From 607abbfb4d7b1052e7d35fb9aa7fd24ab79182ec Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 1 Nov 2012 11:03:47 +0100 Subject: x86-preempt-lazy.patch Signed-off-by: Thomas Gleixner diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 083ee96..edbb857 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -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 HAVE_AOUT if X86_32 select HAVE_UNSTABLE_SCHED_CLOCK diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 2781119..f08e527 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -30,6 +30,8 @@ struct thread_info { __u32 cpu; /* current CPU */ int preempt_count; /* 0 => preemptable, <0 => BUG */ + int preempt_lazy_count; /* 0 => lazy preemptable, + <0 => BUG */ mm_segment_t addr_limit; struct restart_block restart_block; void __user *sysenter_return; @@ -81,6 +83,7 @@ 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 */ @@ -105,6 +108,7 @@ 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) @@ -154,6 +158,8 @@ 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) + #define PREEMPT_ACTIVE 0x10000000 #ifdef CONFIG_X86_32 diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 2861082..a36d9cf 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -33,6 +33,7 @@ void common(void) { OFFSET(TI_status, thread_info, status); OFFSET(TI_addr_limit, thread_info, addr_limit); OFFSET(TI_preempt_count, thread_info, preempt_count); + OFFSET(TI_preempt_lazy_count, thread_info, preempt_lazy_count); BLANK(); OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx); diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 15a569a..e491bfd 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -364,14 +364,22 @@ ENTRY(resume_kernel) DISABLE_INTERRUPTS(CLBR_ANY) cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ? jnz restore_all -need_resched: movl TI_flags(%ebp), %ecx # need_resched set ? testb $_TIF_NEED_RESCHED, %cl + jnz 1f + + cmpl $0,TI_preempt_lazy_count(%ebp) # non-zero preempt_lazy_count ? + jnz restore_all + testl $_TIF_NEED_RESCHED_LAZY, %ecx jz restore_all - testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ? + +1: testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ? jz restore_all call preempt_schedule_irq - jmp need_resched + movl TI_flags(%ebp), %ecx # need_resched set ? + testl $_TIF_NEED_RESCHED_MASK, %ecx + jnz 1b + jmp restore_all END(resume_kernel) #endif CFI_ENDPROC @@ -607,7 +615,7 @@ 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 @@ -620,7 +628,7 @@ 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 diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 0db3eeb..abca4f4 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -658,8 +658,8 @@ 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 @@ -771,8 +771,8 @@ 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 @@ -1071,8 +1071,8 @@ bad_iret: /* 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 @@ -1105,9 +1105,15 @@ retint_signal: ENTRY(retint_kernel) cmpl $0,TI_preempt_count(%rcx) jnz retint_restore_args - bt $TIF_NEED_RESCHED,TI_flags(%rcx) + bt $TIF_NEED_RESCHED,TI_flags(%rcx) + jc 1f + + cmpl $0,TI_preempt_lazy_count(%rcx) + jnz retint_restore_args + bt $TIF_NEED_RESCHED_LAZY,TI_flags(%rcx) jnc retint_restore_args - bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */ + +1: bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */ jnc retint_restore_args call preempt_schedule_irq jmp exit_intr @@ -1531,7 +1537,7 @@ 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 -- cgit v0.10.2