1 Nov
2023
1 Nov
'23
12:16 p.m.
On Wed, 1 Nov 2023, Hannes Reinecke wrote:
And that is something I've been wondering (for quite some time now): What _is_ the appropriate error handling for -ENOMEM? At this time, we assume it to be a retryable error and re-run the queue in the hope that things will sort itself out. But if they don't we're stuck. Can we somehow figure out if we make progress during submission, and (at least) issue a warning once we detect a stall?
The appropriate way is to use mempools. mempool_alloc (with __GFP_DIRECT_RECLAIM) can't ever fail.
But some kernel code does GFP_NOIO allocations in the I/O path and the authors hope that they get away with it.
Mikulas