haad <[email protected]> wrote: > ad@ > KM_NOSLEEP... probably due to that implying UVM_MAP_TRYLOCK > The issue is that parts of kernel_map are pageable. Paging can take a > long time, and the map can be held locked while paging. > > Therefore when we do a NOSLEEP allocation from kernel_map, it's also > implicitly a TRYLOCK one because we can't wait to lock the map.
FYI: Related problem is described in PR/38270. In this case, I guess kmem_map, which is used by pool(9) and is VM_MAP_INTRSAFE, could avoid trylock because map is locked by a spin-mutex (at IPL_VM). It is not the case for kernel_map (at IPL_DEFAULT), used by kmem(9). There is yamt-kmem branch which has been revamping this. yamt? -- Mindaugas
