Messages in this thread Patch in this message | | | From | Wanpeng Li <> | Subject | [PATCH] sched/fair: fix update the nohz.next_balance even if we haven't done any load balance | Date | Fri, 27 Mar 2015 15:25:00 +0800 |
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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 <srikar@linux.vnet.ibm.com> Signed-off-by: Wanpeng Li <wanpeng.li@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
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