On 11/20/18 at 6:38 PM, Waiman Long wrote: > On 11/20/2018 06:28 PM, Qian Cai wrote: > > The current value of the early boot static pool size is not big enough > > for systems with large number of CPUs with timer or/and workqueue > > objects selected. As the results, systems have 60+ CPUs with both timer > > and workqueue objects enabled could trigger "ODEBUG: Out of memory. > > ODEBUG disabled". Hence, fixed it by computing it according to > > CONFIG_NR_CPUS and CONFIG_DEBUG_OBJECTS_* options. > > > > Signed-off-by: Qian Cai <c...@gmx.us> > > --- > > Changes since v2: > > * Made the calculation easier to read suggested by long...@redhat.com. > > > > Changes since v1: > > * Removed the CONFIG_NR_CPUS check since it is always defined. > > * Introduced a minimal default pool size to start with. Otherwise, the pool > > size would be too low for systems only with a small number of CPUs. > > * Adjusted the scale factors according to data. > > > > lib/debugobjects.c | 82 ++++++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 80 insertions(+), 2 deletions(-) > > > > diff --git a/lib/debugobjects.c b/lib/debugobjects.c > > index 70935ed91125..02456a1e57cb 100644 > > --- a/lib/debugobjects.c > > +++ b/lib/debugobjects.c > > @@ -23,9 +23,82 @@ > > #define ODEBUG_HASH_BITS 14 > > #define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS) > > > > -#define ODEBUG_POOL_SIZE 1024 > > +#define ODEBUG_DEFAULT_POOL 512 > > #define ODEBUG_POOL_MIN_LEVEL 256 > > > > +/* > > + * Some debug objects are allocated during the early boot. Enabling some > > + * options like timers or workqueue objects may increase the size required > > + * significantly with large number of CPUs. For example (as today, 20 Nov. > > + * 2018), > > + * > > + * No. CPUs x 2 (worker pool) objects: > > + * > > + * start_kernel > > + * workqueue_init_early > > + * init_worker_pool > > + * init_timer_key > > + * debug_object_init > > + * > > + * No. CPUs objects (CONFIG_HIGH_RES_TIMERS): > > + * > > + * sched_init > > + * hrtick_rq_init > > + * hrtimer_init > > + * > > + * CONFIG_DEBUG_OBJECTS_WORK: > > + * No. CPUs x 6 (workqueue) objects: > > + * > > + * workqueue_init_early > > + * alloc_workqueue > > + * __alloc_workqueue_key > > + * alloc_and_link_pwqs > > + * init_pwq > > + * > > + * Also, plus No. CPUs objects: > > + * > > + * perf_event_init > > + * __init_srcu_struct > > + * init_srcu_struct_fields > > + * init_srcu_struct_nodes > > + * __init_work > > + * > > + * Increase the number a bit more in case the implmentatins are changed in > > + * the future, as it is better to avoid OOM than spending a bit more kernel > > + * memory that will/can be freed. > > + * > > + * With all debug objects config options selected except the workqueue and > > + * the timers, kernel reports, > > + * 64-CPU: ODEBUG: 4 of 4 active objects replaced > > + * 256-CPU: ODEBUG: 4 of 4 active objects replaced > > + * > > + * all the options except the workqueue: > > + * 64-CPU: ODEBUG: 466 of 466 active objects replaced > > + * 256-CPU: ODEBUG: 1810 of 1810 active objects replaced > > + * > > + * all the options except the timers: > > + * 64-CPU: ODEBUG: 652 of 652 active objects replaced > > + * 256-CPU: ODEBUG: 2572 of 2572 active objects replaced > > + * > > + * all the options: > > + * 64-CPU: ODEBUG: 1114 of 1114 active objects replaced > > + * 256-CPU: ODEBUG: 4378 of 4378 active objects replaced > > + */ > > +#ifdef CONFIG_DEBUG_OBJECTS_WORK > > +#define ODEBUG_WORK_PCPU_CNT 10 > > +#else > > +#define ODEBUG_WORK_PCPU_CNT 0 > > +#endif /* CONFIG_DEBUG_OBJECTS_WORK */ > > + > > +#ifdef CONFIG_DEBUG_OBJECTS_TIMERS > > +#define ODEBUG_TIMERS_PCPU_CNT 10 > > +#else > > +#define ODEBUG_TIMERS_PCPU_CNT 0 > > +#endif /* CONFIG_DEBUG_OBJECTS_TIMERS */ > > + > > +#define ODEBUG_POOL_SIZE (ODEBUG_DEFAULT_POOL + CONFIG_NR_CPUS * \ > > +(ODEBUG_TIMERS_PCPU_CNT + ODEBUG_WORK_PCPU_CNT)) > > Just a nit about indentation. There should be some indentation in the > continued line.
I am fine to add that, but checkpatch.pl complained that there should no spaces at the beginning of a newline. Guess we just ignore the warning? “please, no spaces at the start of a line”