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    SubjectRe: [patch V3 48/64] locking/ww_mutex: Add RT priority to W/W order
    Date
    On Fri, Aug 06 2021 at 12:48, Peter Zijlstra wrote:

    > On Thu, Aug 05, 2021 at 05:13:48PM +0200, Thomas Gleixner wrote:
    >> static inline bool
    >> +__ww_ctx_less(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b)
    >> {
    >> +/*
    >> + * Can only do the RT prio for WW_RT because task->prio isn't stable due to PI,
    >> + * so the wait_list ordering will go wobbly. rt_mutex re-queues the waiter and
    >> + * isn't affected by this.
    >> + */
    >> +#ifdef WW_RT
    >> + /* kernel prio; less is more */
    >> + int a_prio = a->task->prio;
    >> + int b_prio = b->task->prio;
    >> +
    >> + if (dl_prio(a_prio) || dl_prio(b_prio)) {
    >
    > Whoever wrote this was an idiot :-) Both should be rt_prio().

    Along with the idiot who picked that up and stared at it for quite some
    time.

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      Last update: 2021-08-06 13:51    [W:4.935 / U:0.476 seconds]
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