Thanks, I will take a look. Regards, Kenny On Wed, Feb 19, 2020 at 1:38 PM Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > On Wed, Feb 19, 2020 at 11:28:48AM -0500, Kenny Ho wrote: > > On Wed, Feb 19, 2020 at 11:18 AM Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > > > > > Yes, I'd go with absolute units when it comes to memory, because it's > > > not a renewable resource like CPU and IO, and so we do have cliff > > > behavior around the edge where you transition from ok to not-enough. > > > > > > memory.low is a bit in flux right now, so if anything is unclear > > > around its semantics, please feel free to reach out. > > > > I am not familiar with the discussion, would you point me to a > > relevant thread please? > > Here is a cleanup patch, not yet merged, that documents the exact > semantics and behavioral considerations: > > https://lore.kernel.org/linux-mm/20191213192158.188939-3-hannes@xxxxxxxxxxx/ > > But the high-level idea is this: you assign each cgroup or cgroup > subtree a chunk of the resource that it's guaranteed to be able to > consume. It *can* consume beyond that threshold if available, but that > overage may get reclaimed again if somebody else needs it instead. > > This allows you to do a ballpark distribution of the resource between > different workloads, while the kernel retains the ability to optimize > allocation of spare resources - because in practice, workload demand > varies over time, workloads disappear and new ones start up etc. > > > In addition, is there some kind of order of preference for > > implementing low vs high vs max? > > If you implement only one allocation model, the preference would be on > memory.low. Limits are rigid and per definition waste resources, so in > practice we're moving away from them.
