On Tue, Aug 26, 2025 at 09:42:30AM +0200, David Hildenbrand wrote: > On 26.08.25 09:19, Yafang Shao wrote: > > Background > > ========== > > > > Our production servers consistently configure THP to "never" due to > > historical incidents caused by its behavior. Key issues include: > > - Increased Memory Consumption > > THP significantly raises overall memory usage, reducing available memory > > for workloads. > > > > - Latency Spikes > > Random latency spikes occur due to frequent memory compaction triggered > > by THP. > > > > - Lack of Fine-Grained Control > > THP tuning is globally configured, making it unsuitable for containerized > > environments. When multiple workloads share a host, enabling THP without > > per-workload control leads to unpredictable behavior. > > > > Due to these issues, administrators avoid switching to madvise or always > > modes—unless per-workload THP control is implemented. > > > > To address this, we propose BPF-based THP policy for flexible adjustment. > > Additionally, as David mentioned [0], this mechanism can also serve as a > > policy prototyping tool (test policies via BPF before upstreaming them). > > There is a lot going on and most reviewers (including me) are fairly busy > right now, so getting more detailed review could take a while. > > This topic sounds like a good candidate for the bi-weekly MM alignment > session. > > Would you be interested in presenting the current bpf interface, how to use > it, drawbacks, todos, ... in that forum? > > David Rientjes, who organizes this meeting, is already on Cc. If we do this, would like an invite to it also! Have been meaning to take a look into this in detail while in RFC but more so now obviously :) as discussed in THP cabal, I am broadly in favour of this as long we get the interface right. Anyway let me have a look through...! Cheers, Lorenzo
