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x86-preempt-lazy.patch 

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2012-11-01 11:03:47 +01:00 committed by Alibek Omarov
parent b33545443e
commit 5ccf423693
5 changed files with 49 additions and 9 deletions
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1
arch/x86/Kconfig
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@ -21,6 +21,7 @@ config X86_64
### Arch settings
config X86
def_bool y
select HAVE_PREEMPT_LAZY
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO

6
arch/x86/include/asm/thread_info.h
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@ -29,6 +29,8 @@ struct thread_info {
__u32 status; /* thread synchronous flags */
__u32 cpu; /* current CPU */
int saved_preempt_count;
int preempt_lazy_count; /* 0 => lazy preemptable
<0 => BUG */
mm_segment_t addr_limit;
struct restart_block restart_block;
void __user *sysenter_return;
@ -80,6 +82,7 @@ struct thread_info {
#define TIF_SYSCALL_EMU 6 /* syscall emulation active */
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_NEED_RESCHED_LAZY 9 /* lazy rescheduling necessary */
#define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */
#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
#define TIF_UPROBE 12 /* breakpointed or singlestepping */
@ -104,6 +107,7 @@ struct thread_info {
#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY)
#define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY)
#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
#define _TIF_UPROBE (1 << TIF_UPROBE)
@ -153,6 +157,8 @@ struct thread_info {
#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
#define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
#ifdef CONFIG_X86_32
#define STACK_WARN (THREAD_SIZE/8)

2
arch/x86/kernel/asm-offsets.c
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@ -32,6 +32,7 @@ void common(void) {
OFFSET(TI_flags, thread_info, flags);
OFFSET(TI_status, thread_info, status);
OFFSET(TI_addr_limit, thread_info, addr_limit);
OFFSET(TI_preempt_lazy_count, thread_info, preempt_lazy_count);
BLANK();
OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx);
@ -71,4 +72,5 @@ void common(void) {
BLANK();
DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
DEFINE(_PREEMPT_ENABLED, PREEMPT_ENABLED);
}

20
arch/x86/kernel/entry_32.S
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@ -363,8 +363,24 @@ END(ret_from_exception)
ENTRY(resume_kernel)
DISABLE_INTERRUPTS(CLBR_ANY)
need_resched:
# preempt count == 0 + NEED_RS set?
cmpl $0,PER_CPU_VAR(__preempt_count)
#ifndef CONFIG_PREEMPT_LAZY
jnz restore_all
#else
jz test_int_off
# atleast preempt count == 0 ?
cmpl $_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count)
jne restore_all
cmpl $0,TI_preempt_lazy_count(%ebp) # non-zero preempt_lazy_count ?
jnz restore_all
testl $_TIF_NEED_RESCHED_LAZY, TI_flags(%ebp)
jz restore_all
test_int_off:
#endif
testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
jz restore_all
call preempt_schedule_irq
@ -605,7 +621,7 @@ ENDPROC(system_call)
ALIGN
RING0_PTREGS_FRAME # can't unwind into user space anyway
work_pending:
testb $_TIF_NEED_RESCHED, %cl
testl $_TIF_NEED_RESCHED_MASK, %ecx
jz work_notifysig
work_resched:
call schedule
@ -618,7 +634,7 @@ work_resched:
andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
# than syscall tracing?
jz restore_all
testb $_TIF_NEED_RESCHED, %cl
testl $_TIF_NEED_RESCHED_MASK, %ecx
jnz work_resched
work_notifysig: # deal with pending signals and

29
arch/x86/kernel/entry_64.S
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@ -662,8 +662,8 @@ sysret_check:
/* Handle reschedules */
/* edx: work, edi: workmask */
sysret_careful:
bt $TIF_NEED_RESCHED,%edx
jnc sysret_signal
testl $_TIF_NEED_RESCHED_MASK,%edx
jz sysret_signal
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
pushq_cfi %rdi
@ -775,8 +775,8 @@ GLOBAL(int_with_check)
/* First do a reschedule test. */
/* edx: work, edi: workmask */
int_careful:
bt $TIF_NEED_RESCHED,%edx
jnc int_very_careful
testl $_TIF_NEED_RESCHED_MASK,%edx
jz int_very_careful
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
pushq_cfi %rdi
@ -1095,8 +1095,8 @@ native_irq_return_ldt:
/* edi: workmask, edx: work */
retint_careful:
CFI_RESTORE_STATE
bt $TIF_NEED_RESCHED,%edx
jnc retint_signal
testl $_TIF_NEED_RESCHED_MASK,%edx
jz retint_signal
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
pushq_cfi %rdi
@ -1128,7 +1128,22 @@ retint_signal:
/* rcx: threadinfo. interrupts off. */
ENTRY(retint_kernel)
cmpl $0,PER_CPU_VAR(__preempt_count)
#ifndef CONFIG_PREEMPT_LAZY
jnz retint_restore_args
#else
jz check_int_off
# atleast preempt count == 0 ?
cmpl $_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count)
jnz retint_restore_args
cmpl $0, TI_preempt_lazy_count(%rcx)
jnz retint_restore_args
bt $TIF_NEED_RESCHED_LAZY,TI_flags(%rcx)
jnc retint_restore_args
check_int_off:
#endif
bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
jnc retint_restore_args
call preempt_schedule_irq
@ -1564,7 +1579,7 @@ paranoid_userspace:
movq %rsp,%rdi /* &pt_regs */
call sync_regs
movq %rax,%rsp /* switch stack for scheduling */
testl $_TIF_NEED_RESCHED,%ebx
testl $_TIF_NEED_RESCHED_MASK,%ebx
jnz paranoid_schedule
movl %ebx,%edx /* arg3: thread flags */
TRACE_IRQS_ON