On Sat, 26 Jul 2014, Taylor R Campbell wrote:
Make Linux usecs_to_jiffies work with hz up to 2000.
usecs_to_jiffies(unsigned int usec)
{
- return mstohz((usec + (1000 / hz) - 1) / (1000 / hz));
+ if (hz <= 100)
+ return mstohz(roundup(usec, (1000 / hz)));
+
+ /*
+ * Avoid integer overflow on 32-bit platforms. The cutoff is
+ * kinda arbitrary; for hz <= 2000, 0x200000 is safe, but both
+ * values could wiggle around a little.
+ */
+ KASSERT(hz <= 2000);
+ if (usec <= 0x200000)
+ return ((usec * hz) / 1000000);
+ else
+ return ((usec / 1000000) * hz);
}
You could just populate a struct timeval, and call tvtohz(9).What is the desired behaviour for small inputs? The code quoted above appears to round up when hz <= 100 (and to return 1 for very small but non-zero inputs) but to round down (and to return 0 for very small inputs) when hz > 100. Once the desired behaviour is clarified, you could implement it by making adjustments to the value before or after calling tvtohz.
--apb (Alan Barrett)