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Subject[rfc 32/45] Module handling: Use CPU_xx ops to dynamically allocate counters
Use the CPU_xx operations to deal with the per cpu data.

Avoid a loop to NR_CPUS here. Use the possible map instead.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
include/linux/module.h | 13 +++++--------
kernel/module.c | 17 +++++++----------
2 files changed, 12 insertions(+), 18 deletions(-)
Index: linux-2.6/include/linux/module.h
===================================================================
--- linux-2.6.orig/include/linux/module.h 2007-11-19 14:44:06.233923291 -0800
+++ linux-2.6/include/linux/module.h 2007-11-19 15:10:50.982356094 -0800
@@ -219,8 +219,8 @@ void *__symbol_get_gpl(const char *symbo

struct module_ref
{
- local_t count;
-} ____cacheline_aligned;
+ int count;
+};

enum module_state
{
@@ -324,7 +324,7 @@ struct module

#ifdef CONFIG_MODULE_UNLOAD
/* Reference counts */
- struct module_ref ref[NR_CPUS];
+ struct module_ref *ref;

/* What modules depend on me? */
struct list_head modules_which_use_me;
@@ -401,8 +401,7 @@ static inline void __module_get(struct m
{
if (module) {
BUG_ON(module_refcount(module) == 0);
- local_inc(&module->ref[get_cpu()].count);
- put_cpu();
+ _CPU_INC(module->ref->count);
}
}

@@ -411,12 +410,10 @@ static inline int try_module_get(struct
int ret = 1;

if (module) {
- unsigned int cpu = get_cpu();
if (likely(module_is_live(module)))
- local_inc(&module->ref[cpu].count);
+ _CPU_INC(module->ref->count);
else
ret = 0;
- put_cpu();
}
return ret;
}
Index: linux-2.6/kernel/module.c
===================================================================
--- linux-2.6.orig/kernel/module.c 2007-11-19 14:44:06.241923622 -0800
+++ linux-2.6/kernel/module.c 2007-11-19 15:20:28.491897584 -0800
@@ -501,13 +501,11 @@ MODINFO_ATTR(srcversion);
/* Init the unload section of the module. */
static void module_unload_init(struct module *mod)
{
- unsigned int i;
-
INIT_LIST_HEAD(&mod->modules_which_use_me);
- for (i = 0; i < NR_CPUS; i++)
- local_set(&mod->ref[i].count, 0);
+ mod->ref = CPU_ALLOC(struct module_ref, GFP_KERNEL | __GFP_ZERO);
+
/* Hold reference count during initialization. */
- local_set(&mod->ref[raw_smp_processor_id()].count, 1);
+ __CPU_WRITE(mod->ref->count, 1);
/* Backwards compatibility macros put refcount during init. */
mod->waiter = current;
}
@@ -575,6 +573,7 @@ static void module_unload_free(struct mo
kfree(use);
sysfs_remove_link(i->holders_dir, mod->name);
/* There can be at most one match. */
+ CPU_FREE(i->ref);
break;
}
}
@@ -630,8 +629,8 @@ unsigned int module_refcount(struct modu
{
unsigned int i, total = 0;

- for (i = 0; i < NR_CPUS; i++)
- total += local_read(&mod->ref[i].count);
+ for_each_online_cpu(i)
+ total += CPU_PTR(mod->ref, i)->count;
return total;
}
EXPORT_SYMBOL(module_refcount);
@@ -790,12 +789,10 @@ static struct module_attribute refcnt =
void module_put(struct module *module)
{
if (module) {
- unsigned int cpu = get_cpu();
- local_dec(&module->ref[cpu].count);
+ _CPU_DEC(module->ref->count);
/* Maybe they're waiting for us to drop reference? */
if (unlikely(!module_is_live(module)))
wake_up_process(module->waiter);
- put_cpu();
}
}
EXPORT_SYMBOL(module_put);
--
-
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