On Tue, Jul 03, 2018 at 12:11:18PM +0800, Yang Shi wrote: > direct reclaim doesn't write out filesystem page, only kswapd could do > it. So, if the call comes from direct reclaim, it is definitely a bug. > > And, Mel Gormane also mentioned "Ultimately, this will be a BUG_ON." In > commit 94054fa3fca1fd78db02cb3d68d5627120f0a1d4 ("xfs: warn if direct > reclaim tries to writeback pages"). > > Although it is for xfs, ext4 has the similar behavior, so elevate > WARN_ON to BUG_ON. > > And, correct the comment accordingly. > > Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> > Cc: "Theodore Ts'o" <tytso@xxxxxxx> > Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx> > Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> What's the upside of crashing the kernel if the file sytsem can handle it? - Ted