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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-01 10:16:42 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-01 10:16:42 -0700 |
commit | 620e77533f29796df7aff861e79bd72e08554ebb (patch) | |
tree | 844afce2333549bc5b8d7dc87a4875b9216a0023 /arch/x86/include | |
parent | 6977b4c7736e8809b7959c66875a16c0bbcf2152 (diff) | |
parent | fa34da708cbe1e2d9a2ee7fc68ea8fccbf095d12 (diff) | |
download | linux-620e77533f29796df7aff861e79bd72e08554ebb.tar.bz2 |
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU changes from Ingo Molnar:
0. 'idle RCU':
Adds RCU APIs that allow non-idle tasks to enter RCU idle mode and
provides x86 code to make use of them, allowing RCU to treat
user-mode execution as an extended quiescent state when the new
RCU_USER_QS kernel configuration parameter is specified. (Work is
in progress to port this to a few other architectures, but is not
part of this series.)
1. A fix for a latent bug that has been in RCU ever since the addition
of CPU stall warnings. This bug results in false-positive stall
warnings, but thus far only on embedded systems with severely
cut-down userspace configurations.
2. Further reductions in latency spikes for huge systems, along with
additional boot-time adaptation to the actual hardware.
This is a large change, as it moves RCU grace-period initialization
and cleanup, along with quiescent-state forcing, from softirq to a
kthread. However, it appears to be in quite good shape (famous
last words).
3. Updates to documentation and rcutorture, the latter category
including keeping statistics on CPU-hotplug latencies and fixing
some initialization-time races.
4. CPU-hotplug fixes and improvements.
5. Idle-loop fixes that were omitted on an earlier submission.
6. Miscellaneous fixes and improvements
In certain RCU configurations new kernel threads will show up (rcu_bh,
rcu_sched), showing RCU processing overhead.
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
rcu: Apply micro-optimization and int/bool fixes to RCU's idle handling
rcu: Userspace RCU extended QS selftest
x86: Exit RCU extended QS on notify resume
x86: Use the new schedule_user API on userspace preemption
rcu: Exit RCU extended QS on user preemption
rcu: Exit RCU extended QS on kernel preemption after irq/exception
x86: Exception hooks for userspace RCU extended QS
x86: Unspaghettize do_general_protection()
x86: Syscall hooks for userspace RCU extended QS
rcu: Switch task's syscall hooks on context switch
rcu: Ignore userspace extended quiescent state by default
rcu: Allow rcu_user_enter()/exit() to nest
rcu: Settle config for userspace extended quiescent state
rcu: Make RCU_FAST_NO_HZ handle adaptive ticks
rcu: New rcu_user_enter_after_irq() and rcu_user_exit_after_irq() APIs
rcu: New rcu_user_enter() and rcu_user_exit() APIs
ia64: Add missing RCU idle APIs on idle loop
xtensa: Add missing RCU idle APIs on idle loop
score: Add missing RCU idle APIs on idle loop
parisc: Add missing RCU idle APIs on idle loop
...
Diffstat (limited to 'arch/x86/include')
-rw-r--r-- | arch/x86/include/asm/rcu.h | 32 | ||||
-rw-r--r-- | arch/x86/include/asm/thread_info.h | 10 |
2 files changed, 39 insertions, 3 deletions
diff --git a/arch/x86/include/asm/rcu.h b/arch/x86/include/asm/rcu.h new file mode 100644 index 000000000000..d1ac07a23979 --- /dev/null +++ b/arch/x86/include/asm/rcu.h @@ -0,0 +1,32 @@ +#ifndef _ASM_X86_RCU_H +#define _ASM_X86_RCU_H + +#ifndef __ASSEMBLY__ + +#include <linux/rcupdate.h> +#include <asm/ptrace.h> + +static inline void exception_enter(struct pt_regs *regs) +{ + rcu_user_exit(); +} + +static inline void exception_exit(struct pt_regs *regs) +{ +#ifdef CONFIG_RCU_USER_QS + if (user_mode(regs)) + rcu_user_enter(); +#endif +} + +#else /* __ASSEMBLY__ */ + +#ifdef CONFIG_RCU_USER_QS +# define SCHEDULE_USER call schedule_user +#else +# define SCHEDULE_USER call schedule +#endif + +#endif /* !__ASSEMBLY__ */ + +#endif diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 89f794f007ec..c535d847e3b5 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -89,6 +89,7 @@ struct thread_info { #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_IA32 17 /* IA32 compatibility process */ #define TIF_FORK 18 /* ret_from_fork */ +#define TIF_NOHZ 19 /* in adaptive nohz mode */ #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ #define TIF_DEBUG 21 /* uses debug registers */ #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ @@ -114,6 +115,7 @@ struct thread_info { #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_IA32 (1 << TIF_IA32) #define _TIF_FORK (1 << TIF_FORK) +#define _TIF_NOHZ (1 << TIF_NOHZ) #define _TIF_DEBUG (1 << TIF_DEBUG) #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) @@ -126,12 +128,13 @@ struct thread_info { /* work to do in syscall_trace_enter() */ #define _TIF_WORK_SYSCALL_ENTRY \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \ - _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT) + _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT | \ + _TIF_NOHZ) /* work to do in syscall_trace_leave() */ #define _TIF_WORK_SYSCALL_EXIT \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP | \ - _TIF_SYSCALL_TRACEPOINT) + _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ) /* work to do on interrupt/exception return */ #define _TIF_WORK_MASK \ @@ -141,7 +144,8 @@ struct thread_info { /* work to do on any return to user space */ #define _TIF_ALLWORK_MASK \ - ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT) + ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \ + _TIF_NOHZ) /* Only used for 64 bit */ #define _TIF_DO_NOTIFY_MASK \ |