• Jaewon Kim's avatar
    ratelimit: fix bug in time interval by resetting right begin time · c2594bc3
    Jaewon Kim authored
    rs->begin in ratelimit is set in two cases.
     1) when rs->begin was not initialized
     2) when rs->interval was passed
    
    For case #2, current ratelimit sets the begin to 0.  This incurrs
    improper suppression.  The begin value will be set in the next ratelimit
    call by 1).  Then the time interval check will be always false, and
    rs->printed will not be initialized.  Although enough time passed,
    ratelimit may return 0 if rs->printed is not less than rs->burst.  To
    reset interval properly, begin should be jiffies rather than 0.
    
    For an example code below:
    
        static DEFINE_RATELIMIT_STATE(mylimit, 1, 1);
        for (i = 1; i <= 10; i++) {
            if (__ratelimit(&mylimit))
                printk("ratelimit test count %d\n", i);
            msleep(3000);
        }
    
    test result in the current code shows suppression even there is 3 seconds sleep.
    
      [  78.391148] ratelimit test count 1
      [  81.295988] ratelimit test count 2
      [  87.315981] ratelimit test count 4
      [  93.336267] ratelimit test count 6
      [  99.356031] ratelimit test count 8
      [ 105.376367] ratelimit test count 10
    Signed-off-by: default avatarJaewon Kim <jaewon31.kim@samsung.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    c2594bc3
ratelimit.c 1.54 KB