On Tue, Jun 10, 2025 at 04:30:43PM +0100, Usama Arif wrote: > If we have 2 workloads on the same server, For e.g. one is database where THPs > just dont do well, but the other one is AI where THPs do really well. How > will the kernel monitor that the database workload is performing worse > and the AI one isnt? It can monitor the allocation/access patterns and see who's getting the benefit. The two workloads are in competition for memory, and we can tell which pages are hot and which cold. And I don't believe it's a binary anyway. I bet there are some allocations where the database benefits from having THPs (I mean, I know a database which invented the entire hugetlbfs subsystem so it could use PMD entries and avoid one layer of TLB misses!) > I added THP shrinker to hopefully try and do this automatically, and it does > really help. But unfortunately it is not a complete solution. > There are severely memory bound workloads where even a tiny increase > in memory will lead to an OOM. And if you colocate the container thats running > that workload with one in which we will benefit with THPs, we unfortunately > can't just rely on the system doing the right thing. Then maybe THP aren't for you. If your workloads are this sensitive, perhaps you should be using a mechanism which gives you complete control like hugetlbfs.
