2 Replies to “Three things to read”

  1. “Sweet Zombie Jesus.”

    It is April 1st, not Halloween. Why new Kerneltrap activity NOW? o_O

  2. The Linux BKL is a bit of a wacky thing. Originally its purpose was to allow at most one scheduling unit to be executing in kernel at one time. That’s not been the purpose for a long time though: the BKL is used by various random subsystems to synchronise stuff but much of the code doesn’t need to take it in order to execute safely in kernel space.

    The efforts to finally remove the BKL have been going on in some form or other for years. IIRC its behaviour includes the ability to be taken recursively and an automagical ability to release itself when a task is descheduled and then retake when the task is rescheduled. That makes it not an obviously easy fit for any of the other lock types one might otherwise replace it with. People can only remove it if they really understand the implications of the change.

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