On 9/28/23 12:46 AM, Amir Goldstein wrote: > I did not want to add an overlayfs specific workqueue for those > completions, because, as I'd mentioned before, I intend to move this > stacked file io infrastructure to common vfs code. > > I figured it's fine for overlayfs (or any stacked filesystem) to use its > own s_dio_done_wq for its own private needs. > > Please help me reassure that I got this right. Looks like you're creating it lazily as well, so probably fine to use the same wq rather than setup something new. > ret = -ENOMEM; > aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL); > if (!aio_req) Unrelated to this patch, but is this safe? You're allocating an aio_req from within the ->write_iter() handler, yet it's GFP_KERNEL? Seems like that should at least be GFP_NOFS, no? That aside, punting to a workqueue is a very heavy handed solution to the problem. Maybe it's the only one you have, didn't look too closely at it, but it's definitely not going to increase your performance... -- Jens Axboe
