diff options
author | Ingo Molnar <mingo@elte.hu> | 2012-02-24 07:31:31 (GMT) |
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committer | Ingo Molnar <mingo@elte.hu> | 2012-02-24 09:05:59 (GMT) |
commit | c5905afb0ee6550b42c49213da1c22d67316c194 (patch) | |
tree | 253fdb322e6e5b257ffda3b9b66bce90a473a6f7 /include/net/sock.h | |
parent | 1cfa60dc7d7c7cc774a44eee47ff135a644a1f31 (diff) | |
download | linux-c5905afb0ee6550b42c49213da1c22d67316c194.tar.xz |
static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]()
So here's a boot tested patch on top of Jason's series that does
all the cleanups I talked about and turns jump labels into a
more intuitive to use facility. It should also address the
various misconceptions and confusions that surround jump labels.
Typical usage scenarios:
#include <linux/static_key.h>
struct static_key key = STATIC_KEY_INIT_TRUE;
if (static_key_false(&key))
do unlikely code
else
do likely code
Or:
if (static_key_true(&key))
do likely code
else
do unlikely code
The static key is modified via:
static_key_slow_inc(&key);
...
static_key_slow_dec(&key);
The 'slow' prefix makes it abundantly clear that this is an
expensive operation.
I've updated all in-kernel code to use this everywhere. Note
that I (intentionally) have not pushed through the rename
blindly through to the lowest levels: the actual jump-label
patching arch facility should be named like that, so we want to
decouple jump labels from the static-key facility a bit.
On non-jump-label enabled architectures static keys default to
likely()/unlikely() branches.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jason Baron <jbaron@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: a.p.zijlstra@chello.nl
Cc: mathieu.desnoyers@efficios.com
Cc: davem@davemloft.net
Cc: ddaney.cavm@gmail.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/net/sock.h')
-rw-r--r-- | include/net/sock.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 91c1c8b..dcde2d9 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -55,7 +55,7 @@ #include <linux/uaccess.h> #include <linux/memcontrol.h> #include <linux/res_counter.h> -#include <linux/jump_label.h> +#include <linux/static_key.h> #include <linux/filter.h> #include <linux/rculist_nulls.h> @@ -924,13 +924,13 @@ inline void sk_refcnt_debug_release(const struct sock *sk) #endif /* SOCK_REFCNT_DEBUG */ #if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_NET) -extern struct jump_label_key memcg_socket_limit_enabled; +extern struct static_key memcg_socket_limit_enabled; static inline struct cg_proto *parent_cg_proto(struct proto *proto, struct cg_proto *cg_proto) { return proto->proto_cgroup(parent_mem_cgroup(cg_proto->memcg)); } -#define mem_cgroup_sockets_enabled static_branch(&memcg_socket_limit_enabled) +#define mem_cgroup_sockets_enabled static_key_false(&memcg_socket_limit_enabled) #else #define mem_cgroup_sockets_enabled 0 static inline struct cg_proto *parent_cg_proto(struct proto *proto, |