Hi I have a case on a v4.14 kernel where the EXT4 journal commit disables preemption for 30ms due to jbd2_clear_buffer_revoked_flags(). That in turn disables preemption on other CPUs as they come to spin waiting for the same lock. The side-effect of that is that it periodically blocks high priority tasks from running. I see jbd2_clear_buffer_revoked_flags() iterating 32768 times calling __find_get_block(). Is there any way to make jbd2_clear_buffer_revoked_flags() take less time, or move its work out from under write_lock(&journal->j_state_lock)? Or do you have any other suggestions? Regards Adrian
