[LSF/MM/BPF TOPIC] Replacing TASK_(UN)INTERRUPTIBLE with regions of uninterruptibility

[David Howells <dhowells@xxxxxxxxxx>]

Hi,

We have various locks, mutexes, etc., that are taken on entry to filesystem
code, for example, and a bunch of them are taken interruptibly or killably (or
ought to be) - but filesystem code might be called into from uninterruptible
code, such as the memory allocator, fscache, etc..

Does it make sense to replace TASK_{INTERRUPTIBLE,KILLABLE,UNINTERRUPTIBLE}
with begin/end functions that define the area of uninterruptibility?  The
regions would need to handle being nested, so maybe some sort of counter in
the task_struct counter would work.

David