Vlastimil Babka wrote: > On 09/13/2017 03:54 PM, Tetsuo Handa wrote: > > Michal Hocko wrote: > >> Let's see what others think about this. > > > > Whether __GFP_NOWARN should warn about stalls is not a topic to discuss. > > It is the topic of this thread, which tries to address a concrete > problem somebody has experienced. In that context, the rest of your > concerns seem to me not related to this problem, IMHO.
I suggested replacing warn_alloc() with safe/useful one rather than tweaking warn_alloc() about __GFP_NOWARN. > > > I consider warn_alloc() for reporting stalls is broken. It fails to provide > > backtrace of stalling location. For example, OOM lockup with oom_lock held > > cannot be reported by warn_alloc(). It fails to provide readable output when > > called concurrently. For example, concurrent calls can cause printk()/ > > schedule_timeout_killable() lockup with oom_lock held. printk() offloading > > is > > not an option, for there will be situations where printk() offloading cannot > > be used (e.g. queuing via printk() is faster than writing to serial consoles > > which results in unreadable logs due to log_bug overflow).
