On 2025-03-14 11:27:40 [+0100], Vlastimil Babka wrote: > On 3/14/25 07:15, Shakeel Butt wrote: > > For non-PREEMPT_RT kernels, drain_obj_stock() is always called with irq > > disabled, so we can use __mod_memcg_state() instead of > > mod_memcg_state(). For PREEMPT_RT, we need to add memcg_stats_[un]lock > > in __mod_memcg_state(). > > > > Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx> > > Maybe it'll make sense later but as of this patch itself it begs a question > why put memcg_stats_lock()/unlock() in __mod_memcg_state itself and not just > around the call in drain_obj_stock()? The memcg_stats_lock() were introduce to protect the per-CPU counters (vmstats_percpu) on PREEMPT_RT which are protected on !PREEMPT_RT by disabling interrupts. Other modifier have this already except for __mod_memcg_state() because mod_memcg_state() was the only user and already disables interrupt for the operation. Sebastian
