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Subject[patch 3/3] x86: cache_info: Kill the atomic allocation in amd_init_l3_cache()
It's not a good reason to allocate memory in the smp function call
just because someone thought it's the most conveniant place.

The AMD L3 data is coupled to the northbridge info by a pointer to the
corresponding north bridge data. So allocating it with the northbridge
data and referencing the northbridge in the cache_info code instead
uses less memory and gets rid of that atomic allocation hack in the
smp function call.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/amd_nb.h | 6 ++
arch/x86/kernel/cpu/intel_cacheinfo.c | 74 +++++++++++-----------------------
2 files changed, 32 insertions(+), 48 deletions(-)

Index: linux-2.6/arch/x86/include/asm/amd_nb.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/amd_nb.h
+++ linux-2.6/arch/x86/include/asm/amd_nb.h
@@ -19,9 +19,15 @@ extern int amd_numa_init(void);
extern int amd_get_subcaches(int);
extern int amd_set_subcaches(int, int);

+struct amd_l3_cache {
+ unsigned indices;
+ u8 subcaches[4];
+};
+
struct amd_northbridge {
struct pci_dev *misc;
struct pci_dev *link;
+ struct amd_l3_cache l3_cache;
};

struct amd_northbridge_info {
Index: linux-2.6/arch/x86/kernel/cpu/intel_cacheinfo.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ linux-2.6/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -151,18 +151,12 @@ union _cpuid4_leaf_ecx {
u32 full;
};

-struct amd_l3_cache {
- struct amd_northbridge *nb;
- unsigned indices;
- u8 subcaches[4];
-};
-
struct _cpuid4_info_regs {
union _cpuid4_leaf_eax eax;
union _cpuid4_leaf_ebx ebx;
union _cpuid4_leaf_ecx ecx;
unsigned long size;
- struct amd_l3_cache *l3;
+ struct amd_northbridge *nb;
};

struct _cpuid4_info {
@@ -309,12 +303,13 @@ struct _cache_attr {
/*
* L3 cache descriptors
*/
-static void __cpuinit amd_calc_l3_indices(struct amd_l3_cache *l3)
+static void __cpuinit amd_calc_l3_indices(struct amd_northbridge *nb)
{
+ struct amd_l3_cache *l3 = &nb->l3_cache;
unsigned int sc0, sc1, sc2, sc3;
u32 val = 0;

- pci_read_config_dword(l3->nb->misc, 0x1C4, &val);
+ pci_read_config_dword(nb->misc, 0x1C4, &val);

/* calculate subcache sizes */
l3->subcaches[0] = sc0 = !(val & BIT(0));
@@ -328,33 +323,16 @@ static void __cpuinit amd_calc_l3_indice
static void __cpuinit amd_init_l3_cache(struct _cpuid4_info_regs *this_leaf,
int index)
{
- static struct amd_l3_cache *__cpuinitdata l3_caches;
int node;

/* only for L3, and not in virtualized environments */
- if (index < 3 || amd_nb_num() == 0)
+ if (index < 3)
return;

- /*
- * Strictly speaking, the amount in @size below is leaked since it is
- * never freed but this is done only on shutdown so it doesn't matter.
- */
- if (!l3_caches) {
- int size = amd_nb_num() * sizeof(struct amd_l3_cache);
-
- l3_caches = kzalloc(size, GFP_ATOMIC);
- if (!l3_caches)
- return;
- }
-
node = amd_get_nb_id(smp_processor_id());
-
- if (!l3_caches[node].nb) {
- l3_caches[node].nb = node_to_amd_nb(node);
- amd_calc_l3_indices(&l3_caches[node]);
- }
-
- this_leaf->l3 = &l3_caches[node];
+ this_leaf->nb = node_to_amd_nb(node);
+ if (this_leaf->nb && !this_leaf->nb->l3_cache.indices)
+ amd_calc_l3_indices(this_leaf->nb);
}

/*
@@ -364,11 +342,11 @@ static void __cpuinit amd_init_l3_cache(
*
* @returns: the disabled index if used or negative value if slot free.
*/
-int amd_get_l3_disable_slot(struct amd_l3_cache *l3, unsigned slot)
+int amd_get_l3_disable_slot(struct amd_northbridge *nb, unsigned slot)
{
unsigned int reg = 0;

- pci_read_config_dword(l3->nb->misc, 0x1BC + slot * 4, &reg);
+ pci_read_config_dword(nb->misc, 0x1BC + slot * 4, &reg);

/* check whether this slot is activated already */
if (reg & (3UL << 30))
@@ -382,10 +360,10 @@ static ssize_t show_cache_disable(struct
{
int index;

- if (!this_leaf->base.l3 || !amd_nb_has_feature(AMD_NB_L3_INDEX_DISABLE))
+ if (!this_leaf->base.nb || !amd_nb_has_feature(AMD_NB_L3_INDEX_DISABLE))
return -EINVAL;

- index = amd_get_l3_disable_slot(this_leaf->base.l3, slot);
+ index = amd_get_l3_disable_slot(this_leaf->base.nb, slot);
if (index >= 0)
return sprintf(buf, "%d\n", index);

@@ -402,7 +380,7 @@ show_cache_disable_##slot(struct _cpuid4
SHOW_CACHE_DISABLE(0)
SHOW_CACHE_DISABLE(1)

-static void amd_l3_disable_index(struct amd_l3_cache *l3, int cpu,
+static void amd_l3_disable_index(struct amd_northbridge *nb, int cpu,
unsigned slot, unsigned long idx)
{
int i;
@@ -415,10 +393,10 @@ static void amd_l3_disable_index(struct
for (i = 0; i < 4; i++) {
u32 reg = idx | (i << 20);

- if (!l3->subcaches[i])
+ if (!nb->l3_cache.subcaches[i])
continue;

- pci_write_config_dword(l3->nb->misc, 0x1BC + slot * 4, reg);
+ pci_write_config_dword(nb->misc, 0x1BC + slot * 4, reg);

/*
* We need to WBINVD on a core on the node containing the L3
@@ -428,7 +406,7 @@ static void amd_l3_disable_index(struct
wbinvd_on_cpu(cpu);

reg |= BIT(31);
- pci_write_config_dword(l3->nb->misc, 0x1BC + slot * 4, reg);
+ pci_write_config_dword(nb->misc, 0x1BC + slot * 4, reg);
}
}

@@ -442,24 +420,24 @@ static void amd_l3_disable_index(struct
*
* @return: 0 on success, error status on failure
*/
-int amd_set_l3_disable_slot(struct amd_l3_cache *l3, int cpu, unsigned slot,
+int amd_set_l3_disable_slot(struct amd_northbridge *nb, int cpu, unsigned slot,
unsigned long index)
{
int ret = 0;

/* check if @slot is already used or the index is already disabled */
- ret = amd_get_l3_disable_slot(l3, slot);
+ ret = amd_get_l3_disable_slot(nb, slot);
if (ret >= 0)
return -EINVAL;

- if (index > l3->indices)
+ if (index > nb->l3_cache.indices)
return -EINVAL;

/* check whether the other slot has disabled the same index already */
- if (index == amd_get_l3_disable_slot(l3, !slot))
+ if (index == amd_get_l3_disable_slot(nb, !slot))
return -EINVAL;

- amd_l3_disable_index(l3, cpu, slot, index);
+ amd_l3_disable_index(nb, cpu, slot, index);

return 0;
}
@@ -474,7 +452,7 @@ static ssize_t store_cache_disable(struc
if (!capable(CAP_SYS_ADMIN))
return -EPERM;

- if (!this_leaf->base.l3 || !amd_nb_has_feature(AMD_NB_L3_INDEX_DISABLE))
+ if (!this_leaf->base.nb || !amd_nb_has_feature(AMD_NB_L3_INDEX_DISABLE))
return -EINVAL;

cpu = cpumask_first(to_cpumask(this_leaf->shared_cpu_map));
@@ -482,7 +460,7 @@ static ssize_t store_cache_disable(struc
if (strict_strtoul(buf, 10, &val) < 0)
return -EINVAL;

- err = amd_set_l3_disable_slot(this_leaf->base.l3, cpu, slot, val);
+ err = amd_set_l3_disable_slot(this_leaf->base.nb, cpu, slot, val);
if (err) {
if (err == -EEXIST)
printk(KERN_WARNING "L3 disable slot %d in use!\n",
@@ -511,7 +489,7 @@ static struct _cache_attr cache_disable_
static ssize_t
show_subcaches(struct _cpuid4_info *this_leaf, char *buf, unsigned int cpu)
{
- if (!this_leaf->base.l3 || !amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
+ if (!this_leaf->base.nb || !amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
return -EINVAL;

return sprintf(buf, "%x\n", amd_get_subcaches(cpu));
@@ -526,7 +504,7 @@ store_subcaches(struct _cpuid4_info *thi
if (!capable(CAP_SYS_ADMIN))
return -EPERM;

- if (!this_leaf->base.l3 || !amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
+ if (!this_leaf->base.nb || !amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
return -EINVAL;

if (strict_strtoul(buf, 16, &val) < 0)
@@ -1118,7 +1096,7 @@ static int __cpuinit cache_add_dev(struc

ktype_cache.default_attrs = default_attrs;
#ifdef CONFIG_AMD_NB
- if (this_leaf->base.l3)
+ if (this_leaf->base.nb)
ktype_cache.default_attrs = amd_l3_attrs();
#endif
retval = kobject_init_and_add(&(this_object->kobj),



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