On Wed, Sep 8, 2021 at 5:16 PM Prakash Sangappa <prakash.sangappa@xxxxxxxxxx> wrote: > > Including liunx-kernel.. > > Resending RFC. This patchset is not final. I am looking for feedback on > this proposal to share thread specific data for us in latency sensitive > codepath. Hi Prakash, I'd like to add here that Jann and I have been discussing a similar feature for my UMCG patchset: https://lore.kernel.org/lkml/CAG48ez0mgCXpXnqAUsa0TcFBPjrid-74Gj=xG8HZqj2n+OPoKw@xxxxxxxxxxxxxx/ In short, due to the need to read/write to the userspace from non-sleepable contexts in the kernel it seems that we need to have some form of per task/thread kernel/userspace shared memory that is pinned, similar to what your sys_task_getshared does. Do you think your sys_task_getshared can be tweaked to return an arbitrarily-sized block of memory (subject to overall constraints) rather than a fixed number of "options"? On a more general note, we have a kernel extension internally at Google, named "kuchannel", that is similar to what you propose here: per task/thread shared memory with counters and other stat fields that the kernel populates and the userspace reads (and some additional functionality that is not too relevant to the discussion). Thanks, Peter [...]
