As Srikar pointed out (https://lkml.org/lkml/2015/3/27/26):
| With the current code when the ilb cpus are not free: | - We would be updating the nohz.next_balance even through we havent done | any load balance. | - We might iterate thro the nohz.idle_cpus_mask()s to find balance_cpus. This patch fix it by adding need_resched check with the idle check, and keep the need_resched check in for loop to catch ilb get busy. Suggested-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com> Signed-off-by: Wanpeng Li <wanpeng...@linux.intel.com> --- kernel/sched/fair.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0576ce0..1d3e17f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7639,7 +7639,8 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) int balance_cpu; if (idle != CPU_IDLE || - !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) + !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)) || + need_resched()) goto end; for_each_cpu(balance_cpu, nohz.idle_cpus_mask) { -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/