On Thu, Oct 22, 2015 at 12:21:31AM -0400, Johannes Weiner wrote: > The tcp memory controller has extensive provisions for future memory > accounting interfaces that won't materialize after all. Cut the code > base down to what's actually used, now and in the likely future. > > - There won't be any different protocol counters in the future, so a > direct sock->sk_memcg linkage is enough. This eliminates a lot of > callback maze and boilerplate code, and restores most of the socket > allocation code to pre-tcp_memcontrol state. > > - There won't be a tcp control soft limit, so integrating the memcg In fact, the code is ready for the "soft" limit (I mean min, pressure, max tuple), it just lacks a knob. > code into the global skmem limiting scheme complicates things > unnecessarily. Replace all that with simple and clear charge and > uncharge calls--hidden behind a jump label--to account skb memory. > > - The previous jump label code was an elaborate state machine that > tracked the number of cgroups with an active socket limit in order > to enable the skmem tracking and accounting code only when actively > necessary. But this is overengineered: it was meant to protect the > people who never use this feature in the first place. Simply enable > the branches once when the first limit is set until the next reboot. > ... > @@ -1136,9 +1090,6 @@ static inline bool sk_under_memory_pressure(const struct sock *sk) > if (!sk->sk_prot->memory_pressure) > return false; > > - if (mem_cgroup_sockets_enabled && sk->sk_cgrp) > - return !!sk->sk_cgrp->memory_pressure; > - AFAIU, now we won't shrink the window on hitting the limit, i.e. this patch subtly changes the behavior of the existing knobs, potentially breaking them. Thanks, Vladimir -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
