[PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

[PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

[Li Zefan]

The #if/#endif is ugly. Let SCHED_CPUMASK_ALLOC do kmalloc().

Also remove unnecessary pointer casting.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/sched.c |   21 ++++++++++-----------
 1 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index e8819bc..dee79ad 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7318,13 +7318,13 @@ struct allmasks {
 };
 
 #if	NR_CPUS > 128
-#define	SCHED_CPUMASK_ALLOC		1
-#define	SCHED_CPUMASK_FREE(v)		kfree(v)
-#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
+#define SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
+#define SCHED_CPUMASK_ALLOC(v)		v = kmalloc(sizeof(*v), GFP_KERNEL)
+#define SCHED_CPUMASK_FREE(v)		kfree(v)
 #else
-#define	SCHED_CPUMASK_ALLOC		0
-#define	SCHED_CPUMASK_FREE(v)
-#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
+#define SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
+#define SCHED_CPUMASK_ALLOC(v)
+#define SCHED_CPUMASK_FREE(v)
 #endif
 
 #define	SCHED_CPUMASK_VAR(v, a) 	cpumask_t *v = (cpumask_t *) \
@@ -7400,9 +7400,8 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 		return -ENOMEM;
 	}
 
-#if SCHED_CPUMASK_ALLOC
 	/* get space for all scratch cpumask variables */
-	allmasks = kmalloc(sizeof(*allmasks), GFP_KERNEL);
+	SCHED_CPUMASK_ALLOC(allmasks);
 	if (!allmasks) {
 		printk(KERN_WARNING "Cannot alloc cpumask array\n");
 		kfree(rd);
@@ -7411,7 +7410,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 #endif
 		return -ENOMEM;
 	}
-#endif
+
 	tmpmask = (cpumask_t *)allmasks;
 
 
@@ -7665,13 +7664,13 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 		cpu_attach_domain(sd, rd, i);
 	}
 
-	SCHED_CPUMASK_FREE((void *)allmasks);
+	SCHED_CPUMASK_FREE(allmasks);
 	return 0;
 
 #ifdef CONFIG_NUMA
 error:
 	free_sched_groups(cpu_map, tmpmask);
-	SCHED_CPUMASK_FREE((void *)allmasks);
+	SCHED_CPUMASK_FREE(allmasks);
 	return -ENOMEM;
 #endif
 }
-- 
1.5.4.rc3

Re: [PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

[Ingo Molnar]

* Li Zefan <lizf@cn.fujitsu.com> wrote:

>  #if	NR_CPUS > 128
> -#define	SCHED_CPUMASK_ALLOC		1
> -#define	SCHED_CPUMASK_FREE(v)		kfree(v)
> -#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
> +#define SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
> +#define SCHED_CPUMASK_ALLOC(v)		v = kmalloc(sizeof(*v), GFP_KERNEL)
> +#define SCHED_CPUMASK_FREE(v)		kfree(v)
>  #else
> -#define	SCHED_CPUMASK_ALLOC		0
> -#define	SCHED_CPUMASK_FREE(v)
> -#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
> +#define SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
> +#define SCHED_CPUMASK_ALLOC(v)
> +#define SCHED_CPUMASK_FREE(v)
>  #endif

ok, the #ifdef removal is nice, but we can make it even cleaner: 
please just change it to a sched_cpumask_alloc() inline. That way 
SCHED_CPUMASK_DECLARE() can go away as well: just declare the 
variable, it will be unused in the <128 CPUs case.

	Ingo

Re: [PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

[Li Zefan]

>>  #if	NR_CPUS > 128
>> -#define	SCHED_CPUMASK_ALLOC		1
>> -#define	SCHED_CPUMASK_FREE(v)		kfree(v)
>> -#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
>> +#define SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
>> +#define SCHED_CPUMASK_ALLOC(v)		v = kmalloc(sizeof(*v), GFP_KERNEL)
>> +#define SCHED_CPUMASK_FREE(v)		kfree(v)
>>  #else
>> -#define	SCHED_CPUMASK_ALLOC		0
>> -#define	SCHED_CPUMASK_FREE(v)
>> -#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
>> +#define SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
>> +#define SCHED_CPUMASK_ALLOC(v)
>> +#define SCHED_CPUMASK_FREE(v)
>>  #endif
> 
> ok, the #ifdef removal is nice, but we can make it even cleaner: 
> please just change it to a sched_cpumask_alloc() inline. That way 
> SCHED_CPUMASK_DECLARE() can go away as well: just declare the 
> variable, it will be unused in the <128 CPUs case.
> 

I don't catch you. :(

In the <128 CPUs case, SCHED_CPUMASK_DECLARE is needed to declare a local
variable(struct allmasks) and a pointer pointing to it. So I don't know
what you mean by 'unused' and how to remove the DECLARE macro..

Re: [PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

[Ingo Molnar]

* Li Zefan <lizf@cn.fujitsu.com> wrote:

> >>  #if	NR_CPUS > 128
> >> -#define	SCHED_CPUMASK_ALLOC		1
> >> -#define	SCHED_CPUMASK_FREE(v)		kfree(v)
> >> -#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
> >> +#define SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
> >> +#define SCHED_CPUMASK_ALLOC(v)		v = kmalloc(sizeof(*v), GFP_KERNEL)
> >> +#define SCHED_CPUMASK_FREE(v)		kfree(v)
> >>  #else
> >> -#define	SCHED_CPUMASK_ALLOC		0
> >> -#define	SCHED_CPUMASK_FREE(v)
> >> -#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
> >> +#define SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
> >> +#define SCHED_CPUMASK_ALLOC(v)
> >> +#define SCHED_CPUMASK_FREE(v)
> >>  #endif
> > 
> > ok, the #ifdef removal is nice, but we can make it even cleaner: 
> > please just change it to a sched_cpumask_alloc() inline. That way 
> > SCHED_CPUMASK_DECLARE() can go away as well: just declare the 
> > variable, it will be unused in the <128 CPUs case.
> > 
> 
> I don't catch you. :(
> 
> In the <128 CPUs case, SCHED_CPUMASK_DECLARE is needed to declare a 
> local variable(struct allmasks) and a pointer pointing to it. So I 
> don't know what you mean by 'unused' and how to remove the DECLARE 
> macro..

Sorry, you are right - keep the SCHED_CPUMASK_DECLARE() macro please. 

But the other macros can become an inline function just fine, correct?

	Ingo

Re: [PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

[Li Zefan]

 Sorry, you are right - keep the SCHED_CPUMASK_DECLARE() macro please. 
> 
> But the other macros can become an inline function just fine, correct?
> 

Yes, but sched_cpumask_alloc() should be declared this way:
	void sched_cpumask_alloc(struct **allmasks)
but not:
	struct *allmasks sched_cpumask_alloc(void)

Because the latter is not workable for <128 CPUs case.

(patch is based on [PATCH] sched: fix memory leak in a failing path)

==============

From: Li Zefan <lizf@cn.fujitsu.com>
Date: Fri, 7 Nov 2008 16:49:47 +0800
Subject: [PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

The #if/#endif is ugly. Change SCHED_CPUMASK_ALLOC and
SCHED_CPUMASK_FREE to static inline functions.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/sched.c |   29 ++++++++++++++++++-----------
 1 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 24a70d5..fe4f15e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7318,13 +7318,21 @@ struct allmasks {
 };
 
 #if	NR_CPUS > 128
-#define	SCHED_CPUMASK_ALLOC		1
-#define	SCHED_CPUMASK_FREE(v)		kfree(v)
-#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
+#define SCHED_CPUMASK_DECLARE(v)	struct allmasks *v
+static inline void sched_cpumask_alloc(struct allmasks **masks)
+{
+	*masks = kmalloc(sizeof(**masks), GFP_KERNEL);
+}
+static inline void sched_cpumask_free(struct allmasks *masks)
+{
+	kfree(masks);
+}
 #else
-#define	SCHED_CPUMASK_ALLOC		0
-#define	SCHED_CPUMASK_FREE(v)
-#define	SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
+#define SCHED_CPUMASK_DECLARE(v)	struct allmasks _v, *v = &_v
+static inline void sched_cpumask_alloc(struct allmasks **masks)
+{ }
+static inline void sched_cpumask_free(struct allmasks *masks)
+{ }
 #endif
 
 #define	SCHED_CPUMASK_VAR(v, a) 	cpumask_t *v = (cpumask_t *) \
@@ -7400,9 +7408,8 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 		return -ENOMEM;
 	}
 
-#if SCHED_CPUMASK_ALLOC
 	/* get space for all scratch cpumask variables */
-	allmasks = kmalloc(sizeof(*allmasks), GFP_KERNEL);
+	sched_cpumask_alloc(&allmasks);
 	if (!allmasks) {
 		printk(KERN_WARNING "Cannot alloc cpumask array\n");
 		kfree(rd);
@@ -7411,7 +7418,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 #endif
 		return -ENOMEM;
 	}
-#endif
+
 	tmpmask = (cpumask_t *)allmasks;
 
 
@@ -7665,13 +7672,13 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 		cpu_attach_domain(sd, rd, i);
 	}
 
-	SCHED_CPUMASK_FREE((void *)allmasks);
+	sched_cpumask_free(allmasks);
 	return 0;
 
 #ifdef CONFIG_NUMA
 error:
 	free_sched_groups(cpu_map, tmpmask);
-	SCHED_CPUMASK_FREE((void *)allmasks);
+	sched_cpumask_free(allmasks);
 	kfree(rd);
 	return -ENOMEM;
 #endif
-- 
1.5.4.rc3

Re: [PATCH] sched: rewrite SCHED_CPUMASK_ALLOC

[Ingo Molnar]

* Li Zefan <lizf@cn.fujitsu.com> wrote:

>  Sorry, you are right - keep the SCHED_CPUMASK_DECLARE() macro please. 
> > 
> > But the other macros can become an inline function just fine, correct?
> > 
> 
> Yes, but sched_cpumask_alloc() should be declared this way:
> 	void sched_cpumask_alloc(struct **allmasks)
> but not:
> 	struct *allmasks sched_cpumask_alloc(void)
> 
> Because the latter is not workable for <128 CPUs case.
> 
> (patch is based on [PATCH] sched: fix memory leak in a failing path)

applied to tip/sched/core, thanks!

	Ingo