diff options
| -rw-r--r-- | kernel/sched.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 5470ab0258a..b0afd8db139 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -638,6 +638,11 @@ static u64 div64_likely32(u64 divident, unsigned long divisor) #define WMULT_SHIFT 32 +/* + * Shift right and round: + */ +#define RSR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) + static unsigned long calc_delta_mine(unsigned long delta_exec, unsigned long weight, struct load_weight *lw) @@ -645,18 +650,17 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight, u64 tmp; if (unlikely(!lw->inv_weight)) - lw->inv_weight = WMULT_CONST / lw->weight; + lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1; tmp = (u64)delta_exec * weight; /* * Check whether we'd overflow the 64-bit multiplication: */ - if (unlikely(tmp > WMULT_CONST)) { - tmp = ((tmp >> WMULT_SHIFT/2) * lw->inv_weight) - >> (WMULT_SHIFT/2); - } else { - tmp = (tmp * lw->inv_weight) >> WMULT_SHIFT; - } + if (unlikely(tmp > WMULT_CONST)) + tmp = RSR(RSR(tmp, WMULT_SHIFT/2) * lw->inv_weight, + WMULT_SHIFT/2); + else + tmp = RSR(tmp * lw->inv_weight, WMULT_SHIFT); return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); } |