On Tue 14-01-20 16:40:49, Qian Cai wrote: > > > > On Jan 14, 2020, at 4:02 PM, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > > Yeah, that was a long discussion with a lot of lockdep false positives. > > I believe I have made it clear that the console code shouldn't depend on > > memory allocation because that is just too fragile. If that is not > > possible for some reason then it has to be mentioned in the changelog. > > I really do not want us to add kludges to the MM code just because of > > printk deficiencies unless that is absolutely inevitable. > > I don’t know how to convince you, but both random number generator > and printk() maintainers agreed to get ride of printk() with > zone->lock held as you can see in the approved commit mentioned in > this patch description because it is a whac-a-mole to fix other > places. I really do not understand this argument. It is quite a specific path in the console code which cannot allocate any memory or use locks which depend on the allocation via a lock chain, right? So how come this is a whack a mole? Also any console that really needs GFP_ATOMIC to write something out is just inherently broken so it should better be fixed rather than worked around. -- Michal Hocko SUSE Labs
