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    Subject[PATCH v3 06/18] powerpc/vas: Reduce polling interval for busy state
    Date
    A VAS window is normally in "busy" state for only a short duration.
    Reduce the time we wait for the window to go to "not-busy" state to
    speed-up vas_win_close() a bit.

    Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
    ---
    arch/powerpc/platforms/powernv/vas-window.c | 10 ++++++----
    1 file changed, 6 insertions(+), 4 deletions(-)

    diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
    index 95622a9..1422cdd 100644
    --- a/arch/powerpc/platforms/powernv/vas-window.c
    +++ b/arch/powerpc/platforms/powernv/vas-window.c
    @@ -1060,21 +1060,23 @@ int vas_paste_crb(struct vas_window *txwin, int offset, bool re)
    }
    EXPORT_SYMBOL_GPL(vas_paste_crb);

    +/*
    + * Wait for the window to go to "not-busy" state. It should only take a
    + * short time to queue a CRB, so window should not be busy for too long.
    + * Trying 5ms intervals.
    + */
    static void poll_window_busy_state(struct vas_window *window)
    {
    int busy;
    u64 val;

    retry:
    - /*
    - * Poll Window Busy flag
    - */
    val = read_hvwc_reg(window, VREG(WIN_STATUS));
    busy = GET_FIELD(VAS_WIN_BUSY, val);
    if (busy) {
    val = 0;
    set_current_state(TASK_UNINTERRUPTIBLE);
    - schedule_timeout(HZ);
    + schedule_timeout(msecs_to_jiffies(5));
    goto retry;
    }
    }
    --
    2.7.4
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