Amir Goldstein <amir73il@xxxxxxxxx> writes: > On Tue, Apr 19, 2022 at 6:29 PM Gabriel Krisman Bertazi > <krisman@xxxxxxxxxxxxx> wrote: >> > Well that sucks. We need a kernel-side workaround for applications >> > that fail to check and report storage errors? >> > >> > We could do this for every syscall in the kernel. What's special about >> > tmpfs in this regard? >> > >> > Please provide additional justification and usage examples for such an >> > extraordinary thing. >> >> For a cloud provider deploying containerized applications, they might >> not control the application, so patching userspace wouldn't be a >> solution. More importantly - and why this is shmem specific - >> they want to differentiate between a user getting ENOSPC due to >> insufficiently provisioned fs size, vs. due to running out of memory in >> a container, both of which return ENOSPC to the process. >> > > Isn't there already a per memcg OOM handler that could be used by > orchestrator to detect the latter? Hi Amir, Thanks for the added context. I'm actually not sure if an OOM handler completely solves the latter case. If shmem_inode_acct_block fails, it happens before the allocation. The OOM won't trigger and we won't know about it, as far as I understand. I'm not sure it's real problem for Google's use case. Khazhy is the expert on their implementation and might be able to better discuss it. I wanna mention that, for the insufficiently-provisioned-fs-size case, we still can't rely just on statfs. We need a polling interface - generic or tmpfs specific - to make sure we don't miss these events, I think. Thanks, -- Gabriel Krisman Bertazi
