On Tue, Feb 28, 2017 at 07:46:06PM -0800, Matthew Wilcox wrote: > Ugh, this is pretty inefficient. If that's all you want to know, then > using the radix tree directly will be far more efficient than spinning > up all the pagevec machinery only to discard the pages found. > > But what's going to kick these pages out of cache? Shouldn't we rather > find the pages, kick them out if clean, start writeback if not, and *then* > return -EAGAIN? > > So maybe we want to spin up the pagevec machinery after all so we can > do that extra work?
As pointed out in the last round of these patches I think we really need to pass a flags argument to filemap_write_and_wait_range to communicate the non-blocking nature and only return -EAGAIN if we'd block. As a bonus that can indeed start to kick the pages out.
