Subject: + wait-introduce-wait_event_commonwq-condition-state-timeout.patch added to -mm tree
To: oleg@xxxxxxxxxx,daniel.vetter@xxxxxxxx,imre.deak@xxxxxxxxx,lczerner@xxxxxxxxxx,tj@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 10 Jun 2013 16:13:25 -0700
The patch titled
Subject: wait: introduce wait_event_common(wq, condition, state, timeout)
has been added to the -mm tree. Its filename is
wait-introduce-wait_event_commonwq-condition-state-timeout.patch
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From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: wait: introduce wait_event_common(wq, condition, state, timeout)
To remind, I think that 4c663cfc "wait: fix false timeouts when using
wait_event_timeout()" is not enough, wait(wq, true, 0) still returns zero.
But to me the main problem is that wait_event* macros duplicate the same
code again and again. Imho it would be nice to create a single helper.
To simplify the review, this is the code after 1/2:
#define __wait_no_timeout(tout) \
(__builtin_constant_p(tout) && (tout) == MAX_SCHEDULE_TIMEOUT)
/* uglified signal_pending_state() optimized for constant state */
#define __wait_signal_pending(state) \
((state == TASK_INTERRUPTIBLE) ? signal_pending(current) : \
(state == TASK_KILLABLE) ? fatal_signal_pending(current) : \
0)
#define __wait_event_common(wq, condition, state, tout) \
({ \
DEFINE_WAIT(__wait); \
long __ret = 0, __tout = tout; \
\
for (;;) { \
prepare_to_wait(&wq, &__wait, state); \
if (condition) { \
__ret = __wait_no_timeout(tout) ?: __tout ?: 1; \
break; \
} \
\
if (__wait_signal_pending(state)) { \
__ret = -ERESTARTSYS; \
break; \
} \
\
if (__wait_no_timeout(tout)) \
schedule(); \
else if (__tout) \
__tout = schedule_timeout(__tout); \
else \
break; \
} \
finish_wait(&wq, &__wait); \
__ret; \
})
#define wait_event_common(wq, condition, state, tout) \
({ \
long __ret; \
if (condition) \
__ret = __wait_no_timeout(tout) ?: (tout) ?: 1; \
else \
__ret = __wait_event_common(wq, condition, state, tout);\
__ret; \
})
2/2 doesn't look like a cleanup. But personally I think that it makes
sense to shrink .text,
- 4977769 2930984 10104832 18013585 112dd91 vmlinux
+ 4976847 2930984 10104832 18012663 112d9f7 vmlinux
on my build.
This patch:
1. wait_event_timeout(wq, true, 0) returns zero, I think this is
wrong and should be fixed.
__wait_event_timeout() was already changed by 4c663cfc but we
need the same logic in wait_event_timeout() if the fast-path
check succeeds.
2. wait_event_timeout/__wait_event_timeout interface do not match
wait_event(), you can't use __wait_event_timeout() instead of
wait_event_timeout() if you do not need the fast-path check.
3. wait_event_* macros duplicate the same code.
This patch adds a single helper wait_event_common() which hopefully
does everything right. Compiler optimizes out the "dead" code when
we do not need signal_pending/schedule_timeout.
With this patch "size vmlinux" reports that .text/data shrinks but
I think this depends on gcc/config.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reviewed-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Cc: Lukas Czerner <lczerner@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/wait.h | 181 +++++++++++++++--------------------------
1 file changed, 70 insertions(+), 111 deletions(-)
diff -puN include/linux/wait.h~wait-introduce-wait_event_commonwq-condition-state-timeout include/linux/wait.h
--- a/include/linux/wait.h~wait-introduce-wait_event_commonwq-condition-state-timeout
+++ a/include/linux/wait.h
@@ -179,18 +179,52 @@ wait_queue_head_t *bit_waitqueue(void *,
#define wake_up_interruptible_sync_poll(x, m) \
__wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
-#define __wait_event(wq, condition) \
-do { \
+#define __wait_no_timeout(tout) \
+ (__builtin_constant_p(tout) && (tout) == MAX_SCHEDULE_TIMEOUT)
+
+/* uglified signal_pending_state() optimized for constant state */
+#define __wait_signal_pending(state) \
+ ((state == TASK_INTERRUPTIBLE) ? signal_pending(current) : \
+ (state == TASK_KILLABLE) ? fatal_signal_pending(current) : \
+ 0)
+
+#define __wait_event_common(wq, condition, state, tout) \
+({ \
DEFINE_WAIT(__wait); \
+ long __ret = 0, __tout = tout; \
\
for (;;) { \
- prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
- if (condition) \
+ prepare_to_wait(&wq, &__wait, state); \
+ if (condition) { \
+ __ret = __wait_no_timeout(tout) ?: __tout ?: 1; \
+ break; \
+ } \
+ \
+ if (__wait_signal_pending(state)) { \
+ __ret = -ERESTARTSYS; \
+ break; \
+ } \
+ \
+ if (__wait_no_timeout(tout)) \
+ schedule(); \
+ else if (__tout) \
+ __tout = schedule_timeout(__tout); \
+ else \
break; \
- schedule(); \
} \
finish_wait(&wq, &__wait); \
-} while (0)
+ __ret; \
+})
+
+#define wait_event_common(wq, condition, state, tout) \
+({ \
+ long __ret; \
+ if (condition) \
+ __ret = __wait_no_timeout(tout) ?: (tout) ?: 1; \
+ else \
+ __ret = __wait_event_common(wq, condition, state, tout);\
+ __ret; \
+})
/**
* wait_event - sleep until a condition gets true
@@ -204,29 +238,13 @@ do { \
* wake_up() has to be called after changing any variable that could
* change the result of the wait condition.
*/
-#define wait_event(wq, condition) \
-do { \
- if (condition) \
- break; \
- __wait_event(wq, condition); \
-} while (0)
+#define __wait_event(wq, condition) \
+ __wait_event_common(wq, condition, \
+ TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT) \
-#define __wait_event_timeout(wq, condition, ret) \
-do { \
- DEFINE_WAIT(__wait); \
- \
- for (;;) { \
- prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
- if (condition) \
- break; \
- ret = schedule_timeout(ret); \
- if (!ret) \
- break; \
- } \
- if (!ret && (condition)) \
- ret = 1; \
- finish_wait(&wq, &__wait); \
-} while (0)
+#define wait_event(wq, condition) \
+ wait_event_common(wq, condition, \
+ TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT) \
/**
* wait_event_timeout - sleep until a condition gets true or a timeout elapses
@@ -245,31 +263,13 @@ do { \
* jiffies (at least 1) if the @condition evaluated to %true before
* the @timeout elapsed.
*/
-#define wait_event_timeout(wq, condition, timeout) \
-({ \
- long __ret = timeout; \
- if (!(condition)) \
- __wait_event_timeout(wq, condition, __ret); \
- __ret; \
-})
+#define __wait_event_timeout(wq, condition, timeout) \
+ __wait_event_common(wq, condition, \
+ TASK_UNINTERRUPTIBLE, timeout)
-#define __wait_event_interruptible(wq, condition, ret) \
-do { \
- DEFINE_WAIT(__wait); \
- \
- for (;;) { \
- prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
- if (condition) \
- break; \
- if (!signal_pending(current)) { \
- schedule(); \
- continue; \
- } \
- ret = -ERESTARTSYS; \
- break; \
- } \
- finish_wait(&wq, &__wait); \
-} while (0)
+#define wait_event_timeout(wq, condition, timeout) \
+ wait_event_common(wq, condition, \
+ TASK_UNINTERRUPTIBLE, timeout)
/**
* wait_event_interruptible - sleep until a condition gets true
@@ -286,35 +286,13 @@ do { \
* The function will return -ERESTARTSYS if it was interrupted by a
* signal and 0 if @condition evaluated to true.
*/
-#define wait_event_interruptible(wq, condition) \
-({ \
- int __ret = 0; \
- if (!(condition)) \
- __wait_event_interruptible(wq, condition, __ret); \
- __ret; \
-})
+#define __wait_event_interruptible(wq, condition) \
+ __wait_event_common(wq, condition, \
+ TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT)
-#define __wait_event_interruptible_timeout(wq, condition, ret) \
-do { \
- DEFINE_WAIT(__wait); \
- \
- for (;;) { \
- prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
- if (condition) \
- break; \
- if (!signal_pending(current)) { \
- ret = schedule_timeout(ret); \
- if (!ret) \
- break; \
- continue; \
- } \
- ret = -ERESTARTSYS; \
- break; \
- } \
- if (!ret && (condition)) \
- ret = 1; \
- finish_wait(&wq, &__wait); \
-} while (0)
+#define wait_event_interruptible(wq, condition) \
+ wait_event_common(wq, condition, \
+ TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT)
/**
* wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
@@ -334,13 +312,13 @@ do { \
* a signal, or the remaining jiffies (at least 1) if the @condition
* evaluated to %true before the @timeout elapsed.
*/
+#define __wait_event_interruptible_timeout(wq, condition, timeout) \
+ __wait_event_common(wq, condition, \
+ TASK_INTERRUPTIBLE, timeout)
+
#define wait_event_interruptible_timeout(wq, condition, timeout) \
-({ \
- long __ret = timeout; \
- if (!(condition)) \
- __wait_event_interruptible_timeout(wq, condition, __ret); \
- __ret; \
-})
+ wait_event_common(wq, condition, \
+ TASK_INTERRUPTIBLE, timeout)
#define __wait_event_hrtimeout(wq, condition, timeout, state) \
({ \
@@ -607,24 +585,6 @@ do { \
-#define __wait_event_killable(wq, condition, ret) \
-do { \
- DEFINE_WAIT(__wait); \
- \
- for (;;) { \
- prepare_to_wait(&wq, &__wait, TASK_KILLABLE); \
- if (condition) \
- break; \
- if (!fatal_signal_pending(current)) { \
- schedule(); \
- continue; \
- } \
- ret = -ERESTARTSYS; \
- break; \
- } \
- finish_wait(&wq, &__wait); \
-} while (0)
-
/**
* wait_event_killable - sleep until a condition gets true
* @wq: the waitqueue to wait on
@@ -640,14 +600,13 @@ do { \
* The function will return -ERESTARTSYS if it was interrupted by a
* signal and 0 if @condition evaluated to true.
*/
-#define wait_event_killable(wq, condition) \
-({ \
- int __ret = 0; \
- if (!(condition)) \
- __wait_event_killable(wq, condition, __ret); \
- __ret; \
-})
+#define __wait_event_killable(wq, condition) \
+ __wait_event_common(wq, condition, \
+ TASK_KILLABLE, MAX_SCHEDULE_TIMEOUT)
+#define wait_event_killable(wq, condition) \
+ wait_event_common(wq, condition, \
+ TASK_KILLABLE, MAX_SCHEDULE_TIMEOUT)
#define __wait_event_lock_irq(wq, condition, lock, cmd) \
do { \
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
linux-next.patch
audit-wait_for_auditd-should-use-task_uninterruptible.patch
posix_cpu_timer-consolidate-expiry-time-type.patch
posix_cpu_timers-consolidate-timer-list-cleanups.patch
posix_cpu_timers-consolidate-expired-timers-check.patch
posix-timers-correctly-get-dying-task-time-sample-in-posix_cpu_timer_schedule.patch
posix_timers-fix-racy-timer-delta-caching-on-task-exit.patch
include-linux-schedh-dont-use-task-pid-tgid-in-same_thread_group-has_group_leader_pid.patch
lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-powerpc-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-arm-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-sh-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-revert-prepare-to-fix-racy-accesses-on-task-breakpoints.patch
ptrace-x86-simplify-the-disable-logic-in-ptrace_write_dr7.patch
ptrace-x86-dont-delay-disable-till-second-pass-in-ptrace_write_dr7.patch
ptrace-x86-introduce-ptrace_register_breakpoint.patch
ptrace-x86-ptrace_write_dr7-should-create-bp-if-disabled.patch
ptrace-x86-cleanup-ptrace_set_debugreg.patch
ptrace-ptrace_detach-should-do-flush_ptrace_hw_breakpointchild.patch
ptrace-x86-flush_ptrace_hw_breakpoint-shoule-clear-the-virtual-debug-registers.patch
x86-kill-tif_debug.patch
ptrace-add-ability-to-get-set-signal-blocked-mask.patch
usermodehelper-kill-the-sub_info-path-check.patch
coredump-format_corename-can-leak-cn-corename.patch
coredump-introduce-cn_vprintf.patch
coredump-cn_vprintf-has-no-reason-to-call-vsnprintf-twice.patch
coredump-kill-cn_escape-introduce-cn_esc_printf.patch
coredump-kill-call_count-add-core_name_size.patch
coredump-%-at-the-end-shouldnt-bypass-core_uses_pid-logic.patch
coredump-%-at-the-end-shouldnt-bypass-core_uses_pid-logic-fix.patch
fs-execc-do_execve_common-use-current_user.patch
wait-introduce-wait_event_commonwq-condition-state-timeout.patch
wait-introduce-prepare_to_wait_event.patch
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