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Merge branch 'perf/jump-labels' into perf/core

Browse source 
Merge reason: After much naming discussion, there seems to be consensus
              now - queue it up for v3.4.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2012-02-28 19:59:45 +01:00
commit a706d4fc9e
32 changed files with 589 additions and 207 deletions
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286
Documentation/static-keys.txt Normal file
View file

@ -0,0 +1,286 @@
Static Keys
-----------
By: Jason Baron <jbaron@redhat.com>
0) Abstract
Static keys allows the inclusion of seldom used features in
performance-sensitive fast-path kernel code, via a GCC feature and a code
patching technique. A quick example:
struct static_key key = STATIC_KEY_INIT_FALSE;
...
if (static_key_false(&key))
do unlikely code
else
do likely code
...
static_key_slow_inc();
...
static_key_slow_inc();
...
The static_key_false() branch will be generated into the code with as little
impact to the likely code path as possible.
1) Motivation
Currently, tracepoints are implemented using a conditional branch. The
conditional check requires checking a global variable for each tracepoint.
Although the overhead of this check is small, it increases when the memory
cache comes under pressure (memory cache lines for these global variables may
be shared with other memory accesses). As we increase the number of tracepoints
in the kernel this overhead may become more of an issue. In addition,
tracepoints are often dormant (disabled) and provide no direct kernel
functionality. Thus, it is highly desirable to reduce their impact as much as
possible. Although tracepoints are the original motivation for this work, other
kernel code paths should be able to make use of the static keys facility.
2) Solution
gcc (v4.5) adds a new 'asm goto' statement that allows branching to a label:
http://gcc.gnu.org/ml/gcc-patches/2009-07/msg01556.html
Using the 'asm goto', we can create branches that are either taken or not taken
by default, without the need to check memory. Then, at run-time, we can patch
the branch site to change the branch direction.
For example, if we have a simple branch that is disabled by default:
if (static_key_false(&key))
printk("I am the true branch\n");
Thus, by default the 'printk' will not be emitted. And the code generated will
consist of a single atomic 'no-op' instruction (5 bytes on x86), in the
straight-line code path. When the branch is 'flipped', we will patch the
'no-op' in the straight-line codepath with a 'jump' instruction to the
out-of-line true branch. Thus, changing branch direction is expensive but
branch selection is basically 'free'. That is the basic tradeoff of this
optimization.
This lowlevel patching mechanism is called 'jump label patching', and it gives
the basis for the static keys facility.
3) Static key label API, usage and examples:
In order to make use of this optimization you must first define a key:
struct static_key key;
Which is initialized as:
struct static_key key = STATIC_KEY_INIT_TRUE;
or:
struct static_key key = STATIC_KEY_INIT_FALSE;
If the key is not initialized, it is default false. The 'struct static_key',
must be a 'global'. That is, it can't be allocated on the stack or dynamically
allocated at run-time.
The key is then used in code as:
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
A key that is initialized via 'STATIC_KEY_INIT_FALSE', must be used in a
'static_key_false()' construct. Likewise, a key initialized via
'STATIC_KEY_INIT_TRUE' must be used in a 'static_key_true()' construct. A
single key can be used in many branches, but all the branches must match the
way that the key has been initialized.
The branch(es) can then be switched via:
static_key_slow_inc(&key);
...
static_key_slow_dec(&key);
Thus, 'static_key_slow_inc()' means 'make the branch true', and
'static_key_slow_dec()' means 'make the the branch false' with appropriate
reference counting. For example, if the key is initialized true, a
static_key_slow_dec(), will switch the branch to false. And a subsequent
static_key_slow_inc(), will change the branch back to true. Likewise, if the
key is initialized false, a 'static_key_slow_inc()', will change the branch to
true. And then a 'static_key_slow_dec()', will again make the branch false.
An example usage in the kernel is the implementation of tracepoints:
static inline void trace_##name(proto) \
{ \
if (static_key_false(&__tracepoint_##name.key)) \
__DO_TRACE(&__tracepoint_##name, \
TP_PROTO(data_proto), \
TP_ARGS(data_args), \
TP_CONDITION(cond)); \
}
Tracepoints are disabled by default, and can be placed in performance critical
pieces of the kernel. Thus, by using a static key, the tracepoints can have
absolutely minimal impact when not in use.
4) Architecture level code patching interface, 'jump labels'
There are a few functions and macros that architectures must implement in order
to take advantage of this optimization. If there is no architecture support, we
simply fall back to a traditional, load, test, and jump sequence.
* select HAVE_ARCH_JUMP_LABEL, see: arch/x86/Kconfig
* #define JUMP_LABEL_NOP_SIZE, see: arch/x86/include/asm/jump_label.h
* __always_inline bool arch_static_branch(struct static_key *key), see:
arch/x86/include/asm/jump_label.h
* void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type),
see: arch/x86/kernel/jump_label.c
* __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type),
see: arch/x86/kernel/jump_label.c
* struct jump_entry, see: arch/x86/include/asm/jump_label.h
5) Static keys / jump label analysis, results (x86_64):
As an example, let's add the following branch to 'getppid()', such that the
system call now looks like:
SYSCALL_DEFINE0(getppid)
{
int pid;
+ if (static_key_false(&key))
+ printk("I am the true branch\n");
rcu_read_lock();
pid = task_tgid_vnr(rcu_dereference(current->real_parent));
rcu_read_unlock();
return pid;
}
The resulting instructions with jump labels generated by GCC is:
ffffffff81044290 <sys_getppid>:
ffffffff81044290: 55 push %rbp
ffffffff81044291: 48 89 e5 mov %rsp,%rbp
ffffffff81044294: e9 00 00 00 00 jmpq ffffffff81044299 <sys_getppid+0x9>
ffffffff81044299: 65 48 8b 04 25 c0 b6 mov %gs:0xb6c0,%rax
ffffffff810442a0: 00 00
ffffffff810442a2: 48 8b 80 80 02 00 00 mov 0x280(%rax),%rax
ffffffff810442a9: 48 8b 80 b0 02 00 00 mov 0x2b0(%rax),%rax
ffffffff810442b0: 48 8b b8 e8 02 00 00 mov 0x2e8(%rax),%rdi
ffffffff810442b7: e8 f4 d9 00 00 callq ffffffff81051cb0 <pid_vnr>
ffffffff810442bc: 5d pop %rbp
ffffffff810442bd: 48 98 cltq
ffffffff810442bf: c3 retq
ffffffff810442c0: 48 c7 c7 e3 54 98 81 mov $0xffffffff819854e3,%rdi
ffffffff810442c7: 31 c0 xor %eax,%eax
ffffffff810442c9: e8 71 13 6d 00 callq ffffffff8171563f <printk>
ffffffff810442ce: eb c9 jmp ffffffff81044299 <sys_getppid+0x9>
Without the jump label optimization it looks like:
ffffffff810441f0 <sys_getppid>:
ffffffff810441f0: 8b 05 8a 52 d8 00 mov 0xd8528a(%rip),%eax # ffffffff81dc9480 <key>
ffffffff810441f6: 55 push %rbp
ffffffff810441f7: 48 89 e5 mov %rsp,%rbp
ffffffff810441fa: 85 c0 test %eax,%eax
ffffffff810441fc: 75 27 jne ffffffff81044225 <sys_getppid+0x35>
ffffffff810441fe: 65 48 8b 04 25 c0 b6 mov %gs:0xb6c0,%rax
ffffffff81044205: 00 00
ffffffff81044207: 48 8b 80 80 02 00 00 mov 0x280(%rax),%rax
ffffffff8104420e: 48 8b 80 b0 02 00 00 mov 0x2b0(%rax),%rax
ffffffff81044215: 48 8b b8 e8 02 00 00 mov 0x2e8(%rax),%rdi
ffffffff8104421c: e8 2f da 00 00 callq ffffffff81051c50 <pid_vnr>
ffffffff81044221: 5d pop %rbp
ffffffff81044222: 48 98 cltq
ffffffff81044224: c3 retq
ffffffff81044225: 48 c7 c7 13 53 98 81 mov $0xffffffff81985313,%rdi
ffffffff8104422c: 31 c0 xor %eax,%eax
ffffffff8104422e: e8 60 0f 6d 00 callq ffffffff81715193 <printk>
ffffffff81044233: eb c9 jmp ffffffff810441fe <sys_getppid+0xe>
ffffffff81044235: 66 66 2e 0f 1f 84 00 data32 nopw %cs:0x0(%rax,%rax,1)
ffffffff8104423c: 00 00 00 00
Thus, the disable jump label case adds a 'mov', 'test' and 'jne' instruction
vs. the jump label case just has a 'no-op' or 'jmp 0'. (The jmp 0, is patched
to a 5 byte atomic no-op instruction at boot-time.) Thus, the disabled jump
label case adds:
6 (mov) + 2 (test) + 2 (jne) = 10 - 5 (5 byte jump 0) = 5 addition bytes.
If we then include the padding bytes, the jump label code saves, 16 total bytes
of instruction memory for this small fucntion. In this case the non-jump label
function is 80 bytes long. Thus, we have have saved 20% of the instruction
footprint. We can in fact improve this even further, since the 5-byte no-op
really can be a 2-byte no-op since we can reach the branch with a 2-byte jmp.
However, we have not yet implemented optimal no-op sizes (they are currently
hard-coded).
Since there are a number of static key API uses in the scheduler paths,
'pipe-test' (also known as 'perf bench sched pipe') can be used to show the
performance improvement. Testing done on 3.3.0-rc2:
jump label disabled:
Performance counter stats for 'bash -c /tmp/pipe-test' (50 runs):
855.700314 task-clock # 0.534 CPUs utilized ( +- 0.11% )
200,003 context-switches # 0.234 M/sec ( +- 0.00% )
0 CPU-migrations # 0.000 M/sec ( +- 39.58% )
487 page-faults # 0.001 M/sec ( +- 0.02% )
1,474,374,262 cycles # 1.723 GHz ( +- 0.17% )
<not supported> stalled-cycles-frontend
<not supported> stalled-cycles-backend
1,178,049,567 instructions # 0.80 insns per cycle ( +- 0.06% )
208,368,926 branches # 243.507 M/sec ( +- 0.06% )
5,569,188 branch-misses # 2.67% of all branches ( +- 0.54% )
1.601607384 seconds time elapsed ( +- 0.07% )
jump label enabled:
Performance counter stats for 'bash -c /tmp/pipe-test' (50 runs):
841.043185 task-clock # 0.533 CPUs utilized ( +- 0.12% )
200,004 context-switches # 0.238 M/sec ( +- 0.00% )
0 CPU-migrations # 0.000 M/sec ( +- 40.87% )
487 page-faults # 0.001 M/sec ( +- 0.05% )
1,432,559,428 cycles # 1.703 GHz ( +- 0.18% )
<not supported> stalled-cycles-frontend
<not supported> stalled-cycles-backend
1,175,363,994 instructions # 0.82 insns per cycle ( +- 0.04% )
206,859,359 branches # 245.956 M/sec ( +- 0.04% )
4,884,119 branch-misses # 2.36% of all branches ( +- 0.85% )
1.579384366 seconds time elapsed
The percentage of saved branches is .7%, and we've saved 12% on
'branch-misses'. This is where we would expect to get the most savings, since
this optimization is about reducing the number of branches. In addition, we've
saved .2% on instructions, and 2.8% on cycles and 1.4% on elapsed time.

29
arch/Kconfig
View file

@ -47,18 +47,29 @@ config KPROBES
If in doubt, say "N".
config JUMP_LABEL
bool "Optimize trace point call sites"
bool "Optimize very unlikely/likely branches"
depends on HAVE_ARCH_JUMP_LABEL
help
If it is detected that the compiler has support for "asm goto",
the kernel will compile trace point locations with just a
nop instruction. When trace points are enabled, the nop will
be converted to a jump to the trace function. This technique
lowers overhead and stress on the branch prediction of the
processor.
This option enables a transparent branch optimization that
makes certain almost-always-true or almost-always-false branch
conditions even cheaper to execute within the kernel.
On i386, options added to the compiler flags may increase
the size of the kernel slightly.
Certain performance-sensitive kernel code, such as trace points,
scheduler functionality, networking code and KVM have such
branches and include support for this optimization technique.
If it is detected that the compiler has support for "asm goto",
the kernel will compile such branches with just a nop
instruction. When the condition flag is toggled to true, the
nop will be converted to a jump instruction to execute the
conditional block of instructions.
This technique lowers overhead and stress on the branch prediction
of the processor and generally makes the kernel faster. The update
of the condition is slower, but those are always very rare.
( On 32-bit x86, the necessary options added to the compiler
flags may increase the size of the kernel slightly. )
config OPTPROBES
def_bool y

6
arch/ia64/include/asm/paravirt.h
View file

@ -281,9 +281,9 @@ paravirt_init_missing_ticks_accounting(int cpu)
pv_time_ops.init_missing_ticks_accounting(cpu);
}
struct jump_label_key;
extern struct jump_label_key paravirt_steal_enabled;
extern struct jump_label_key paravirt_steal_rq_enabled;
struct static_key;
extern struct static_key paravirt_steal_enabled;
extern struct static_key paravirt_steal_rq_enabled;
static inline int
paravirt_do_steal_accounting(unsigned long *new_itm)

4
arch/ia64/kernel/paravirt.c
View file

@ -634,8 +634,8 @@ struct pv_irq_ops pv_irq_ops = {
* pv_time_ops
* time operations
*/
struct jump_label_key paravirt_steal_enabled;
struct jump_label_key paravirt_steal_rq_enabled;
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
static int
ia64_native_do_steal_accounting(unsigned long *new_itm)

2
arch/mips/include/asm/jump_label.h
View file

@ -20,7 +20,7 @@
#define WORD_INSN ".word"
#endif
static __always_inline bool arch_static_branch(struct jump_label_key *key)
static __always_inline bool arch_static_branch(struct static_key *key)
{
asm goto("1:\tnop\n\t"
"nop\n\t"

2
arch/powerpc/include/asm/jump_label.h
View file

@ -17,7 +17,7 @@
#define JUMP_ENTRY_TYPE stringify_in_c(FTR_ENTRY_LONG)
#define JUMP_LABEL_NOP_SIZE 4
static __always_inline bool arch_static_branch(struct jump_label_key *key)
static __always_inline bool arch_static_branch(struct static_key *key)
{
asm goto("1:\n\t"
"nop\n\t"

2
arch/s390/include/asm/jump_label.h
View file

@ -13,7 +13,7 @@
#define ASM_ALIGN ".balign 4"
#endif
static __always_inline bool arch_static_branch(struct jump_label_key *key)
static __always_inline bool arch_static_branch(struct static_key *key)
{
asm goto("0: brcl 0,0\n"
".pushsection __jump_table, \"aw\"\n"

2
arch/sparc/include/asm/jump_label.h
View file

@ -7,7 +7,7 @@
#define JUMP_LABEL_NOP_SIZE 4
static __always_inline bool arch_static_branch(struct jump_label_key *key)
static __always_inline bool arch_static_branch(struct static_key *key)
{
asm goto("1:\n\t"
"nop\n\t"

6
arch/x86/include/asm/jump_label.h
View file

@ -9,12 +9,12 @@
#define JUMP_LABEL_NOP_SIZE 5
#define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
#define STATIC_KEY_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
static __always_inline bool arch_static_branch(struct jump_label_key *key)
static __always_inline bool arch_static_branch(struct static_key *key)
{
asm goto("1:"
JUMP_LABEL_INITIAL_NOP
STATIC_KEY_INITIAL_NOP
".pushsection __jump_table, \"aw\" \n\t"
_ASM_ALIGN "\n\t"
_ASM_PTR "1b, %l[l_yes], %c0 \n\t"

6
arch/x86/include/asm/paravirt.h
View file

@ -230,9 +230,9 @@ static inline unsigned long long paravirt_sched_clock(void)
return PVOP_CALL0(unsigned long long, pv_time_ops.sched_clock);
}
struct jump_label_key;
extern struct jump_label_key paravirt_steal_enabled;
extern struct jump_label_key paravirt_steal_rq_enabled;
struct static_key;
extern struct static_key paravirt_steal_enabled;
extern struct static_key paravirt_steal_rq_enabled;
static inline u64 paravirt_steal_clock(int cpu)
{

4
arch/x86/kernel/kvm.c
View file

@ -438,9 +438,9 @@ void __init kvm_guest_init(void)
static __init int activate_jump_labels(void)
{
if (has_steal_clock) {
jump_label_inc(&paravirt_steal_enabled);
static_key_slow_inc(&paravirt_steal_enabled);
if (steal_acc)
jump_label_inc(&paravirt_steal_rq_enabled);
static_key_slow_inc(&paravirt_steal_rq_enabled);
}
return 0;

4
arch/x86/kernel/paravirt.c
View file

@ -202,8 +202,8 @@ static void native_flush_tlb_single(unsigned long addr)
__native_flush_tlb_single(addr);
}
struct jump_label_key paravirt_steal_enabled;
struct jump_label_key paravirt_steal_rq_enabled;
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
static u64 native_steal_clock(int cpu)
{

8
arch/x86/kvm/mmu_audit.c
View file

@ -234,7 +234,7 @@ static void audit_vcpu_spte(struct kvm_vcpu *vcpu)
}
static bool mmu_audit;
static struct jump_label_key mmu_audit_key;
static struct static_key mmu_audit_key;
static void __kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
{
@ -250,7 +250,7 @@ static void __kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
static inline void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point)
{
if (static_branch((&mmu_audit_key)))
if (static_key_false((&mmu_audit_key)))
__kvm_mmu_audit(vcpu, point);
}
@ -259,7 +259,7 @@ static void mmu_audit_enable(void)
if (mmu_audit)
return;
jump_label_inc(&mmu_audit_key);
static_key_slow_inc(&mmu_audit_key);
mmu_audit = true;
}
@ -268,7 +268,7 @@ static void mmu_audit_disable(void)
if (!mmu_audit)
return;
jump_label_dec(&mmu_audit_key);
static_key_slow_dec(&mmu_audit_key);
mmu_audit = false;
}

139
include/linux/jump_label.h
View file

@ -9,15 +9,15 @@
*
* Jump labels provide an interface to generate dynamic branches using
* self-modifying code. Assuming toolchain and architecture support the result
* of a "if (static_branch(&key))" statement is a unconditional branch (which
* of a "if (static_key_false(&key))" statement is a unconditional branch (which
* defaults to false - and the true block is placed out of line).
*
* However at runtime we can change the 'static' branch target using
* jump_label_{inc,dec}(). These function as a 'reference' count on the key
* However at runtime we can change the branch target using
* static_key_slow_{inc,dec}(). These function as a 'reference' count on the key
* object and for as long as there are references all branches referring to
* that particular key will point to the (out of line) true block.
*
* Since this relies on modifying code the jump_label_{inc,dec}() functions
* Since this relies on modifying code the static_key_slow_{inc,dec}() functions
* must be considered absolute slow paths (machine wide synchronization etc.).
* OTOH, since the affected branches are unconditional their runtime overhead
* will be absolutely minimal, esp. in the default (off) case where the total
@ -26,12 +26,26 @@
*
* When the control is directly exposed to userspace it is prudent to delay the
* decrement to avoid high frequency code modifications which can (and do)
* cause significant performance degradation. Struct jump_label_key_deferred and
* jump_label_dec_deferred() provide for this.
* cause significant performance degradation. Struct static_key_deferred and
* static_key_slow_dec_deferred() provide for this.
*
* Lacking toolchain and or architecture support, it falls back to a simple
* conditional branch.
*/
*
* struct static_key my_key = STATIC_KEY_INIT_TRUE;
*
* if (static_key_true(&my_key)) {
* }
*
* will result in the true case being in-line and starts the key with a single
* reference. Mixing static_key_true() and static_key_false() on the same key is not
* allowed.
*
* Not initializing the key (static data is initialized to 0s anyway) is the
* same as using STATIC_KEY_INIT_FALSE and static_key_false() is
* equivalent with static_branch().
*
*/
#include <linux/types.h>
#include <linux/compiler.h>
@ -39,16 +53,17 @@
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
struct jump_label_key {
struct static_key {
atomic_t enabled;
/* Set lsb bit to 1 if branch is default true, 0 ot */
struct jump_entry *entries;
#ifdef CONFIG_MODULES
struct jump_label_mod *next;
struct static_key_mod *next;
#endif
};
struct jump_label_key_deferred {
struct jump_label_key key;
struct static_key_deferred {
struct static_key key;
unsigned long timeout;
struct delayed_work work;
};
@ -66,13 +81,34 @@ struct module;
#ifdef HAVE_JUMP_LABEL
#ifdef CONFIG_MODULES
#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL, NULL}
#else
#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL}
#endif
#define JUMP_LABEL_TRUE_BRANCH 1UL
static __always_inline bool static_branch(struct jump_label_key *key)
static
inline struct jump_entry *jump_label_get_entries(struct static_key *key)
{
return (struct jump_entry *)((unsigned long)key->entries
& ~JUMP_LABEL_TRUE_BRANCH);
}
static inline bool jump_label_get_branch_default(struct static_key *key)
{
if ((unsigned long)key->entries & JUMP_LABEL_TRUE_BRANCH)
return true;
return false;
}
static __always_inline bool static_key_false(struct static_key *key)
{
return arch_static_branch(key);
}
static __always_inline bool static_key_true(struct static_key *key)
{
return !static_key_false(key);
}
/* Deprecated. Please use 'static_key_false() instead. */
static __always_inline bool static_branch(struct static_key *key)
{
return arch_static_branch(key);
}
@ -88,21 +124,24 @@ extern void arch_jump_label_transform(struct jump_entry *entry,
extern void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type);
extern int jump_label_text_reserved(void *start, void *end);
extern void jump_label_inc(struct jump_label_key *key);
extern void jump_label_dec(struct jump_label_key *key);
extern void jump_label_dec_deferred(struct jump_label_key_deferred *key);
extern bool jump_label_enabled(struct jump_label_key *key);
extern void static_key_slow_inc(struct static_key *key);
extern void static_key_slow_dec(struct static_key *key);
extern void static_key_slow_dec_deferred(struct static_key_deferred *key);
extern bool static_key_enabled(struct static_key *key);
extern void jump_label_apply_nops(struct module *mod);
extern void jump_label_rate_limit(struct jump_label_key_deferred *key,
unsigned long rl);
extern void
jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl);
#define STATIC_KEY_INIT_TRUE ((struct static_key) \
{ .enabled = ATOMIC_INIT(1), .entries = (void *)1 })
#define STATIC_KEY_INIT_FALSE ((struct static_key) \
{ .enabled = ATOMIC_INIT(0), .entries = (void *)0 })
#else /* !HAVE_JUMP_LABEL */
#include <linux/atomic.h>
#define JUMP_LABEL_INIT {ATOMIC_INIT(0)}
struct jump_label_key {
struct static_key {
atomic_t enabled;
};
@ -110,30 +149,45 @@ static __always_inline void jump_label_init(void)
{
}
struct jump_label_key_deferred {
struct jump_label_key key;
struct static_key_deferred {
struct static_key key;
};
static __always_inline bool static_branch(struct jump_label_key *key)
static __always_inline bool static_key_false(struct static_key *key)
{
if (unlikely(atomic_read(&key->enabled)))
if (unlikely(atomic_read(&key->enabled)) > 0)
return true;
return false;
}
static inline void jump_label_inc(struct jump_label_key *key)
static __always_inline bool static_key_true(struct static_key *key)
{
if (likely(atomic_read(&key->enabled)) > 0)
return true;
return false;
}
/* Deprecated. Please use 'static_key_false() instead. */
static __always_inline bool static_branch(struct static_key *key)
{
if (unlikely(atomic_read(&key->enabled)) > 0)
return true;
return false;
}
static inline void static_key_slow_inc(struct static_key *key)
{
atomic_inc(&key->enabled);
}
static inline void jump_label_dec(struct jump_label_key *key)
static inline void static_key_slow_dec(struct static_key *key)
{
atomic_dec(&key->enabled);
}
static inline void jump_label_dec_deferred(struct jump_label_key_deferred *key)
static inline void static_key_slow_dec_deferred(struct static_key_deferred *key)
{
jump_label_dec(&key->key);
static_key_slow_dec(&key->key);
}
static inline int jump_label_text_reserved(void *start, void *end)
@ -144,9 +198,9 @@ static inline int jump_label_text_reserved(void *start, void *end)
static inline void jump_label_lock(void) {}
static inline void jump_label_unlock(void) {}
static inline bool jump_label_enabled(struct jump_label_key *key)
static inline bool static_key_enabled(struct static_key *key)
{
return !!atomic_read(&key->enabled);
return (atomic_read(&key->enabled) > 0);
}
static inline int jump_label_apply_nops(struct module *mod)
@ -154,13 +208,20 @@ static inline int jump_label_apply_nops(struct module *mod)
return 0;
}
static inline void jump_label_rate_limit(struct jump_label_key_deferred *key,
static inline void
jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)
{
}
#define STATIC_KEY_INIT_TRUE ((struct static_key) \
{ .enabled = ATOMIC_INIT(1) })
#define STATIC_KEY_INIT_FALSE ((struct static_key) \
{ .enabled = ATOMIC_INIT(0) })
#endif /* HAVE_JUMP_LABEL */
#define jump_label_key_enabled ((struct jump_label_key){ .enabled = ATOMIC_INIT(1), })
#define jump_label_key_disabled ((struct jump_label_key){ .enabled = ATOMIC_INIT(0), })
#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE
#define jump_label_enabled static_key_enabled
#endif /* _LINUX_JUMP_LABEL_H */

4
include/linux/netdevice.h
View file

@ -214,8 +214,8 @@ enum {
#include <linux/skbuff.h>
#ifdef CONFIG_RPS
#include <linux/jump_label.h>
extern struct jump_label_key rps_needed;
#include <linux/static_key.h>
extern struct static_key rps_needed;
#endif
struct neighbour;

6
include/linux/netfilter.h
View file

@ -163,13 +163,13 @@ extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
#if defined(CONFIG_JUMP_LABEL)
#include <linux/jump_label.h>
extern struct jump_label_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
#include <linux/static_key.h>
extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
{
if (__builtin_constant_p(pf) &&
__builtin_constant_p(hook))
return static_branch(&nf_hooks_needed[pf][hook]);
return static_key_false(&nf_hooks_needed[pf][hook]);
return !list_empty(&nf_hooks[pf][hook]);
}

12
include/linux/perf_event.h
View file

@ -514,7 +514,7 @@ struct perf_guest_info_callbacks {
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/irq_work.h>
#include <linux/jump_label.h>
#include <linux/static_key.h>
#include <linux/atomic.h>
#include <asm/local.h>
@ -1041,7 +1041,7 @@ static inline int is_software_event(struct perf_event *event)
return event->pmu->task_ctx_nr == perf_sw_context;
}
extern struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
extern struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
extern void __perf_sw_event(u32, u64, struct pt_regs *, u64);
@ -1069,7 +1069,7 @@ perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
struct pt_regs hot_regs;
if (static_branch(&perf_swevent_enabled[event_id])) {
if (static_key_false(&perf_swevent_enabled[event_id])) {
if (!regs) {
perf_fetch_caller_regs(&hot_regs);
regs = &hot_regs;
@ -1078,12 +1078,12 @@ perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
}
}
extern struct jump_label_key_deferred perf_sched_events;
extern struct static_key_deferred perf_sched_events;
static inline void perf_event_task_sched_in(struct task_struct *prev,
struct task_struct *task)
{
if (static_branch(&perf_sched_events.key))
if (static_key_false(&perf_sched_events.key))
__perf_event_task_sched_in(prev, task);
}
@ -1092,7 +1092,7 @@ static inline void perf_event_task_sched_out(struct task_struct *prev,
{
perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, NULL, 0);
if (static_branch(&perf_sched_events.key))
if (static_key_false(&perf_sched_events.key))
__perf_event_task_sched_out(prev, next);
}

1
include/linux/static_key.h Normal file
View file

@ -0,0 +1 @@
#include <linux/jump_label.h>

8
include/linux/tracepoint.h
View file

@ -17,7 +17,7 @@
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/jump_label.h>
#include <linux/static_key.h>
struct module;
struct tracepoint;
@ -29,7 +29,7 @@ struct tracepoint_func {
struct tracepoint {
const char *name; /* Tracepoint name */
struct jump_label_key key;
struct static_key key;
void (*regfunc)(void);
void (*unregfunc)(void);
struct tracepoint_func __rcu *funcs;
@ -145,7 +145,7 @@ static inline void tracepoint_synchronize_unregister(void)
extern struct tracepoint __tracepoint_##name; \
static inline void trace_##name(proto) \
{ \
if (static_branch(&__tracepoint_##name.key)) \
if (static_key_false(&__tracepoint_##name.key)) \
__DO_TRACE(&__tracepoint_##name, \
TP_PROTO(data_proto), \
TP_ARGS(data_args), \
@ -188,7 +188,7 @@ static inline void tracepoint_synchronize_unregister(void)
__attribute__((section("__tracepoints_strings"))) = #name; \
struct tracepoint __tracepoint_##name \
__attribute__((section("__tracepoints"))) = \
{ __tpstrtab_##name, JUMP_LABEL_INIT, reg, unreg, NULL };\
{ __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
static struct tracepoint * const __tracepoint_ptr_##name __used \
__attribute__((section("__tracepoints_ptrs"))) = \
&__tracepoint_##name;

6
include/net/sock.h
View file

@ -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,

16
kernel/events/core.c
View file

@ -128,7 +128,7 @@ enum event_type_t {
* perf_sched_events : >0 events exist
* perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
*/
struct jump_label_key_deferred perf_sched_events __read_mostly;
struct static_key_deferred perf_sched_events __read_mostly;
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
static atomic_t nr_mmap_events __read_mostly;
@ -2769,7 +2769,7 @@ static void free_event(struct perf_event *event)
if (!event->parent) {
if (event->attach_state & PERF_ATTACH_TASK)
jump_label_dec_deferred(&perf_sched_events);
static_key_slow_dec_deferred(&perf_sched_events);
if (event->attr.mmap || event->attr.mmap_data)
atomic_dec(&nr_mmap_events);
if (event->attr.comm)
@ -2780,7 +2780,7 @@ static void free_event(struct perf_event *event)
put_callchain_buffers();
if (is_cgroup_event(event)) {
atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
jump_label_dec_deferred(&perf_sched_events);
static_key_slow_dec_deferred(&perf_sched_events);
}
}
@ -4982,7 +4982,7 @@ static int swevent_hlist_get(struct perf_event *event)
return err;
}
struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
static void sw_perf_event_destroy(struct perf_event *event)
{
@ -4990,7 +4990,7 @@ static void sw_perf_event_destroy(struct perf_event *event)
WARN_ON(event->parent);
jump_label_dec(&perf_swevent_enabled[event_id]);
static_key_slow_dec(&perf_swevent_enabled[event_id]);
swevent_hlist_put(event);
}
@ -5020,7 +5020,7 @@ static int perf_swevent_init(struct perf_event *event)
if (err)
return err;
jump_label_inc(&perf_swevent_enabled[event_id]);
static_key_slow_inc(&perf_swevent_enabled[event_id]);
event->destroy = sw_perf_event_destroy;
}
@ -5843,7 +5843,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
if (!event->parent) {
if (event->attach_state & PERF_ATTACH_TASK)
jump_label_inc(&perf_sched_events.key);
static_key_slow_inc(&perf_sched_events.key);
if (event->attr.mmap || event->attr.mmap_data)
atomic_inc(&nr_mmap_events);
if (event->attr.comm)
@ -6081,7 +6081,7 @@ SYSCALL_DEFINE5(perf_event_open,
* - that may need work on context switch
*/
atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
jump_label_inc(&perf_sched_events.key);
static_key_slow_inc(&perf_sched_events.key);
}
/*

135
kernel/jump_label.c
View file

@ -12,7 +12,7 @@
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/err.h>
#include <linux/jump_label.h>
#include <linux/static_key.h>
#ifdef HAVE_JUMP_LABEL
@ -29,10 +29,11 @@ void jump_label_unlock(void)
mutex_unlock(&jump_label_mutex);
}
bool jump_label_enabled(struct jump_label_key *key)
bool static_key_enabled(struct static_key *key)
{
return !!atomic_read(&key->enabled);
return (atomic_read(&key->enabled) > 0);
}
EXPORT_SYMBOL_GPL(static_key_enabled);
static int jump_label_cmp(const void *a, const void *b)
{
@ -58,56 +59,66 @@ jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
}
static void jump_label_update(struct jump_label_key *key, int enable);
static void jump_label_update(struct static_key *key, int enable);
void jump_label_inc(struct jump_label_key *key)
void static_key_slow_inc(struct static_key *key)
{
if (atomic_inc_not_zero(&key->enabled))
return;
jump_label_lock();
if (atomic_read(&key->enabled) == 0)
jump_label_update(key, JUMP_LABEL_ENABLE);
if (atomic_read(&key->enabled) == 0) {
if (!jump_label_get_branch_default(key))
jump_label_update(key, JUMP_LABEL_ENABLE);
else
jump_label_update(key, JUMP_LABEL_DISABLE);
}
atomic_inc(&key->enabled);
jump_label_unlock();
}
EXPORT_SYMBOL_GPL(jump_label_inc);
EXPORT_SYMBOL_GPL(static_key_slow_inc);
static void __jump_label_dec(struct jump_label_key *key,
static void __static_key_slow_dec(struct static_key *key,
unsigned long rate_limit, struct delayed_work *work)
{
if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex))
if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
WARN(atomic_read(&key->enabled) < 0,
"jump label: negative count!\n");
return;
}
if (rate_limit) {
atomic_inc(&key->enabled);
schedule_delayed_work(work, rate_limit);
} else
jump_label_update(key, JUMP_LABEL_DISABLE);
} else {
if (!jump_label_get_branch_default(key))
jump_label_update(key, JUMP_LABEL_DISABLE);
else
jump_label_update(key, JUMP_LABEL_ENABLE);
}
jump_label_unlock();
}
EXPORT_SYMBOL_GPL(jump_label_dec);
static void jump_label_update_timeout(struct work_struct *work)
{
struct jump_label_key_deferred *key =
container_of(work, struct jump_label_key_deferred, work.work);
__jump_label_dec(&key->key, 0, NULL);
struct static_key_deferred *key =
container_of(work, struct static_key_deferred, work.work);
__static_key_slow_dec(&key->key, 0, NULL);
}
void jump_label_dec(struct jump_label_key *key)
void static_key_slow_dec(struct static_key *key)
{
__jump_label_dec(key, 0, NULL);
__static_key_slow_dec(key, 0, NULL);
}
EXPORT_SYMBOL_GPL(static_key_slow_dec);
void jump_label_dec_deferred(struct jump_label_key_deferred *key)
void static_key_slow_dec_deferred(struct static_key_deferred *key)
{
__jump_label_dec(&key->key, key->timeout, &key->work);
__static_key_slow_dec(&key->key, key->timeout, &key->work);
}
EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
void jump_label_rate_limit(struct jump_label_key_deferred *key,
void jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)
{
key->timeout = rl;
@ -150,7 +161,7 @@ void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry
arch_jump_label_transform(entry, type);
}
static void __jump_label_update(struct jump_label_key *key,
static void __jump_label_update(struct static_key *key,
struct jump_entry *entry,
struct jump_entry *stop, int enable)
{
@ -167,27 +178,40 @@ static void __jump_label_update(struct jump_label_key *key,
}
}
static enum jump_label_type jump_label_type(struct static_key *key)
{
bool true_branch = jump_label_get_branch_default(key);
bool state = static_key_enabled(key);
if ((!true_branch && state) || (true_branch && !state))
return JUMP_LABEL_ENABLE;
return JUMP_LABEL_DISABLE;
}
void __init jump_label_init(void)
{
struct jump_entry *iter_start = __start___jump_table;
struct jump_entry *iter_stop = __stop___jump_table;
struct jump_label_key *key = NULL;
struct static_key *key = NULL;
struct jump_entry *iter;
jump_label_lock();
jump_label_sort_entries(iter_start, iter_stop);
for (iter = iter_start; iter < iter_stop; iter++) {
struct jump_label_key *iterk;
struct static_key *iterk;
iterk = (struct jump_label_key *)(unsigned long)iter->key;
arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ?
JUMP_LABEL_ENABLE : JUMP_LABEL_DISABLE);
iterk = (struct static_key *)(unsigned long)iter->key;
arch_jump_label_transform_static(iter, jump_label_type(iterk));
if (iterk == key)
continue;
key = iterk;
key->entries = iter;
/*
* Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
*/
*((unsigned long *)&key->entries) += (unsigned long)iter;
#ifdef CONFIG_MODULES
key->next = NULL;
#endif
@ -197,8 +221,8 @@ void __init jump_label_init(void)
#ifdef CONFIG_MODULES
struct jump_label_mod {
struct jump_label_mod *next;
struct static_key_mod {
struct static_key_mod *next;
struct jump_entry *entries;
struct module *mod;
};
@ -218,9 +242,9 @@ static int __jump_label_mod_text_reserved(void *start, void *end)
start, end);
}
static void __jump_label_mod_update(struct jump_label_key *key, int enable)
static void __jump_label_mod_update(struct static_key *key, int enable)
{
struct jump_label_mod *mod = key->next;
struct static_key_mod *mod = key->next;
while (mod) {
struct module *m = mod->mod;
@ -251,11 +275,7 @@ void jump_label_apply_nops(struct module *mod)
return;
for (iter = iter_start; iter < iter_stop; iter++) {
struct jump_label_key *iterk;
iterk = (struct jump_label_key *)(unsigned long)iter->key;
arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ?
JUMP_LABEL_ENABLE : JUMP_LABEL_DISABLE);
arch_jump_label_transform_static(iter, JUMP_LABEL_DISABLE);
}
}
@ -264,8 +284,8 @@ static int jump_label_add_module(struct module *mod)
struct jump_entry *iter_start = mod->jump_entries;
struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
struct jump_entry *iter;
struct jump_label_key *key = NULL;
struct jump_label_mod *jlm;
struct static_key *key = NULL;
struct static_key_mod *jlm;
/* if the module doesn't have jump label entries, just return */
if (iter_start == iter_stop)
@ -274,28 +294,30 @@ static int jump_label_add_module(struct module *mod)
jump_label_sort_entries(iter_start, iter_stop);
for (iter = iter_start; iter < iter_stop; iter++) {
if (iter->key == (jump_label_t)(unsigned long)key)
struct static_key *iterk;
iterk = (struct static_key *)(unsigned long)iter->key;
if (iterk == key)
continue;
key = (struct jump_label_key *)(unsigned long)iter->key;
key = iterk;
if (__module_address(iter->key) == mod) {
atomic_set(&key->enabled, 0);
key->entries = iter;
/*
* Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
*/
*((unsigned long *)&key->entries) += (unsigned long)iter;
key->next = NULL;
continue;
}
jlm = kzalloc(sizeof(struct jump_label_mod), GFP_KERNEL);
jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
if (!jlm)
return -ENOMEM;
jlm->mod = mod;
jlm->entries = iter;
jlm->next = key->next;
key->next = jlm;
if (jump_label_enabled(key))
if (jump_label_type(key) == JUMP_LABEL_ENABLE)
__jump_label_update(key, iter, iter_stop, JUMP_LABEL_ENABLE);
}
@ -307,14 +329,14 @@ static void jump_label_del_module(struct module *mod)
struct jump_entry *iter_start = mod->jump_entries;
struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
struct jump_entry *iter;
struct jump_label_key *key = NULL;
struct jump_label_mod *jlm, **prev;
struct static_key *key = NULL;
struct static_key_mod *jlm, **prev;
for (iter = iter_start; iter < iter_stop; iter++) {
if (iter->key == (jump_label_t)(unsigned long)key)
continue;
key = (struct jump_label_key *)(unsigned long)iter->key;
key = (struct static_key *)(unsigned long)iter->key;
if (__module_address(iter->key) == mod)
continue;
@ -416,12 +438,13 @@ int jump_label_text_reserved(void *start, void *end)
return ret;
}
static void jump_label_update(struct jump_label_key *key, int enable)
static void jump_label_update(struct static_key *key, int enable)
{
struct jump_entry *entry = key->entries, *stop = __stop___jump_table;
struct jump_entry *stop = __stop___jump_table;
struct jump_entry *entry = jump_label_get_entries(key);
#ifdef CONFIG_MODULES
struct module *mod = __module_address((jump_label_t)key);
struct module *mod = __module_address((unsigned long)key);
__jump_label_mod_update(key, enable);

18
kernel/sched/core.c
View file

@ -162,13 +162,13 @@ static int sched_feat_show(struct seq_file *m, void *v)
#ifdef HAVE_JUMP_LABEL
#define jump_label_key__true jump_label_key_enabled
#define jump_label_key__false jump_label_key_disabled
#define jump_label_key__true STATIC_KEY_INIT_TRUE
#define jump_label_key__false STATIC_KEY_INIT_FALSE
#define SCHED_FEAT(name, enabled) \
jump_label_key__##enabled ,
struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR] = {
struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
#include "features.h"
};
@ -176,14 +176,14 @@ struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR] = {
static void sched_feat_disable(int i)
{
if (jump_label_enabled(&sched_feat_keys[i]))
jump_label_dec(&sched_feat_keys[i]);
if (static_key_enabled(&sched_feat_keys[i]))
static_key_slow_dec(&sched_feat_keys[i]);
}
static void sched_feat_enable(int i)
{
if (!jump_label_enabled(&sched_feat_keys[i]))
jump_label_inc(&sched_feat_keys[i]);
if (!static_key_enabled(&sched_feat_keys[i]))
static_key_slow_inc(&sched_feat_keys[i]);
}
#else
static void sched_feat_disable(int i) { };
@ -894,7 +894,7 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
delta -= irq_delta;
#endif
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
if (static_branch((&paravirt_steal_rq_enabled))) {
if (static_key_false((&paravirt_steal_rq_enabled))) {
u64 st;
steal = paravirt_steal_clock(cpu_of(rq));
@ -2756,7 +2756,7 @@ void account_idle_time(cputime_t cputime)
static __always_inline bool steal_account_process_tick(void)
{
#ifdef CONFIG_PARAVIRT
if (static_branch(&paravirt_steal_enabled)) {
if (static_key_false(&paravirt_steal_enabled)) {
u64 steal, st = 0;
steal = paravirt_steal_clock(smp_processor_id());

8
kernel/sched/fair.c
View file

@ -1399,20 +1399,20 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
#ifdef CONFIG_CFS_BANDWIDTH
#ifdef HAVE_JUMP_LABEL
static struct jump_label_key __cfs_bandwidth_used;
static struct static_key __cfs_bandwidth_used;
static inline bool cfs_bandwidth_used(void)
{
return static_branch(&__cfs_bandwidth_used);
return static_key_false(&__cfs_bandwidth_used);
}
void account_cfs_bandwidth_used(int enabled, int was_enabled)
{
/* only need to count groups transitioning between enabled/!enabled */
if (enabled && !was_enabled)
jump_label_inc(&__cfs_bandwidth_used);
static_key_slow_inc(&__cfs_bandwidth_used);
else if (!enabled && was_enabled)
jump_label_dec(&__cfs_bandwidth_used);
static_key_slow_dec(&__cfs_bandwidth_used);
}
#else /* HAVE_JUMP_LABEL */
static bool cfs_bandwidth_used(void)

14
kernel/sched/sched.h
View file

@ -611,7 +611,7 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
* Tunables that become constants when CONFIG_SCHED_DEBUG is off:
*/
#ifdef CONFIG_SCHED_DEBUG
# include <linux/jump_label.h>
# include <linux/static_key.h>
# define const_debug __read_mostly
#else
# define const_debug const
@ -630,18 +630,18 @@ enum {
#undef SCHED_FEAT
#if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
static __always_inline bool static_branch__true(struct jump_label_key *key)
static __always_inline bool static_branch__true(struct static_key *key)
{
return likely(static_branch(key)); /* Not out of line branch. */
return static_key_true(key); /* Not out of line branch. */
}
static __always_inline bool static_branch__false(struct jump_label_key *key)
static __always_inline bool static_branch__false(struct static_key *key)
{
return unlikely(static_branch(key)); /* Out of line branch. */
return static_key_false(key); /* Out of line branch. */
}
#define SCHED_FEAT(name, enabled) \
static __always_inline bool static_branch_##name(struct jump_label_key *key) \
static __always_inline bool static_branch_##name(struct static_key *key) \
{ \
return static_branch__##enabled(key); \
}
@ -650,7 +650,7 @@ static __always_inline bool static_branch_##name(struct jump_label_key *key) \
#undef SCHED_FEAT
extern struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR];
extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
#else /* !(SCHED_DEBUG && HAVE_JUMP_LABEL) */
#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))

20
kernel/tracepoint.c
View file

@ -25,7 +25,7 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/jump_label.h>
#include <linux/static_key.h>
extern struct tracepoint * const __start___tracepoints_ptrs[];
extern struct tracepoint * const __stop___tracepoints_ptrs[];
@ -256,9 +256,9 @@ static void set_tracepoint(struct tracepoint_entry **entry,
{
WARN_ON(strcmp((*entry)->name, elem->name) != 0);
if (elem->regfunc && !jump_label_enabled(&elem->key) && active)
if (elem->regfunc && !static_key_enabled(&elem->key) && active)
elem->regfunc();
else if (elem->unregfunc && jump_label_enabled(&elem->key) && !active)
else if (elem->unregfunc && static_key_enabled(&elem->key) && !active)
elem->unregfunc();
/*
@ -269,10 +269,10 @@ static void set_tracepoint(struct tracepoint_entry **entry,
* is used.
*/
rcu_assign_pointer(elem->funcs, (*entry)->funcs);
if (active && !jump_label_enabled(&elem->key))
jump_label_inc(&elem->key);
else if (!active && jump_label_enabled(&elem->key))
jump_label_dec(&elem->key);
if (active && !static_key_enabled(&elem->key))
static_key_slow_inc(&elem->key);
else if (!active && static_key_enabled(&elem->key))
static_key_slow_dec(&elem->key);
}
/*
@ -283,11 +283,11 @@ static void set_tracepoint(struct tracepoint_entry **entry,
*/
static void disable_tracepoint(struct tracepoint *elem)
{
if (elem->unregfunc && jump_label_enabled(&elem->key))
if (elem->unregfunc && static_key_enabled(&elem->key))
elem->unregfunc();
if (jump_label_enabled(&elem->key))
jump_label_dec(&elem->key);
if (static_key_enabled(&elem->key))
static_key_slow_dec(&elem->key);
rcu_assign_pointer(elem->funcs, NULL);
}

24
net/core/dev.c
View file

@ -134,7 +134,7 @@
#include <linux/inetdevice.h>
#include <linux/cpu_rmap.h>
#include <linux/net_tstamp.h>
#include <linux/jump_label.h>
#include <linux/static_key.h>
#include <net/flow_keys.h>
#include "net-sysfs.h"
@ -1441,11 +1441,11 @@ int call_netdevice_notifiers(unsigned long val, struct net_device *dev)
}
EXPORT_SYMBOL(call_netdevice_notifiers);
static struct jump_label_key netstamp_needed __read_mostly;
static struct static_key netstamp_needed __read_mostly;
#ifdef HAVE_JUMP_LABEL
/* We are not allowed to call jump_label_dec() from irq context
/* We are not allowed to call static_key_slow_dec() from irq context
* If net_disable_timestamp() is called from irq context, defer the
* jump_label_dec() calls.
* static_key_slow_dec() calls.
*/
static atomic_t netstamp_needed_deferred;
#endif
@ -1457,12 +1457,12 @@ void net_enable_timestamp(void)
if (deferred) {
while (--deferred)
jump_label_dec(&netstamp_needed);
static_key_slow_dec(&netstamp_needed);
return;
}
#endif
WARN_ON(in_interrupt());
jump_label_inc(&netstamp_needed);
static_key_slow_inc(&netstamp_needed);
}
EXPORT_SYMBOL(net_enable_timestamp);
@ -1474,19 +1474,19 @@ void net_disable_timestamp(void)
return;
}
#endif
jump_label_dec(&netstamp_needed);
static_key_slow_dec(&netstamp_needed);
}
EXPORT_SYMBOL(net_disable_timestamp);
static inline void net_timestamp_set(struct sk_buff *skb)
{
skb->tstamp.tv64 = 0;
if (static_branch(&netstamp_needed))
if (static_key_false(&netstamp_needed))
__net_timestamp(skb);
}
#define net_timestamp_check(COND, SKB) \
if (static_branch(&netstamp_needed)) { \
if (static_key_false(&netstamp_needed)) { \
if ((COND) && !(SKB)->tstamp.tv64) \
__net_timestamp(SKB); \
} \
@ -2660,7 +2660,7 @@ EXPORT_SYMBOL(__skb_get_rxhash);
struct rps_sock_flow_table __rcu *rps_sock_flow_table __read_mostly;
EXPORT_SYMBOL(rps_sock_flow_table);
struct jump_label_key rps_needed __read_mostly;
struct static_key rps_needed __read_mostly;
static struct rps_dev_flow *
set_rps_cpu(struct net_device *dev, struct sk_buff *skb,
@ -2945,7 +2945,7 @@ int netif_rx(struct sk_buff *skb)
trace_netif_rx(skb);
#ifdef CONFIG_RPS
if (static_branch(&rps_needed)) {
if (static_key_false(&rps_needed)) {
struct rps_dev_flow voidflow, *rflow = &voidflow;
int cpu;
@ -3309,7 +3309,7 @@ int netif_receive_skb(struct sk_buff *skb)
return NET_RX_SUCCESS;
#ifdef CONFIG_RPS
if (static_branch(&rps_needed)) {
if (static_key_false(&rps_needed)) {
struct rps_dev_flow voidflow, *rflow = &voidflow;
int cpu, ret;

4
net/core/net-sysfs.c
View file

@ -608,10 +608,10 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue,
spin_unlock(&rps_map_lock);
if (map)
jump_label_inc(&rps_needed);
static_key_slow_inc(&rps_needed);
if (old_map) {
kfree_rcu(old_map, rcu);
jump_label_dec(&rps_needed);
static_key_slow_dec(&rps_needed);
}
free_cpumask_var(mask);
return len;

4
net/core/sock.c
View file

@ -111,7 +111,7 @@
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/user_namespace.h>
#include <linux/jump_label.h>
#include <linux/static_key.h>
#include <linux/memcontrol.h>
#include <asm/uaccess.h>
@ -184,7 +184,7 @@ void mem_cgroup_sockets_destroy(struct cgroup *cgrp, struct cgroup_subsys *ss)
static struct lock_class_key af_family_keys[AF_MAX];
static struct lock_class_key af_family_slock_keys[AF_MAX];
struct jump_label_key memcg_socket_limit_enabled;
struct static_key memcg_socket_limit_enabled;
EXPORT_SYMBOL(memcg_socket_limit_enabled);
/*

4
net/core/sysctl_net_core.c
View file

@ -69,9 +69,9 @@ static int rps_sock_flow_sysctl(ctl_table *table, int write,
if (sock_table != orig_sock_table) {
rcu_assign_pointer(rps_sock_flow_table, sock_table);
if (sock_table)
jump_label_inc(&rps_needed);
static_key_slow_inc(&rps_needed);
if (orig_sock_table) {
jump_label_dec(&rps_needed);
static_key_slow_dec(&rps_needed);
synchronize_rcu();
vfree(orig_sock_table);
}

6
net/ipv4/tcp_memcontrol.c
View file

@ -111,7 +111,7 @@ void tcp_destroy_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
val = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
if (val != RESOURCE_MAX)
jump_label_dec(&memcg_socket_limit_enabled);
static_key_slow_dec(&memcg_socket_limit_enabled);
}
EXPORT_SYMBOL(tcp_destroy_cgroup);
@ -143,9 +143,9 @@ static int tcp_update_limit(struct mem_cgroup *memcg, u64 val)
net->ipv4.sysctl_tcp_mem[i]);
if (val == RESOURCE_MAX && old_lim != RESOURCE_MAX)
jump_label_dec(&memcg_socket_limit_enabled);
static_key_slow_dec(&memcg_socket_limit_enabled);
else if (old_lim == RESOURCE_MAX && val != RESOURCE_MAX)
jump_label_inc(&memcg_socket_limit_enabled);
static_key_slow_inc(&memcg_socket_limit_enabled);
return 0;
}

6
net/netfilter/core.c
View file

@ -56,7 +56,7 @@ struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS] __read_mostly;
EXPORT_SYMBOL(nf_hooks);
#if defined(CONFIG_JUMP_LABEL)
struct jump_label_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
EXPORT_SYMBOL(nf_hooks_needed);
#endif
@ -77,7 +77,7 @@ int nf_register_hook(struct nf_hook_ops *reg)
list_add_rcu(&reg->list, elem->list.prev);
mutex_unlock(&nf_hook_mutex);
#if defined(CONFIG_JUMP_LABEL)
jump_label_inc(&nf_hooks_needed[reg->pf][reg->hooknum]);
static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]);
#endif
return 0;
}
@ -89,7 +89,7 @@ void nf_unregister_hook(struct nf_hook_ops *reg)
list_del_rcu(&reg->list);
mutex_unlock(&nf_hook_mutex);
#if defined(CONFIG_JUMP_LABEL)
jump_label_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
#endif
synchronize_net();
}