From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: RT <linux-rt-users@vger.kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [patch 2/6] x86/preempt-lazy adapt implementation to percpu __preempt_count
Date: Fri, 02 May 2014 13:12:56 +0200 [thread overview]
Message-ID: <1399029176.5233.126.camel@marge.simpson.net> (raw)
In-Reply-To: <1399020080.5233.96.camel@marge.simpson.net>
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
---
arch/x86/include/asm/preempt.h | 8 ++++++++
arch/x86/kernel/asm-offsets.c | 1 +
arch/x86/kernel/entry_32.S | 9 ++++++---
arch/x86/kernel/entry_64.S | 7 +++++--
4 files changed, 20 insertions(+), 5 deletions(-)
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -94,7 +94,11 @@ static __always_inline bool __preempt_co
{
if (____preempt_count_dec_and_test())
return true;
+#ifdef CONFIG_PREEMPT_LAZY
return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
+ return false;
+#endif
}
/*
@@ -102,8 +106,12 @@ static __always_inline bool __preempt_co
*/
static __always_inline bool should_resched(void)
{
+#ifdef CONFIG_PREEMPT_LAZY
return unlikely(!__this_cpu_read_4(__preempt_count) || \
test_thread_flag(TIF_NEED_RESCHED_LAZY));
+#else
+ return unlikely(!__this_cpu_read_4(__preempt_count));
+#endif
}
#ifdef CONFIG_PREEMPT
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -72,4 +72,5 @@ void common(void) {
BLANK();
DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
+ DEFINE(_PREEMPT_ENABLED, PREEMPT_ENABLED);
}
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -365,19 +365,22 @@ ENTRY(resume_kernel)
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 $_TIF_NEED_RESCHED,PER_CPU_VAR(__preempt_count)
+ 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, %ecx
+ 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
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1104,10 +1104,13 @@ ENTRY(native_iret)
/* 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 $_TIF_NEED_RESCHED,PER_CPU_VAR(__preempt_count)
+ cmpl $_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count)
jnz retint_restore_args
cmpl $0, TI_preempt_lazy_count(%rcx)
@@ -1115,8 +1118,8 @@ ENTRY(retint_kernel)
bt $TIF_NEED_RESCHED_LAZY,TI_flags(%rcx)
jnc retint_restore_args
next prev parent reply other threads:[~2014-05-02 11:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1399020080.5233.96.camel@marge.simpson.net>
2014-05-02 11:12 ` [patch 1/6] preempt_lazy: remove redundant test_thread_flag() call Mike Galbraith
2014-05-06 2:37 ` Steven Rostedt
2014-05-06 5:33 ` Mike Galbraith
2014-05-09 13:17 ` Sebastian Andrzej Siewior
2014-05-02 11:12 ` Mike Galbraith [this message]
2014-05-02 11:13 ` [patch 3/6] stomp-machine: fix typo in kernel/cpu.c Mike Galbraith
2014-05-02 11:13 ` [patch 4/6] stomp-machine: fix typo in kernel/stop_machine.c Mike Galbraith
2014-05-02 11:13 ` [patch 5/6] stomp-machine: create lg_global_trylock_relax() primitive Mike Galbraith
2014-05-02 11:13 ` [patch 6/6] stomp-machine: use lg_global_trylock_relax() to dead with stop_cpus_lock lglock Mike Galbraith
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