linux-kernel - Re: [PATCH 5/5] x86: Remove #ifdef CONFIG_SMP sections by moving smp_num

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Message-ID: <CAELBVzBTrYoRq9r9+dZFBp6_yXuPQPChCWksXZ1u2ft9w1Q-0A@mail.gmail.com>
Date:	Tue, 21 Feb 2012 21:44:25 -0400
From:	Kevin Winchester <kjwinchester@...il.com>
To:	Borislav Petkov <bp@...en8.de>,
	Kevin Winchester <kjwinchester@...il.com>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Randy Dunlap <rdunlap@...otime.net>,
	Nick Bowler <nbowler@...iptictech.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/5] x86: Remove #ifdef CONFIG_SMP sections by moving
 smp_num_siblings into common.c

On 21 February 2012 11:39, Borislav Petkov <bp@...en8.de> wrote:
> On Mon, Feb 20, 2012 at 10:06:06PM -0400, Kevin Winchester wrote:
>> smp_num_siblings was defined in arch/x86/kernel/smpboot.c, making it
>> necessary to wrap any UP relevant code referencing it with #ifdef
>> CONFIG_SMP.
>>
>> Instead, move the definition to arch/x86/kernel/cpu/common.c, thus
>> making it available always.
>>
>> Signed-off-by: Kevin Winchester <kjwinchester@...il.com>
>> ---
>>  arch/x86/include/asm/perf_event_p4.h |    9 +++------
>>  arch/x86/include/asm/smp.h           |    6 +-----
>>  arch/x86/include/asm/topology.h      |    4 +---
>>  arch/x86/kernel/cpu/amd.c            |    4 ----
>>  arch/x86/kernel/cpu/common.c         |    6 ++++--
>>  arch/x86/kernel/cpu/proc.c           |    5 ++---
>>  arch/x86/kernel/cpu/topology.c       |    2 --
>>  arch/x86/kernel/process.c            |    3 +--
>>  arch/x86/kernel/smpboot.c            |    4 ----
>>  arch/x86/oprofile/nmi_int.c          |    6 ------
>>  arch/x86/oprofile/op_model_p4.c      |    6 ------
>>  11 files changed, 12 insertions(+), 43 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/perf_event_p4.h b/arch/x86/include/asm/perf_event_p4.h
>> index 29a65c2..0d50f33 100644
>> --- a/arch/x86/include/asm/perf_event_p4.h
>> +++ b/arch/x86/include/asm/perf_event_p4.h
>> @@ -8,6 +8,8 @@
>>  #include <linux/cpu.h>
>>  #include <linux/bitops.h>
>>
>> +#include <asm/smp.h>
>> +
>>  /*
>>   * NetBurst has performance MSRs shared between
>>   * threads if HT is turned on, ie for both logical
>> @@ -179,18 +181,13 @@ static inline u64 p4_clear_ht_bit(u64 config)
>>
>>  static inline int p4_ht_active(void)
>>  {
>> -#ifdef CONFIG_SMP
>>       return smp_num_siblings > 1;
>> -#endif
>> -     return 0;
>>  }
>
> You could drop this function completely now and use the equal
> smt_capable() macro below.
>
>>
>>  static inline int p4_ht_thread(int cpu)
>>  {
>> -#ifdef CONFIG_SMP
>>       if (smp_num_siblings == 2)
>> -             return cpu != cpumask_first(&cpu_data(cpu).sibling_map));
>> -#endif
>> +             return cpu != cpumask_first(&cpu_data(cpu).sibling_map);
>>       return 0;
>>  }
>>
>> diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
>> index 75aea4d..787127e 100644
>> --- a/arch/x86/include/asm/smp.h
>> +++ b/arch/x86/include/asm/smp.h
>> @@ -24,11 +24,7 @@ extern unsigned int num_processors;
>>
>>  static inline bool cpu_has_ht_siblings(void)
>>  {
>> -     bool has_siblings = false;
>> -#ifdef CONFIG_SMP
>> -     has_siblings = cpu_has_ht && smp_num_siblings > 1;
>> -#endif
>> -     return has_siblings;
>> +     return cpu_has_ht && smp_num_siblings > 1;
>>  }
>>
>>  DECLARE_PER_CPU(int, cpu_number);
>> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
>> index 58438a1b..7250ad1 100644
>> --- a/arch/x86/include/asm/topology.h
>> +++ b/arch/x86/include/asm/topology.h
>> @@ -174,11 +174,9 @@ static inline void arch_fix_phys_package_id(int num, u32 slot)
>>  struct pci_bus;
>>  void x86_pci_root_bus_resources(int bus, struct list_head *resources);
>>
>> -#ifdef CONFIG_SMP
>>  #define mc_capable() ((boot_cpu_data.x86_max_cores > 1) && \
>>                       (cpumask_weight(&boot_cpu_data.core_map) != nr_cpu_ids))
>> -#define smt_capable()                        (smp_num_siblings > 1)
>> -#endif
>> +#define smt_capable()        (smp_num_siblings > 1)
>>
>>  #ifdef CONFIG_NUMA
>>  extern int get_mp_bus_to_node(int busnum);
>> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
>> index 1cd9d51..a8b46df 100644
>> --- a/arch/x86/kernel/cpu/amd.c
>> +++ b/arch/x86/kernel/cpu/amd.c
>> @@ -263,7 +263,6 @@ static int __cpuinit nearby_node(int apicid)
>>   *     Assumption: Number of cores in each internal node is the same.
>>   * (2) AMD processors supporting compute units
>>   */
>> -#ifdef CONFIG_X86_HT
>>  static void __cpuinit amd_get_topology(struct cpuinfo_x86 *c)
>>  {
>>       u32 nodes, cores_per_cu = 1;
>> @@ -307,7 +306,6 @@ static void __cpuinit amd_get_topology(struct cpuinfo_x86 *c)
>>               c->compute_unit_id %= cus_per_node;
>>       }
>>  }
>> -#endif
>
> I'm assuming all those X86_HT changes have been built and boot-tested
> also with CONFIG_X86_HT unset?
>

Yes, I am running a !CONFIG_SMP build with these patches applied right now.

New version of the patchset coming in a few minutes with all requested changes.

-- 
Kevin Winchester
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