14e21c16c0..0bfdf56803b4 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -224,7 +224,9 @@ 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 @@ -240,6 +242,10 @@ 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) +# define non_block_start() \ + do { current->non_block_count++; } while (0) +# define non_block_end() \ + do { WARN_ON(current->non_block_count-- == 0); } while (0) #else static inline void ___might_sleep(const char *file, int line, int preempt_offset) { } @@ -248,6 +254,8 @@ 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) diff --git a/include/linux/sched.h b/include/linux/sched.h index 1549584a1538..1eb24b39e90e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -907,6 +907,10 @@ struct task_struct { struct mutex_waiter *blocked_on; #endif +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP + int non_block_count; +#endif + #ifdef CONFIG_TRACE_IRQFLAGS unsigned int irq_events; unsigned long hardirq_enable_ip; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4778c48a7fda..e173eccae85e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6155,7 +6155,7 @@ void ___might_sleep(const char *file, int line, int preempt_offset) rcu_sleep_check(); if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && - !is_idle_task(current)) || + !is_idle_task(current) && !current->non_block_count) || system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING || oops_in_progress) return; @@ -6171,8 +6171,8 @@ void ___might_sleep(const char *file, int line, int preempt_offset) "BUG: sleeping function called from invalid context at %s:%d\n", file, line); printk(KERN_ERR - "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", - in_atomic(), irqs_disabled(), + "in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n", + in_atomic(), irqs_disabled(), current->non_block_count, current->pid, current->comm); if (task_stack_end_corrupted(current)) |