On Tue, Aug 07, 2018 at 11:47:23AM -0700, Dennis Zhou wrote: > From: "Dennis Zhou (Facebook)" <dennisszhou@xxxxxxxxx> > > Currently, percpu memory only exposes allocation and utilization > information via debugfs. This more or less is only really useful for > understanding the fragmentation and allocation information at a > per-chunk level with a few global counters. This is also gated behind a > config. BPF and cgroup, for example, have seen an increase use causing > increased use of percpu memory. Let's make it easier for someone to > identify how much memory is being used. > > This patch adds the "Percpu" stat to meminfo to more easily look up how > much percpu memory is in use. This number includes the cost for all > allocated backing pages and not just isnight at the a unit, per chunk > level. Metadata is excluded. I think excluding metadata is fair because > the backing memory scales with the numbere of cpus and can quickly > outweigh the metadata. It also makes this calculation light. > > Signed-off-by: Dennis Zhou <dennisszhou@xxxxxxxxx> Acked-by: Roman Gushchin <guro@xxxxxx> It's super useful! I've seen hosts in production which have tens and hundreds on megabytes in per-cpu memory, and with vmalloc counters being defined to 0, it's really hard to notice and track down. Thanks, Dennis!
