Re: [RESEND PATCH v11 2/2] sched/rt: Add support for SD_PREFER_SIBLING on find_lowest_rq()

[kbuild test robot]

Hi Byungchul,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tip/sched/core]
[also build test WARNING on v4.15-rc7 next-20180110]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Byungchul-Park/sched-deadline-Add-support-for-SD_PREFER_SIBLING-on-find_later_rq/20180110-225946
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

   kernel/sched/sched.h:2104:16: sparse: incompatible types in comparison expression (different address spaces)
   kernel/sched/rt.c:1681:9: sparse: incompatible types in comparison expression (different address spaces)
>> kernel/sched/rt.c:1629:55: sparse: incorrect type in argument 1 (different modifiers) @@ expected struct sched_domain @@ got structstruct sched_domain @@
   kernel/sched/rt.c:1629:55: expected struct sched_domain
   kernel/sched/rt.c:1629:55: got struct sched_domain const
   kernel/sched/rt.c:1630:64: sparse: incorrect type in argument 1 (different modifiers) @@ expected struct sched_domain @@ got structstruct sched_domain @@
   kernel/sched/rt.c:1630:64: expected struct sched_domain
   kernel/sched/rt.c:1630:64: got struct sched_domain const
   kernel/sched/rt.c:1824:9: sparse: context imbalance in 'find_lock_lowest_rq' - different lock contexts for basic block
   kernel/sched/rt.c:1919:9: sparse: context imbalance in 'push_rt_task' - unexpected unlock
   kernel/sched/rt.c: In function 'find_cpu':
   kernel/sched/rt.c:1629:48: warning: passing argument 1 of 'sched_domain_span' discards 'const' qualifier from pointer target type
    const struct cpumask = sched_domain_span(sd);
    ^~
   In file included from kernel/sched/sched.h:6:0,
    from kernel/sched/rt.c:7:
   include/linux/sched/topology.h:160:31: note: expected 'struct sched_domain but argument is of type 'const struct sched_domain
    static inline struct cpumask sched_domain
    ^~~~~~~~~~~~~~~~~
   kernel/sched/rt.c:1630:57: warning: passing argument 1 of 'sched_domain_span' discards 'const' qualifier from pointer target type
    const struct cpumask = prefer sched_domain_span(prefer) : NULL;
    ^~~~~~
   In file included from kernel/sched/sched.h:6:0,
    from kernel/sched/rt.c:7:
   include/linux/sched/topology.h:160:31: note: expected 'struct sched_domain but argument is of type 'const struct sched_domain
    static inline struct cpumask sched_domain
    ^~~~~~~~~~~~~~~~~

vim +1629 kernel/sched/rt.c

  1621	
  1622	/*
  1623	 * Find the first cpu in: mask & sd & ~prefer
  1624	 */
  1625	static int find_cpu(const struct cpumask *mask,
  1626			    const struct sched_domain *sd,
  1627			    const struct sched_domain *prefer)
  1628	{
> 1629		const struct cpumask *sds = sched_domain_span(sd);
  1630		const struct cpumask *ps  = prefer ? sched_domain_span(prefer) : NULL;
  1631		int cpu;
  1632	
  1633		for_each_cpu(cpu, mask) {
  1634			if (!cpumask_test_cpu(cpu, sds))
  1635				continue;
  1636			if (ps && cpumask_test_cpu(cpu, ps))
  1637				continue;
  1638			break;
  1639		}
  1640	
  1641		return cpu;
  1642	}
  1643	

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