On Wed, Aug 09, 2017 at 11:38:49AM -0500, Steve Wise wrote: > > On Wed, Aug 09, 2017 at 11:21:38AM -0500, Steve Wise wrote: > > > > > > I don't know. I read the workqueue doc on WQ_MEM_RECLAIM, but I don't > > know > > > > how > > > > to tell if iw_cm needs this or not. Can you give me an example of a > workqueue > > > > that _does_ need WQ_MEM_RECLAIM? I _think_ it means your workqueue is > > > > required > > > > to run something that would get triggered by the oom OS code, but I don't > know > > > > if that would include rdma CMs or not... > > > > > > Many of the workqueues in infiniband/core use WQ_MEM_RECLAIM: cma, iwcm, > > mad, > > > multicast, sa_query, and ucma. > > > > > > Hey Sean, do you have any insight into whether the CMA modules really need > > > WQ_MEM_RECLAIM for their workqueues? > > > > > > Does anyone else know? > > > > Consider that the ib_core can be used to back storage. Ie consider a > > situation where iSER/NFS/SRP needs to reconnect to respond to kernel > > paging/reclaim. > > > > On the surface it seems reasonable to me that these are on a reclaim > > path? > > > > Jason > > hmm. That seems reasonable. Then I would think the nvme_rdma would also need > to be using a reclaim workqueue. > > Sagi, Do you think I should add a private workqueue with WQ_MEM_RECLAIM to > nvme_rdma vs using the system_wq? nvme/target probably needs one also... The workqueue which frees the memory and doesn't allocate memory during execution is supposed to be marked as WQ_MEM_RECLAIM. This flag will cause to priority increase for such workqueue during low memory conditions. I don't remember it for sure, but I think that shrinker will call to such workqueue in these conditions. In normal conditions, it won't change a lot. Thanks > > Steve. > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html
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