The patch titled
uml: eliminate interrupts in the idle loop
has been added to the -mm tree. Its filename is
uml-eliminate-interrupts-in-the-idle-loop.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: uml: eliminate interrupts in the idle loop
From: Jeff Dike <[EMAIL PROTECTED]>
Now, the idle loop now longer needs SIGALRM firing - it can just sleep for the
requisite amount of time and fake a timer interrupt when it finishes.
Any use of ITIMER_REAL now goes away. disable_timer only turns off
ITIMER_VIRTUAL. switch_timers is no longer needed, so it, and all calls, goes
away.
disable_timer now returns the amount of time remaining on the timer.
default_idle uses this to tell idle_sleep how long to sleep. idle_sleep will
call alarm_handler if nanosleep returns 0, which is the case if it didn't
return early due to an interrupt. Otherwise, it just returns.
Signed-off-by: Jeff Dike <[EMAIL PROTECTED]>
Cc: Thomas Gleixner <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
arch/um/include/os.h | 5 +--
arch/um/kernel/process.c | 7 ++--
arch/um/os-Linux/signal.c | 3 --
arch/um/os-Linux/time.c | 54 +++++++-----------------------------
4 files changed, 17 insertions(+), 52 deletions(-)
diff -puN arch/um/include/os.h~uml-eliminate-interrupts-in-the-idle-loop
arch/um/include/os.h
--- a/arch/um/include/os.h~uml-eliminate-interrupts-in-the-idle-loop
+++ a/arch/um/include/os.h
@@ -251,11 +251,10 @@ extern void os_dump_core(void);
/* time.c */
#define BILLION (1000 * 1000 * 1000)
-extern int switch_timers(int to_real);
-extern void idle_sleep(int secs);
+extern void idle_sleep(unsigned long long nsecs);
extern int set_interval(void);
extern int timer_one_shot(int ticks);
-extern void disable_timer(void);
+extern unsigned long long disable_timer(void);
extern void uml_idle_timer(void);
extern unsigned long long os_nsecs(void);
diff -puN arch/um/kernel/process.c~uml-eliminate-interrupts-in-the-idle-loop
arch/um/kernel/process.c
--- a/arch/um/kernel/process.c~uml-eliminate-interrupts-in-the-idle-loop
+++ a/arch/um/kernel/process.c
@@ -235,6 +235,8 @@ void initial_thread_cb(void (*proc)(void
void default_idle(void)
{
+ unsigned long long nsecs;
+
while(1) {
/* endless idle loop with no priority at all */
@@ -246,9 +248,8 @@ void default_idle(void)
schedule();
tick_nohz_stop_sched_tick();
- switch_timers(1);
- idle_sleep(10);
- switch_timers(0);
+ nsecs = disable_timer();
+ idle_sleep(nsecs);
tick_nohz_restart_sched_tick();
}
}
diff -puN arch/um/os-Linux/signal.c~uml-eliminate-interrupts-in-the-idle-loop
arch/um/os-Linux/signal.c
--- a/arch/um/os-Linux/signal.c~uml-eliminate-interrupts-in-the-idle-loop
+++ a/arch/um/os-Linux/signal.c
@@ -120,7 +120,6 @@ void (*handlers[_NSIG])(int sig, struct
void handle_signal(int sig, struct sigcontext *sc)
{
unsigned long pending = 1UL << sig;
- int timer = switch_timers(0);
do {
int nested, bail;
@@ -157,8 +156,6 @@ void handle_signal(int sig, struct sigco
if (!nested)
pending = from_irq_stack(nested);
} while (pending);
-
- switch_timers(timer);
}
extern void hard_handler(int sig);
diff -puN arch/um/os-Linux/time.c~uml-eliminate-interrupts-in-the-idle-loop
arch/um/os-Linux/time.c
--- a/arch/um/os-Linux/time.c~uml-eliminate-interrupts-in-the-idle-loop
+++ a/arch/um/os-Linux/time.c
@@ -12,8 +12,6 @@
#include "os.h"
#include "user.h"
-static int is_real_timer = 0;
-
int set_interval(void)
{
int usec = 1000000/UM_HZ;
@@ -53,47 +51,15 @@ static inline unsigned long long tv_to_n
tv->tv_usec * 1000;
}
-void disable_timer(void)
+unsigned long long disable_timer(void)
{
- struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
+ struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });
- if ((setitimer(ITIMER_VIRTUAL, &disable, NULL) < 0) ||
- (setitimer(ITIMER_REAL, &disable, NULL) < 0))
+ if(setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
printk(UM_KERN_ERR "disable_timer - setitimer failed, "
"errno = %d\n", errno);
-}
-
-int switch_timers(int to_real)
-{
- struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
- struct itimerval enable;
- int old, new, old_type = is_real_timer;
-
- if(to_real == old_type)
- return to_real;
-
- if (to_real) {
- old = ITIMER_VIRTUAL;
- new = ITIMER_REAL;
- }
- else {
- old = ITIMER_REAL;
- new = ITIMER_VIRTUAL;
- }
-
- if (setitimer(old, &disable, &enable) < 0)
- printk(UM_KERN_ERR "switch_timers - setitimer disable failed, "
- "errno = %d\n", errno);
-
- if((enable.it_value.tv_sec == 0) && (enable.it_value.tv_usec == 0))
- enable.it_value = enable.it_interval;
- if (setitimer(new, &enable, NULL))
- printk(UM_KERN_ERR "switch_timers - setitimer enable failed, "
- "errno = %d\n", errno);
-
- is_real_timer = to_real;
- return old_type;
+ return tv_to_nsec(&time.it_value);
}
unsigned long long os_nsecs(void)
@@ -104,11 +70,13 @@ unsigned long long os_nsecs(void)
return tv_to_nsec(&tv);
}
-void idle_sleep(int secs)
+extern void alarm_handler(int sig, struct sigcontext *sc);
+
+void idle_sleep(unsigned long long nsecs)
{
- struct timespec ts;
+ struct timespec ts = { .tv_sec = nsecs / BILLION,
+ .tv_nsec = nsecs % BILLION };
- ts.tv_sec = secs;
- ts.tv_nsec = 0;
- nanosleep(&ts, NULL);
+ if (nanosleep(&ts, &ts) == 0)
+ alarm_handler(SIGVTALRM, NULL);
}
_
Patches currently in -mm which might be from [EMAIL PROTECTED] are
git-kvm.patch
hostfs-convert-to-new-aops.patch
uml-move-userspace-code-to-userspace-file.patch
uml-tidy-recently-moved-code.patch
uml-fix-error-cleanup-ordering.patch
uml-console-subsystem-tidying.patch
uml-fix-console-writing-bugs.patch
uml-console-tidying.patch
uml-stop-using-libc-asm-pageh.patch
uml-fix-an-ipv6-libc-vs-kernel-symbol-clash.patch
uml-fix-nonremovability-of-watchdog.patch
uml-stop-specially-protecting-kernel-stacks.patch
uml-stop-saving-process-fp-state.patch
uml-stop-saving-process-fp-state-fix.patch
uml-physmem-code-tidying.patch
uml-add-vde-networking-support.patch
uml-remove-unnecessary-hostfs_getattr.patch
uml-throw-out-config_mode_tt.patch
uml-remove-sysdep-threadh.patch
uml-style-fixes-pass-1.patch
uml-throw-out-choose_mode.patch
uml-style-fixes-pass-2.patch
uml-remove-code-made-redundant-by-choose_mode-removal.patch
uml-style-fixes-pass-3.patch
uml-remove-__u64-usage-from-physical-memory-subsystem.patch
uml-get-rid-of-do_longjmp.patch
uml-fold-mmu_context_skas-into-mm_context.patch
uml-rename-pt_regs-general-purpose-register-file.patch
uml-rename-pt_regs-general-purpose-register-file-fix.patch
uml-free-ldt-state-on-process-exit.patch
uml-remove-os_-usage-from-userspace-files.patch
uml-replace-clone-with-fork.patch
uml-fix-inlines.patch
uml-userspace-files-should-call-libc-directly.patch
uml-clean-up-tlb-flush-path.patch
uml-remove-unneeded-if-from-hostfs.patch
uml-fix-hostfs-style.patch
uml-dont-use-glibc-asm-userh.patch
uml-floating-point-signal-delivery-fixes.patch
uml-ptrace-floating-point-fixes.patch
uml-coredumping-floating-point-fixes.patch
uml-sysrq-and-mconsole-fixes.patch
uml-style-fixes-in-fp-code.patch
uml-eliminate-floating-point-state-from-register-file.patch
uml-remove-unused-file.patch
uml-more-idiomatic-parameter-parsing.patch
uml-eliminate-hz.patch
uml-fix-timer-switching.patch
uml-simplify-interval-setting.patch
uml-separate-timer-initialization.patch
uml-generic_time-support.patch
uml-generic_clockevents-support.patch
uml-clocksource-support.patch
uml-tickless-support.patch
uml-eliminate-interrupts-in-the-idle-loop.patch
uml-eliminate-sigalrm.patch
uml-use-sec_per_sec-constants.patch
bitops-introduce-lock-ops.patch
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