[PATCHSET RFC] sched, jbd2: mark sleeps on journal->j_checkpoint_mutex as iowait

Hello, When there's heavy metadata operation traffic on ext4, the journal gets filled soon and majority of filesystem users end up blocking on journal->j_checkpoint_mutex with a stacktrace similar to the following. [] __jbd2_log_wait_for_space+0xb8/0x1d0 [] add_transaction_credits+0x286/0x2a0

[PATCHSET RFC] sched, jbd2: mark sleeps on journal->j_checkpoint_mutex as iowait

Hello, When there's heavy metadata operation traffic on ext4, the journal gets filled soon and majority of filesystem users end up blocking on journal->j_checkpoint_mutex with a stacktrace similar to the following. [] __jbd2_log_wait_for_space+0xb8/0x1d0 [] add_transaction_credits+0x286/0x2a0