On Wed, Jul 31, 2024 at 5:50 AM Yunsheng Lin <linyunsheng@xxxxxxxxxx> wrote: > > Basing on the lib/objpool.c, change it to something like a > ptrpool, so that we can utilize that to test the correctness > and performance of the page_frag. > > The testing is done by ensuring that the fragment allocated > from a frag_frag_cache instance is pushed into a ptrpool > instance in a kthread binded to a specified cpu, and a kthread > binded to a specified cpu will pop the fragment from the > ptrpool and free the fragment. > > We may refactor out the common part between objpool and ptrpool > if this ptrpool thing turns out to be helpful for other place. This isn't a patch where you should be introducing stuff you hope to refactor out and reuse later. Your objpoo/ptrpool stuff is just going to add bloat and overhead as you are going to have to do pointer changes to get them in and out of memory and you are having to scan per-cpu lists. You would be better served using a simple array as your threads should be stick to a consistent CPU anyway in terms of testing. I would suggest keeping this much more simple. Trying to pattern this after something like the dmapool_test code would be a better way to go for this. We don't need all this extra objpool overhead getting in the way of testing the code you should be focused on. Just allocate your array on one specific CPU and start placing and removing your pages from there instead of messing with the push/pop semantics. Lastly something that is a module only tester that always fails to probe doesn't sound like it really makes sense as a standard kernel module. I still think it would make more sense to move it to the selftests tree and just have it build there as a module instead of trying to force it into the mm tree. The example of dmapool_test makes sense as it could be run at early boot to run the test and then it just goes quiet. This module won't load and will always just return -EAGAIN which doesn't sound like a valid kernel module to me.
