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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2012-01-13 09:32:14 +1030 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2012-01-13 09:32:14 +1030 |
| commit | bd77c04772da38fca510c81f78e51f727123b919 (patch) | |
| tree | 8554b40191d3d5adebbd2461d26450c0ed7295d4 /include/linux/module.h | |
| parent | 48fd11880b5ef04270be8a87d9a9a9ee2fdae338 (diff) | |
| download | lwn-bd77c04772da38fca510c81f78e51f727123b919.tar.gz lwn-bd77c04772da38fca510c81f78e51f727123b919.zip | |
module: struct module_ref should contains long fields
module_ref contains two "unsigned int" fields.
Thats now too small, since some machines can open more than 2^32 files.
Check commit 518de9b39e8 (fs: allow for more than 2^31 files) for
reference.
We can add an aligned(2 * sizeof(unsigned long)) attribute to force
alloc_percpu() allocating module_ref areas in single cache lines.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Tejun Heo <tj@kernel.org>
CC: Robin Holt <holt@sgi.com>
CC: David Miller <davem@davemloft.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'include/linux/module.h')
| -rw-r--r-- | include/linux/module.h | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/include/linux/module.h b/include/linux/module.h index 3cb7839a60b9..4598bf03e98b 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -205,6 +205,20 @@ enum module_state MODULE_STATE_GOING, }; +/** + * struct module_ref - per cpu module reference counts + * @incs: number of module get on this cpu + * @decs: number of module put on this cpu + * + * We force an alignment on 8 or 16 bytes, so that alloc_percpu() + * put @incs/@decs in same cache line, with no extra memory cost, + * since alloc_percpu() is fine grained. + */ +struct module_ref { + unsigned long incs; + unsigned long decs; +} __attribute((aligned(2 * sizeof(unsigned long)))); + struct module { enum module_state state; @@ -347,10 +361,7 @@ struct module /* Destruction function. */ void (*exit)(void); - struct module_ref { - unsigned int incs; - unsigned int decs; - } __percpu *refptr; + struct module_ref __percpu *refptr; #endif #ifdef CONFIG_CONSTRUCTORS @@ -434,7 +445,7 @@ extern void __module_put_and_exit(struct module *mod, long code) #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code); #ifdef CONFIG_MODULE_UNLOAD -unsigned int module_refcount(struct module *mod); +unsigned long module_refcount(struct module *mod); void __symbol_put(const char *symbol); #define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x) void symbol_put_addr(void *addr); |