On Fri, Mar 27, 2015 at 12:58:22AM -0700, Jason Low wrote: >On Fri, 2015-03-27 at 15:25 +0800, Wanpeng Li wrote: >> 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; > >How about having: > > if (idle != CPU_IDLE || need_resched() || > !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) > >which wouldn't require adding a new line.
Will do. > >Besides that: > >Reviewed-by: Jason Low <jason.l...@hp.com> Thanks, ;) Regards, Wanpeng Li -- 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/