On Mon, Aug 10, 2026 at 06:09:59PM +0200, Morten Brørup wrote: > > 3. Per-lcore caches: bounded LIFO stacks (no locks on the hot > > path). Cache misses trigger bulk transfers to/from the shared > > bin under a spinlock. > > I haven't looked at the v4 code in detail, so forgive me if my concern is > already addressed. > > I am worried that a non-EAL thread can be preempted while holding a fastmem > lock. > Could this cause an EAL thread to stall in the fastmem lib under the wrong > circumstances? > If so, can this be avoided in any way? > > The Lock-Free Stack has a solution using single-linked lists and a 128-bit > CAS operation. > The solution is quite slow (due to linked list traversal with retry on > collision), but progress is practically guaranteed. > This is an issue with many DPDK libraries, even rings and most mempool implementations. I think it's up to the app developer to ensure that preemption of non-EAL threads does not cause data-plane issues.
/Bruce
