Re: [PATCH] net/skbuff: silence warnings under memory pressure

From: Sergey Senozhatsky
Date: Wed Sep 04 2019 - 03:43:19 EST

On (09/04/19 16:19), Sergey Senozhatsky wrote:
> Hmm. I need to look at this more... wake_up_klogd() queues work only once
> on particular CPU: irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
> bool irq_work_queue()
> {
> /* Only queue if not already pending */
> if (!irq_work_claim(work))
> return false;
> __irq_work_queue_local(work);
> }

Plus one more check - waitqueue_active(&log_wait). printk() adds
pending irq_work only if there is a user-space process sleeping on
log_wait and irq_work is not already scheduled. If the syslog is
active or there is noone to wakeup then we don't queue irq_work.