On 7/28/20 3:58 PM, Daniel Vetter wrote:
GPU drivers need this in their shrinkers, to be able to throw out
mmap'ed buffers. Note that we also need dma_resv_lock in shrinkers,
but that loop is resolved by trylocking in shrinkers.
So full hierarchy is now (ignore some of the other branches we already
have primed):
mmap_read_lock -> dma_resv -> shrinkers -> i_mmap_lock_write
I hope that's not inconsistent with anything mm or fs does, adding
relevant people.
Looks OK to me. The mapping_dirty_helpers run under the i_mmap_lock, but
don't allocate any memory AFAICT.
Since huge page-table-entry splitting may happen under the i_mmap_lock
from unmap_mapping_range() it might be worth figuring out how new page
directory pages are allocated, though.
/Thomas
