* [PATCH] TASK_KILLABLE version 2
@ 2007-09-02 2:43 Matthew Wilcox
2007-09-02 2:46 ` [PATCH 1/5] Use wake_up_locked() in eventpoll Matthew Wilcox
` (5 more replies)
0 siblings, 6 replies; 23+ messages in thread
From: Matthew Wilcox @ 2007-09-02 2:43 UTC (permalink / raw)
To: Andrew Morton, Linus Torvalds; +Cc: linux-kernel
Here's the second version of TASK_KILLABLE. A few changes since version 1:
- Don't split up TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE.
TASK_WAKESIGNAL and TASK_LOADAVG were pretty much equivalent, and since
we had to keep __TASK_{UN,}INTERRUPTIBLE anyway, splitting them made
little sense.
- Instead, I've added some is_task_*() predicates. I think they
achieve what Linus wanted without consuming flag bits and without
checking a metric tonne of code to see whether it wanted
TASK_UNINTERRUPTIBLE or __TASK_UNINTERRUPTIBLE.
- Renamed try_lock_page() to lock_page_killable() and change the sense.
I had envisioned uses being like spin_trylock(), but that turned out
not to make sense.
- Fix the bug Trond noticed in wait_on_retry_sync_kiocb() by having the
callers handle it returning -EINTR
- Fix the bug I noticed in sync_pages_killable() by adding the new
function fatal_signal_pending()
- Audit a lot of uses of TASK_*. A few seemed dubious and were fixed.
I'd like to see this spend a bit of time in the -mm tree. I've wasted
a couple of days trying to track down why my machine no longer does
much after starting init, so clearly I'm tampering with stuff I don't
quite understand.
Having said that, I ditched that version of the code and started again
with a much more minimalist approach. I've also split the patch into
five independent pieces, each of which accomplishes a logical step,
for ease of bisection.
I think patch 1/5 is clearly Right and should be merged ASAP. Patch 2/5
and 3/5 carry some risk. 4/5 and 5/5 seem less risky to me (and are
independent of each other; both rely on 1-3 being applied first)
I obviously haven't covered every place that can result in a process
sleeping uninterruptibly while attempting an operation. But sync_page
(patch 4/5) covers about 90% of the times I've attempted to kill cat,
and I hope that by providing the two examples, I can help other people
to fix the cases that they find interesting.
--
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
^ permalink raw reply [flat|nested] 23+ messages in thread* [PATCH 1/5] Use wake_up_locked() in eventpoll 2007-09-02 2:43 [PATCH] TASK_KILLABLE version 2 Matthew Wilcox @ 2007-09-02 2:46 ` Matthew Wilcox 2007-09-02 2:46 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox ` (4 subsequent siblings) 5 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-02 2:46 UTC (permalink / raw) To: akpm, torvalds; +Cc: linux-kernel, Matthew Wilcox Replace the uses of __wake_up_locked with wake_up_locked Signed-off-by: Matthew Wilcox <matthew@wil.cx> --- fs/eventpoll.c | 11 ++++------- 1 files changed, 4 insertions(+), 7 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 77b9953..72e4cb4 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -657,8 +657,7 @@ is_linked: * wait list. */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | - TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; @@ -781,7 +780,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, /* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } @@ -855,8 +854,7 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even /* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | - TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } @@ -979,8 +977,7 @@ errxit: * wait list (delayed after we release the lock). */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | - TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 2/5] Use macros instead of TASK_ flags 2007-09-02 2:43 [PATCH] TASK_KILLABLE version 2 Matthew Wilcox 2007-09-02 2:46 ` [PATCH 1/5] Use wake_up_locked() in eventpoll Matthew Wilcox @ 2007-09-02 2:46 ` Matthew Wilcox 2007-09-02 2:54 ` Matthew Wilcox ` (2 more replies) 2007-09-02 2:46 ` [PATCH 3/5] Add TASK_WAKEKILL Matthew Wilcox ` (3 subsequent siblings) 5 siblings, 3 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-02 2:46 UTC (permalink / raw) To: akpm, torvalds; +Cc: linux-kernel, Matthew Wilcox Abstracting away direct uses of TASK_ flags allows us to change the definitions of the task flags more easily. Also restructure do_wait() a little Signed-off-by: Matthew Wilcox <matthew@wil.cx> --- arch/ia64/kernel/perfmon.c | 4 +- fs/proc/array.c | 9 +--- fs/proc/base.c | 2 +- include/linux/sched.h | 15 +++++++ include/linux/wait.h | 11 +++-- kernel/exit.c | 90 +++++++++++++++++++------------------------ kernel/power/process.c | 7 +-- kernel/ptrace.c | 8 ++-- kernel/sched.c | 15 +++---- kernel/signal.c | 6 +- kernel/wait.c | 2 +- 11 files changed, 83 insertions(+), 86 deletions(-) diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c index 14b8e5a..75a99ee 100644 --- a/arch/ia64/kernel/perfmon.c +++ b/arch/ia64/kernel/perfmon.c @@ -2637,7 +2637,7 @@ pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task) */ if (task == current) return 0; - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task->state)) { DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task->pid, task->state)); return -EBUSY; } @@ -4797,7 +4797,7 @@ recheck: * the task must be stopped. */ if (PFM_CMD_STOPPED(cmd)) { - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task)) { DPRINT(("[%d] task not in stopped state\n", task->pid)); return -EBUSY; } diff --git a/fs/proc/array.c b/fs/proc/array.c index ee4814d..6a3c876 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -140,13 +140,8 @@ static const char *task_state_array[] = { static inline const char *get_task_state(struct task_struct *tsk) { - unsigned int state = (tsk->state & (TASK_RUNNING | - TASK_INTERRUPTIBLE | - TASK_UNINTERRUPTIBLE | - TASK_STOPPED | - TASK_TRACED)) | - (tsk->exit_state & (EXIT_ZOMBIE | - EXIT_DEAD)); + unsigned int state = (tsk->state & TASK_REPORT) | + (tsk->exit_state & (EXIT_ZOMBIE | EXIT_DEAD)); const char **p = &task_state_array[0]; while (state) { diff --git a/fs/proc/base.c b/fs/proc/base.c index 19489b0..3155ef1 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -196,7 +196,7 @@ static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vf (task == current || \ (task->parent == current && \ (task->ptrace & PT_PTRACED) && \ - (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \ + (is_task_stopped_or_traced(task)) && \ security_ptrace(current,task) == 0)) static int proc_pid_environ(struct task_struct *task, char * buffer) diff --git a/include/linux/sched.h b/include/linux/sched.h index f4e324e..ea509e9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -176,6 +176,21 @@ print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) #define TASK_NONINTERACTIVE 64 #define TASK_DEAD 128 +/* Convenience macros for the sake of wake_up */ +#define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) +#define TASK_ALL (TASK_NORMAL | TASK_STOPPED | TASK_TRACED) + +/* get_task_state() */ +#define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \ + TASK_UNINTERRUPTIBLE | TASK_STOPPED | \ + TASK_TRACED) + +#define is_task_traced(task) ((task->state & TASK_TRACED) != 0) +#define is_task_stopped(task) ((task->state & TASK_STOPPED) != 0) +#define is_task_stopped_or_traced(task) \ + ((task->state & (TASK_STOPPED | TASK_TRACED)) != 0) +#define is_task_loadavg(task) ((task->state & TASK_UNINTERRUPTIBLE) != 0) + #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) #define set_task_state(tsk, state_value) \ diff --git a/include/linux/wait.h b/include/linux/wait.h index 0e68628..0a410a4 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -152,14 +152,15 @@ int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned)); int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned)); wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int)); -#define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL) -#define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL) -#define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL) +#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) +#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) +#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL) +#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL) + #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL) #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL) #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL) -#define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE) -#define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1) +#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1) #define __wait_event(wq, condition) \ do { \ diff --git a/kernel/exit.c b/kernel/exit.c index 06b24b3..3abc703 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -259,7 +259,7 @@ static int has_stopped_jobs(struct pid *pgrp) struct task_struct *p; do_each_pid_task(pgrp, PIDTYPE_PGID, p) { - if (p->state != TASK_STOPPED) + if (is_task_stopped(p)) continue; retval = 1; break; @@ -634,7 +634,7 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) p->parent = p->real_parent; add_parent(p); - if (p->state == TASK_TRACED) { + if (is_task_traced(p)) { /* * If it was at a trace stop, turn it into * a normal stop since it's no longer being @@ -1372,7 +1372,7 @@ static int wait_task_stopped(struct task_struct *p, int delayed_group_leader, exit_code = p->exit_code; if (unlikely(!exit_code) || - unlikely(p->state & TASK_TRACED)) + unlikely(is_task_traced(p))) goto bail_ref; return wait_noreap_copyout(p, pid, uid, why, (exit_code << 8) | 0x7f, @@ -1554,60 +1554,51 @@ repeat: } allowed = 1; - switch (p->state) { - case TASK_TRACED: - /* - * When we hit the race with PTRACE_ATTACH, - * we will not report this child. But the - * race means it has not yet been moved to - * our ptrace_children list, so we need to - * set the flag here to avoid a spurious ECHILD - * when the race happens with the only child. - */ - flag = 1; - if (!my_ptrace_child(p)) - continue; - /*FALLTHROUGH*/ - case TASK_STOPPED: + if (is_task_stopped_or_traced(p)) { /* * It's stopped now, so it might later * continue, exit, or stop again. + * + * When we hit the race with PTRACE_ATTACH, we + * will not report this child. But the race + * means it has not yet been moved to our + * ptrace_children list, so we need to set the + * flag here to avoid a spurious ECHILD when + * the race happens with the only child. */ flag = 1; - if (!(options & WUNTRACED) && - !my_ptrace_child(p)) - continue; + + if (!my_ptrace_child(p)) { + if (is_task_traced(p)) + continue; + if (!(options & WUNTRACED)) + continue; + } + retval = wait_task_stopped(p, ret == 2, - (options & WNOWAIT), - infop, - stat_addr, ru); + (options & WNOWAIT), infop, + stat_addr, ru); if (retval == -EAGAIN) goto repeat; if (retval != 0) /* He released the lock. */ goto end; - break; - default: - // case EXIT_DEAD: - if (p->exit_state == EXIT_DEAD) + } else if (p->exit_state == EXIT_DEAD) { + continue; + } else if (p->exit_state == EXIT_ZOMBIE) { + /* + * Eligible but we cannot release it yet: + */ + if (ret == 2) + goto check_continued; + if (!likely(options & WEXITED)) continue; - // case EXIT_ZOMBIE: - if (p->exit_state == EXIT_ZOMBIE) { - /* - * Eligible but we cannot release - * it yet: - */ - if (ret == 2) - goto check_continued; - if (!likely(options & WEXITED)) - continue; - retval = wait_task_zombie( - p, (options & WNOWAIT), - infop, stat_addr, ru); - /* He released the lock. */ - if (retval != 0) - goto end; - break; - } + retval = wait_task_zombie(p, + (options & WNOWAIT), infop, + stat_addr, ru); + /* He released the lock. */ + if (retval != 0) + goto end; + } else { check_continued: /* * It's running now, so it might later @@ -1616,12 +1607,11 @@ check_continued: flag = 1; if (!unlikely(options & WCONTINUED)) continue; - retval = wait_task_continued( - p, (options & WNOWAIT), - infop, stat_addr, ru); + retval = wait_task_continued(p, + (options & WNOWAIT), infop, + stat_addr, ru); if (retval != 0) /* He released the lock. */ goto end; - break; } } if (!flag) { diff --git a/kernel/power/process.c b/kernel/power/process.c index 3434940..ac0c27a 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -83,10 +83,10 @@ static void freeze_task(struct task_struct *p) rmb(); if (!frozen(p)) { set_freeze_flag(p); - if (p->state == TASK_STOPPED) + if (is_task_stopped(p)) force_sig_specific(SIGSTOP, p); spin_lock_irqsave(&p->sighand->siglock, flags); - signal_wake_up(p, p->state == TASK_STOPPED); + signal_wake_up(p, is_task_stopped(p)); spin_unlock_irqrestore(&p->sighand->siglock, flags); } } @@ -120,8 +120,7 @@ static int try_to_freeze_tasks(int freeze_user_space) continue; if (freeze_user_space) { - if (p->state == TASK_TRACED && - frozen(p->parent)) { + if (is_task_traced(p) && frozen(p->parent)) { cancel_freezing(p); continue; } diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 82a558b..92a2283 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -50,7 +50,7 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) void ptrace_untrace(struct task_struct *child) { spin_lock(&child->sighand->siglock); - if (child->state == TASK_TRACED) { + if (is_task_traced(child)) { if (child->signal->flags & SIGNAL_STOP_STOPPED) { child->state = TASK_STOPPED; } else { @@ -78,7 +78,7 @@ void __ptrace_unlink(struct task_struct *child) add_parent(child); } - if (child->state == TASK_TRACED) + if (is_task_traced(child)) ptrace_untrace(child); } @@ -102,9 +102,9 @@ int ptrace_check_attach(struct task_struct *child, int kill) && child->signal != NULL) { ret = 0; spin_lock_irq(&child->sighand->siglock); - if (child->state == TASK_STOPPED) { + if (is_task_stopped(child)) { child->state = TASK_TRACED; - } else if (child->state != TASK_TRACED && !kill) { + } else if (!is_task_traced(child) && !kill) { ret = -ESRCH; } spin_unlock_irq(&child->sighand->siglock); diff --git a/kernel/sched.c b/kernel/sched.c index b533d6d..e3be352 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -944,7 +944,7 @@ static int effective_prio(struct task_struct *p) */ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, wakeup); @@ -958,7 +958,7 @@ static inline void activate_idle_task(struct task_struct *p, struct rq *rq) { update_rq_clock(rq); - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, 0); @@ -970,7 +970,7 @@ static inline void activate_idle_task(struct task_struct *p, struct rq *rq) */ static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible++; dequeue_task(rq, p, sleep); @@ -1566,8 +1566,7 @@ out: int fastcall wake_up_process(struct task_struct *p) { - return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | - TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); + return try_to_wake_up(p, TASK_ALL, 0); } EXPORT_SYMBOL(wake_up_process); @@ -3708,8 +3707,7 @@ void fastcall complete(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done++; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 1, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete); @@ -3720,8 +3718,7 @@ void fastcall complete_all(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done += UINT_MAX/2; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 0, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete_all); diff --git a/kernel/signal.c b/kernel/signal.c index 3169bed..53cbac4 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -841,7 +841,7 @@ static inline int wants_signal(int sig, struct task_struct *p) return 0; if (sig == SIGKILL) return 1; - if (p->state & (TASK_STOPPED | TASK_TRACED)) + if (is_task_stopped_or_traced(p)) return 0; return task_curr(p) || !signal_pending(p); } @@ -1445,7 +1445,7 @@ void do_notify_parent(struct task_struct *tsk, int sig) BUG_ON(sig == -1); /* do_notify_parent_cldstop should have been called instead. */ - BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); + BUG_ON(is_task_stopped_or_traced(tsk)); BUG_ON(!tsk->ptrace && (tsk->group_leader != tsk || !thread_group_empty(tsk))); @@ -1712,7 +1712,7 @@ static int do_signal_stop(int signr) * so this check has no races. */ if (!t->exit_state && - !(t->state & (TASK_STOPPED|TASK_TRACED))) { + !is_task_stopped_or_traced(t)) { stop_count++; signal_wake_up(t, 0); } diff --git a/kernel/wait.c b/kernel/wait.c index 444ddbf..f987688 100644 --- a/kernel/wait.c +++ b/kernel/wait.c @@ -215,7 +215,7 @@ void fastcall __wake_up_bit(wait_queue_head_t *wq, void *word, int bit) { struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit); if (waitqueue_active(wq)) - __wake_up(wq, TASK_INTERRUPTIBLE|TASK_UNINTERRUPTIBLE, 1, &key); + __wake_up(wq, TASK_NORMAL, 1, &key); } EXPORT_SYMBOL(__wake_up_bit); -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-09-02 2:46 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox @ 2007-09-02 2:54 ` Matthew Wilcox 2007-09-02 3:35 ` Daniel Walker 2007-09-03 21:03 ` Matthew Wilcox 2 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-02 2:54 UTC (permalink / raw) To: akpm, torvalds; +Cc: linux-kernel On Sat, Sep 01, 2007 at 10:46:51PM -0400, Matthew Wilcox wrote: > Abstracting away direct uses of TASK_ flags allows us to change the > definitions of the task flags more easily. > --- a/kernel/exit.c > +++ b/kernel/exit.c > @@ -259,7 +259,7 @@ static int has_stopped_jobs(struct pid *pgrp) > struct task_struct *p; > > do_each_pid_task(pgrp, PIDTYPE_PGID, p) { > - if (p->state != TASK_STOPPED) > + if (is_task_stopped(p)) Funny how I can't spot these things before I send them. Fixed locally; I'll see if anyone else spots a problem before I send out a v3. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-09-02 2:46 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 2007-09-02 2:54 ` Matthew Wilcox @ 2007-09-02 3:35 ` Daniel Walker 2007-09-02 4:05 ` Matthew Wilcox 2007-09-03 21:03 ` Matthew Wilcox 2 siblings, 1 reply; 23+ messages in thread From: Daniel Walker @ 2007-09-02 3:35 UTC (permalink / raw) To: Matthew Wilcox; +Cc: akpm, torvalds, linux-kernel On Sat, 2007-09-01 at 22:46 -0400, Matthew Wilcox wrote: > */ > if (task == current) return 0; > > - if ((task->state != TASK_STOPPED) && (task->state != > TASK_TRACED)) { > + if (!is_task_stopped_or_traced(task->state)) { > DPRINT(("cannot attach to non-stopped task [%d] state= > - if ((task->state != TASK_STOPPED) && (task->state != > TASK_TRACED)) { > + if (!is_task_stopped_or_traced(task)) { > DPRINT(("[%d] task not in stopped state\n", > task->pid)); > return -EBUSY; > } Does it take task->state or task ? Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-09-02 3:35 ` Daniel Walker @ 2007-09-02 4:05 ` Matthew Wilcox 0 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-02 4:05 UTC (permalink / raw) To: Daniel Walker; +Cc: akpm, torvalds, linux-kernel On Sat, Sep 01, 2007 at 08:35:06PM -0700, Daniel Walker wrote: > Does it take task->state or task ? task. Clearly I didn't test on ia64. (There was an iteration where it took task->state, and I guess I missed one). Thanks for pointing out this oops, I'll fix it for round three. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-09-02 2:46 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 2007-09-02 2:54 ` Matthew Wilcox 2007-09-02 3:35 ` Daniel Walker @ 2007-09-03 21:03 ` Matthew Wilcox 2 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-03 21:03 UTC (permalink / raw) To: akpm, torvalds; +Cc: linux-kernel On Sat, Sep 01, 2007 at 10:46:51PM -0400, Matthew Wilcox wrote: > Abstracting away direct uses of TASK_ flags allows us to change the > definitions of the task flags more easily. > > Also restructure do_wait() a little > > Signed-off-by: Matthew Wilcox <matthew@wil.cx> > --- > arch/ia64/kernel/perfmon.c | 4 +- > fs/proc/array.c | 9 +--- > fs/proc/base.c | 2 +- > include/linux/sched.h | 15 +++++++ > include/linux/wait.h | 11 +++-- > kernel/exit.c | 90 +++++++++++++++++++------------------------ > kernel/power/process.c | 7 +-- > kernel/ptrace.c | 8 ++-- > kernel/sched.c | 15 +++---- > kernel/signal.c | 6 +- > kernel/wait.c | 2 +- > 11 files changed, 83 insertions(+), 86 deletions(-) Here's a replacement patch 2/5, including fixes for the problems spotted by Daniel and myself. A machine running a kernel including these patches has been up for more than 24 hours. commit 10287ac5d615a2ccca6611426572259ebc69dc92 Author: Matthew Wilcox <matthew@wil.cx> Date: Sat Sep 1 09:31:22 2007 -0400 Use macros instead of TASK_ flags Abstracting away direct uses of TASK_ flags allows us to change the definitions of the task flags more easily. Also restructure do_wait() a little Signed-off-by: Matthew Wilcox <matthew@wil.cx> diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c index 14b8e5a..3690c46 100644 --- a/arch/ia64/kernel/perfmon.c +++ b/arch/ia64/kernel/perfmon.c @@ -2637,7 +2637,7 @@ pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task) */ if (task == current) return 0; - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task)) { DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task->pid, task->state)); return -EBUSY; } @@ -4797,7 +4797,7 @@ recheck: * the task must be stopped. */ if (PFM_CMD_STOPPED(cmd)) { - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task)) { DPRINT(("[%d] task not in stopped state\n", task->pid)); return -EBUSY; } diff --git a/fs/proc/array.c b/fs/proc/array.c index ee4814d..6a3c876 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -140,13 +140,8 @@ static const char *task_state_array[] = { static inline const char *get_task_state(struct task_struct *tsk) { - unsigned int state = (tsk->state & (TASK_RUNNING | - TASK_INTERRUPTIBLE | - TASK_UNINTERRUPTIBLE | - TASK_STOPPED | - TASK_TRACED)) | - (tsk->exit_state & (EXIT_ZOMBIE | - EXIT_DEAD)); + unsigned int state = (tsk->state & TASK_REPORT) | + (tsk->exit_state & (EXIT_ZOMBIE | EXIT_DEAD)); const char **p = &task_state_array[0]; while (state) { diff --git a/fs/proc/base.c b/fs/proc/base.c index 19489b0..3155ef1 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -196,7 +196,7 @@ static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vf (task == current || \ (task->parent == current && \ (task->ptrace & PT_PTRACED) && \ - (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \ + (is_task_stopped_or_traced(task)) && \ security_ptrace(current,task) == 0)) static int proc_pid_environ(struct task_struct *task, char * buffer) diff --git a/include/linux/sched.h b/include/linux/sched.h index f4e324e..ea509e9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -176,6 +176,21 @@ print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) #define TASK_NONINTERACTIVE 64 #define TASK_DEAD 128 +/* Convenience macros for the sake of wake_up */ +#define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) +#define TASK_ALL (TASK_NORMAL | TASK_STOPPED | TASK_TRACED) + +/* get_task_state() */ +#define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \ + TASK_UNINTERRUPTIBLE | TASK_STOPPED | \ + TASK_TRACED) + +#define is_task_traced(task) ((task->state & TASK_TRACED) != 0) +#define is_task_stopped(task) ((task->state & TASK_STOPPED) != 0) +#define is_task_stopped_or_traced(task) \ + ((task->state & (TASK_STOPPED | TASK_TRACED)) != 0) +#define is_task_loadavg(task) ((task->state & TASK_UNINTERRUPTIBLE) != 0) + #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) #define set_task_state(tsk, state_value) \ diff --git a/include/linux/wait.h b/include/linux/wait.h index 0e68628..0a410a4 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -152,14 +152,15 @@ int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned)); int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned)); wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int)); -#define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL) -#define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL) -#define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL) +#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) +#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) +#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL) +#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL) + #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL) #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL) #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL) -#define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE) -#define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1) +#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1) #define __wait_event(wq, condition) \ do { \ diff --git a/kernel/exit.c b/kernel/exit.c index 06b24b3..325106a 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -259,7 +259,7 @@ static int has_stopped_jobs(struct pid *pgrp) struct task_struct *p; do_each_pid_task(pgrp, PIDTYPE_PGID, p) { - if (p->state != TASK_STOPPED) + if (!is_task_stopped(p)) continue; retval = 1; break; @@ -634,7 +634,7 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) p->parent = p->real_parent; add_parent(p); - if (p->state == TASK_TRACED) { + if (is_task_traced(p)) { /* * If it was at a trace stop, turn it into * a normal stop since it's no longer being @@ -1372,7 +1372,7 @@ static int wait_task_stopped(struct task_struct *p, int delayed_group_leader, exit_code = p->exit_code; if (unlikely(!exit_code) || - unlikely(p->state & TASK_TRACED)) + unlikely(is_task_traced(p))) goto bail_ref; return wait_noreap_copyout(p, pid, uid, why, (exit_code << 8) | 0x7f, @@ -1554,60 +1554,51 @@ repeat: } allowed = 1; - switch (p->state) { - case TASK_TRACED: - /* - * When we hit the race with PTRACE_ATTACH, - * we will not report this child. But the - * race means it has not yet been moved to - * our ptrace_children list, so we need to - * set the flag here to avoid a spurious ECHILD - * when the race happens with the only child. - */ - flag = 1; - if (!my_ptrace_child(p)) - continue; - /*FALLTHROUGH*/ - case TASK_STOPPED: + if (is_task_stopped_or_traced(p)) { /* * It's stopped now, so it might later * continue, exit, or stop again. + * + * When we hit the race with PTRACE_ATTACH, we + * will not report this child. But the race + * means it has not yet been moved to our + * ptrace_children list, so we need to set the + * flag here to avoid a spurious ECHILD when + * the race happens with the only child. */ flag = 1; - if (!(options & WUNTRACED) && - !my_ptrace_child(p)) - continue; + + if (!my_ptrace_child(p)) { + if (is_task_traced(p)) + continue; + if (!(options & WUNTRACED)) + continue; + } + retval = wait_task_stopped(p, ret == 2, - (options & WNOWAIT), - infop, - stat_addr, ru); + (options & WNOWAIT), infop, + stat_addr, ru); if (retval == -EAGAIN) goto repeat; if (retval != 0) /* He released the lock. */ goto end; - break; - default: - // case EXIT_DEAD: - if (p->exit_state == EXIT_DEAD) + } else if (p->exit_state == EXIT_DEAD) { + continue; + } else if (p->exit_state == EXIT_ZOMBIE) { + /* + * Eligible but we cannot release it yet: + */ + if (ret == 2) + goto check_continued; + if (!likely(options & WEXITED)) continue; - // case EXIT_ZOMBIE: - if (p->exit_state == EXIT_ZOMBIE) { - /* - * Eligible but we cannot release - * it yet: - */ - if (ret == 2) - goto check_continued; - if (!likely(options & WEXITED)) - continue; - retval = wait_task_zombie( - p, (options & WNOWAIT), - infop, stat_addr, ru); - /* He released the lock. */ - if (retval != 0) - goto end; - break; - } + retval = wait_task_zombie(p, + (options & WNOWAIT), infop, + stat_addr, ru); + /* He released the lock. */ + if (retval != 0) + goto end; + } else { check_continued: /* * It's running now, so it might later @@ -1616,12 +1607,11 @@ check_continued: flag = 1; if (!unlikely(options & WCONTINUED)) continue; - retval = wait_task_continued( - p, (options & WNOWAIT), - infop, stat_addr, ru); + retval = wait_task_continued(p, + (options & WNOWAIT), infop, + stat_addr, ru); if (retval != 0) /* He released the lock. */ goto end; - break; } } if (!flag) { diff --git a/kernel/power/process.c b/kernel/power/process.c index 3434940..ac0c27a 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -83,10 +83,10 @@ static void freeze_task(struct task_struct *p) rmb(); if (!frozen(p)) { set_freeze_flag(p); - if (p->state == TASK_STOPPED) + if (is_task_stopped(p)) force_sig_specific(SIGSTOP, p); spin_lock_irqsave(&p->sighand->siglock, flags); - signal_wake_up(p, p->state == TASK_STOPPED); + signal_wake_up(p, is_task_stopped(p)); spin_unlock_irqrestore(&p->sighand->siglock, flags); } } @@ -120,8 +120,7 @@ static int try_to_freeze_tasks(int freeze_user_space) continue; if (freeze_user_space) { - if (p->state == TASK_TRACED && - frozen(p->parent)) { + if (is_task_traced(p) && frozen(p->parent)) { cancel_freezing(p); continue; } diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 82a558b..92a2283 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -50,7 +50,7 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) void ptrace_untrace(struct task_struct *child) { spin_lock(&child->sighand->siglock); - if (child->state == TASK_TRACED) { + if (is_task_traced(child)) { if (child->signal->flags & SIGNAL_STOP_STOPPED) { child->state = TASK_STOPPED; } else { @@ -78,7 +78,7 @@ void __ptrace_unlink(struct task_struct *child) add_parent(child); } - if (child->state == TASK_TRACED) + if (is_task_traced(child)) ptrace_untrace(child); } @@ -102,9 +102,9 @@ int ptrace_check_attach(struct task_struct *child, int kill) && child->signal != NULL) { ret = 0; spin_lock_irq(&child->sighand->siglock); - if (child->state == TASK_STOPPED) { + if (is_task_stopped(child)) { child->state = TASK_TRACED; - } else if (child->state != TASK_TRACED && !kill) { + } else if (!is_task_traced(child) && !kill) { ret = -ESRCH; } spin_unlock_irq(&child->sighand->siglock); diff --git a/kernel/sched.c b/kernel/sched.c index b533d6d..e3be352 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -944,7 +944,7 @@ static int effective_prio(struct task_struct *p) */ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, wakeup); @@ -958,7 +958,7 @@ static inline void activate_idle_task(struct task_struct *p, struct rq *rq) { update_rq_clock(rq); - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, 0); @@ -970,7 +970,7 @@ static inline void activate_idle_task(struct task_struct *p, struct rq *rq) */ static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible++; dequeue_task(rq, p, sleep); @@ -1566,8 +1566,7 @@ out: int fastcall wake_up_process(struct task_struct *p) { - return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | - TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); + return try_to_wake_up(p, TASK_ALL, 0); } EXPORT_SYMBOL(wake_up_process); @@ -3708,8 +3707,7 @@ void fastcall complete(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done++; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 1, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete); @@ -3720,8 +3718,7 @@ void fastcall complete_all(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done += UINT_MAX/2; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 0, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete_all); diff --git a/kernel/signal.c b/kernel/signal.c index 3169bed..53cbac4 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -841,7 +841,7 @@ static inline int wants_signal(int sig, struct task_struct *p) return 0; if (sig == SIGKILL) return 1; - if (p->state & (TASK_STOPPED | TASK_TRACED)) + if (is_task_stopped_or_traced(p)) return 0; return task_curr(p) || !signal_pending(p); } @@ -1445,7 +1445,7 @@ void do_notify_parent(struct task_struct *tsk, int sig) BUG_ON(sig == -1); /* do_notify_parent_cldstop should have been called instead. */ - BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); + BUG_ON(is_task_stopped_or_traced(tsk)); BUG_ON(!tsk->ptrace && (tsk->group_leader != tsk || !thread_group_empty(tsk))); @@ -1712,7 +1712,7 @@ static int do_signal_stop(int signr) * so this check has no races. */ if (!t->exit_state && - !(t->state & (TASK_STOPPED|TASK_TRACED))) { + !is_task_stopped_or_traced(t)) { stop_count++; signal_wake_up(t, 0); } diff --git a/kernel/wait.c b/kernel/wait.c index 444ddbf..f987688 100644 --- a/kernel/wait.c +++ b/kernel/wait.c @@ -215,7 +215,7 @@ void fastcall __wake_up_bit(wait_queue_head_t *wq, void *word, int bit) { struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit); if (waitqueue_active(wq)) - __wake_up(wq, TASK_INTERRUPTIBLE|TASK_UNINTERRUPTIBLE, 1, &key); + __wake_up(wq, TASK_NORMAL, 1, &key); } EXPORT_SYMBOL(__wake_up_bit); -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 3/5] Add TASK_WAKEKILL 2007-09-02 2:43 [PATCH] TASK_KILLABLE version 2 Matthew Wilcox 2007-09-02 2:46 ` [PATCH 1/5] Use wake_up_locked() in eventpoll Matthew Wilcox 2007-09-02 2:46 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox @ 2007-09-02 2:46 ` Matthew Wilcox 2007-09-02 2:46 ` [PATCH 4/5] Add lock_page_killable Matthew Wilcox ` (2 subsequent siblings) 5 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-02 2:46 UTC (permalink / raw) To: akpm, torvalds; +Cc: linux-kernel, Matthew Wilcox Set TASK_WAKEKILL for TASK_STOPPED and TASK_TRACED, add TASK_KILLABLE and use TASK_WAKEKILL in signal_wake_up() Signed-off-by: Matthew Wilcox <matthew@wil.cx> --- include/linux/sched.h | 22 ++++++++++++++-------- kernel/signal.c | 8 ++++---- 2 files changed, 18 insertions(+), 12 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index ea509e9..6769179 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -167,28 +167,34 @@ print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) #define TASK_RUNNING 0 #define TASK_INTERRUPTIBLE 1 #define TASK_UNINTERRUPTIBLE 2 -#define TASK_STOPPED 4 -#define TASK_TRACED 8 +#define __TASK_STOPPED 4 +#define __TASK_TRACED 8 /* in tsk->exit_state */ #define EXIT_ZOMBIE 16 #define EXIT_DEAD 32 /* in tsk->state again */ #define TASK_NONINTERACTIVE 64 #define TASK_DEAD 128 +#define TASK_WAKEKILL 256 + +/* Convenience macros for the sake of set_task_state */ +#define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE) +#define TASK_STOPPED (TASK_WAKEKILL | __TASK_STOPPED) +#define TASK_TRACED (TASK_WAKEKILL | __TASK_TRACED) /* Convenience macros for the sake of wake_up */ #define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) -#define TASK_ALL (TASK_NORMAL | TASK_STOPPED | TASK_TRACED) +#define TASK_ALL (TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED) /* get_task_state() */ #define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \ - TASK_UNINTERRUPTIBLE | TASK_STOPPED | \ - TASK_TRACED) + TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \ + __TASK_TRACED) -#define is_task_traced(task) ((task->state & TASK_TRACED) != 0) -#define is_task_stopped(task) ((task->state & TASK_STOPPED) != 0) +#define is_task_traced(task) ((task->state & __TASK_TRACED) != 0) +#define is_task_stopped(task) ((task->state & __TASK_STOPPED) != 0) #define is_task_stopped_or_traced(task) \ - ((task->state & (TASK_STOPPED | TASK_TRACED)) != 0) + ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0) #define is_task_loadavg(task) ((task->state & TASK_UNINTERRUPTIBLE) != 0) #define __set_task_state(tsk, state_value) \ diff --git a/kernel/signal.c b/kernel/signal.c index 53cbac4..986ba10 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -459,15 +459,15 @@ void signal_wake_up(struct task_struct *t, int resume) set_tsk_thread_flag(t, TIF_SIGPENDING); /* - * For SIGKILL, we want to wake it up in the stopped/traced case. - * We don't check t->state here because there is a race with it + * For SIGKILL, we want to wake it up in the stopped/traced/killable + * case. We don't check t->state here because there is a race with it * executing another processor and just now entering stopped state. * By using wake_up_state, we ensure the process will wake up and * handle its death signal. */ mask = TASK_INTERRUPTIBLE; if (resume) - mask |= TASK_STOPPED | TASK_TRACED; + mask |= TASK_WAKEKILL; if (!wake_up_state(t, mask)) kick_process(t); } @@ -623,7 +623,7 @@ static void handle_stop_signal(int sig, struct task_struct *p) * Wake up the stopped thread _after_ setting * TIF_SIGPENDING */ - state = TASK_STOPPED; + state = __TASK_STOPPED; if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { set_tsk_thread_flag(t, TIF_SIGPENDING); state |= TASK_INTERRUPTIBLE; -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 4/5] Add lock_page_killable 2007-09-02 2:43 [PATCH] TASK_KILLABLE version 2 Matthew Wilcox ` (2 preceding siblings ...) 2007-09-02 2:46 ` [PATCH 3/5] Add TASK_WAKEKILL Matthew Wilcox @ 2007-09-02 2:46 ` Matthew Wilcox 2007-09-02 2:46 ` [PATCH 5/5] Make wait_on_retry_sync_kiocb killable Matthew Wilcox 2007-09-24 20:16 ` [PATCH] TASK_KILLABLE version 2 Bob Bell 5 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-02 2:46 UTC (permalink / raw) To: akpm, torvalds; +Cc: linux-kernel, Matthew Wilcox and associated infrastructure such as sync_page_killable and fatal_signal_pending. Use lock_page_killable in do_generic_mapping_read() to allow us to kill `cat' of a file on an NFS-mounted filesystem. Signed-off-by: Matthew Wilcox <matthew@wil.cx> --- include/linux/pagemap.h | 14 ++++++++++++++ include/linux/sched.h | 9 ++++++++- kernel/signal.c | 5 +++++ mm/filemap.c | 25 +++++++++++++++++++++---- 4 files changed, 48 insertions(+), 5 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 8a83537..8b4f533 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -154,6 +154,7 @@ static inline pgoff_t linear_page_index(struct vm_area_struct *vma, } extern void FASTCALL(__lock_page(struct page *page)); +extern int FASTCALL(__lock_page_killable(struct page *page)); extern void FASTCALL(__lock_page_nosync(struct page *page)); extern void FASTCALL(unlock_page(struct page *page)); @@ -168,6 +169,19 @@ static inline void lock_page(struct page *page) } /* + * lock_page_killable is like lock_page but can be interrupted by fatal + * signals. It returns 0 if it locked the page and -EINTR if it was + * killed while waiting. + */ +static inline int lock_page_killable(struct page *page) +{ + might_sleep(); + if (TestSetPageLocked(page)) + return __lock_page_killable(page); + return 0; +} + +/* * lock_page_nosync should only be used if we can't pin the page's inode. * Doesn't play quite so well with block device plugging. */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 6769179..e6f20da 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1769,7 +1769,14 @@ static inline int signal_pending(struct task_struct *p) { return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING)); } - + +extern int FASTCALL(__fatal_signal_pending(struct task_struct *p)); + +static inline int fatal_signal_pending(struct task_struct *p) +{ + return signal_pending(p) && __fatal_signal_pending(p); +} + static inline int need_resched(void) { return unlikely(test_thread_flag(TIF_NEED_RESCHED)); diff --git a/kernel/signal.c b/kernel/signal.c index 986ba10..2b4fe29 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1003,6 +1003,11 @@ void zap_other_threads(struct task_struct *p) } } +int fastcall __fatal_signal_pending(struct task_struct *tsk) +{ + return sigismember(&tsk->pending.signal, SIGKILL); +} + /* * Must be called under rcu_read_lock() or with tasklist_lock read-held. */ diff --git a/mm/filemap.c b/mm/filemap.c index 90b657b..235f092 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -170,6 +170,12 @@ static int sync_page(void *word) return 0; } +static int sync_page_killable(void *word) +{ + sync_page(word); + return fatal_signal_pending(current) ? -EINTR : 0; +} + /** * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range * @mapping: address space structure to write @@ -574,6 +580,14 @@ void fastcall __lock_page(struct page *page) } EXPORT_SYMBOL(__lock_page); +int fastcall __lock_page_killable(struct page *page) +{ + DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); + + return __wait_on_bit_lock(page_waitqueue(page), &wait, + sync_page_killable, TASK_KILLABLE); +} + /* * Variant of lock_page that does not require the caller to hold a reference * on the page's mapping. @@ -975,7 +989,8 @@ page_ok: page_not_up_to_date: /* Get exclusive access to the page ... */ - lock_page(page); + if (lock_page_killable(page)) + goto readpage_eio; /* Did it get truncated before we got the lock? */ if (!page->mapping) { @@ -1003,7 +1018,8 @@ readpage: } if (!PageUptodate(page)) { - lock_page(page); + if (lock_page_killable(page)) + goto readpage_eio; if (!PageUptodate(page)) { if (page->mapping == NULL) { /* @@ -1014,15 +1030,16 @@ readpage: goto find_page; } unlock_page(page); - error = -EIO; shrink_readahead_size_eio(filp, &ra); - goto readpage_error; + goto readpage_eio; } unlock_page(page); } goto page_ok; +readpage_eio: + error = -EIO; readpage_error: /* UHHUH! A synchronous read error occurred. Report it */ desc->error = error; -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 5/5] Make wait_on_retry_sync_kiocb killable 2007-09-02 2:43 [PATCH] TASK_KILLABLE version 2 Matthew Wilcox ` (3 preceding siblings ...) 2007-09-02 2:46 ` [PATCH 4/5] Add lock_page_killable Matthew Wilcox @ 2007-09-02 2:46 ` Matthew Wilcox 2007-09-24 20:16 ` [PATCH] TASK_KILLABLE version 2 Bob Bell 5 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-09-02 2:46 UTC (permalink / raw) To: akpm, torvalds; +Cc: linux-kernel, Matthew Wilcox Use TASK_KILLABLE to allow wait_on_retry_sync_kiocb to return -EINTR. All callers then check the return value and break out of their loops. Signed-off-by: Matthew Wilcox <matthew@wil.cx> --- fs/read_write.c | 17 ++++++++++++----- 1 files changed, 12 insertions(+), 5 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 507ddff..b1a52d5 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -218,14 +218,15 @@ Einval: return -EINVAL; } -static void wait_on_retry_sync_kiocb(struct kiocb *iocb) +static int wait_on_retry_sync_kiocb(struct kiocb *iocb) { - set_current_state(TASK_UNINTERRUPTIBLE); + set_current_state(TASK_KILLABLE); if (!kiocbIsKicked(iocb)) schedule(); else kiocbClearKicked(iocb); __set_current_state(TASK_RUNNING); + return fatal_signal_pending(current) ? -EINTR : 0; } ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) @@ -242,7 +243,9 @@ ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *pp ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); if (ret != -EIOCBRETRY) break; - wait_on_retry_sync_kiocb(&kiocb); + ret = wait_on_retry_sync_kiocb(&kiocb); + if (ret) + break; } if (-EIOCBQUEUED == ret) @@ -300,7 +303,9 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); if (ret != -EIOCBRETRY) break; - wait_on_retry_sync_kiocb(&kiocb); + ret = wait_on_retry_sync_kiocb(&kiocb); + if (ret) + break; } if (-EIOCBQUEUED == ret) @@ -466,7 +471,9 @@ ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); if (ret != -EIOCBRETRY) break; - wait_on_retry_sync_kiocb(&kiocb); + ret = wait_on_retry_sync_kiocb(&kiocb); + if (ret) + break; } if (ret == -EIOCBQUEUED) -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH] TASK_KILLABLE version 2 2007-09-02 2:43 [PATCH] TASK_KILLABLE version 2 Matthew Wilcox ` (4 preceding siblings ...) 2007-09-02 2:46 ` [PATCH 5/5] Make wait_on_retry_sync_kiocb killable Matthew Wilcox @ 2007-09-24 20:16 ` Bob Bell 2007-09-26 11:57 ` Ric Wheeler 2007-12-07 1:49 ` Matthew Wilcox 5 siblings, 2 replies; 23+ messages in thread From: Bob Bell @ 2007-09-24 20:16 UTC (permalink / raw) To: Matthew Wilcox; +Cc: Andrew Morton, Linus Torvalds, trond, linux-kernel On Sat, Sep 01, 2007 at 08:43:49PM -0600, Matthew Wilcox wrote: > Here's the second version of TASK_KILLABLE. A few changes since version 1: <snip> > I obviously haven't covered every place that can result in a process > sleeping uninterruptibly while attempting an operation. But sync_page > (patch 4/5) covers about 90% of the times I've attempted to kill cat, > and I hope that by providing the two examples, I can help other people > to fix the cases that they find interesting. I've been testing this patch on my systems. It's working for me when I read() a file. Asynchronous write()s seem okay, too. However, synchronous writes (caused by either calling fsync() or fcntl() to release a lock) prevent the process from being killed when the NFS server goes down. When the process is sent SIGKILL, it's waiting with the following call tree: do_fsync nfs_fsync nfs_wb_all nfs_sync_mapping_wait nfs_wait_on_requests_locks (I believe) nfs_wait_on_request out_of_line_wait_on_bit __wait_on_bit nfs_wait_bit_interruptible schedule When the process is later viewed after being deemed "stuck", it's waiting with the following call tree: do_fsync filemap_fdatawait wait_on_page_writeback_range wait_on_page_writeback wait_on_page_bit __wait_on_bit sync_page io_schedule schedule If I hazard a guess as to what might be wrong here, I believe that when the processes catches SIGKILL, nfs_wait_bit_interruptible is returning -ERESTARTSYS. That error bubbles back up to nfs_fsync. However, nfs_fsync returns ctx->error, not -ERESTARTSYS, and ctx->error is 0. do_fsync proceeds to call filemap_fdatawait. I question whether nfs_sync should return an error, and if do_fsync should skip filemap_fdatawait if the fsync op returned an error. I did try replacing the call to sync_page in __wait_on_bit with sync_page_killable and replacing TASK_UNINTERRUPTIBLE with TASK_KILLABLE. That seemed to work once, but then really screwed things up on subsequent attempts. -- Bob Bell ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH] TASK_KILLABLE version 2 2007-09-24 20:16 ` [PATCH] TASK_KILLABLE version 2 Bob Bell @ 2007-09-26 11:57 ` Ric Wheeler 2007-09-27 21:47 ` Nick Piggin 2007-12-07 1:49 ` Matthew Wilcox 1 sibling, 1 reply; 23+ messages in thread From: Ric Wheeler @ 2007-09-26 11:57 UTC (permalink / raw) To: Nick Piggin, Chris Mason, Mark Lord, Valerie Henson, Christoph Hellwig, Suparna Bhattacharya, Andreas Dilger Cc: Bob Bell, Matthew Wilcox, trond, linux-kernel Bob Bell wrote: > On Sat, Sep 01, 2007 at 08:43:49PM -0600, Matthew Wilcox wrote: >> Here's the second version of TASK_KILLABLE. A few changes since >> version 1: > <snip> >> I obviously haven't covered every place that can result in a process >> sleeping uninterruptibly while attempting an operation. But sync_page >> (patch 4/5) covers about 90% of the times I've attempted to kill cat, >> and I hope that by providing the two examples, I can help other people >> to fix the cases that they find interesting. > > I've been testing this patch on my systems. It's working for me when > I read() a file. Asynchronous write()s seem okay, too. However, > synchronous writes (caused by either calling fsync() or fcntl() to > release a lock) prevent the process from being killed when the NFS > server goes down. After hearing again last month about how few people actually read every lkml thread, I wanted to point you all at this thread explicitly since it seems that we are getting somewhat close to having a forced unmount that actually is usable by real applications, something that we seem to have been talking about for many years ;-) With Matthew's original TASK_KILLABLE patch, we have a solution for a task read, but still have some holes (fsync & fcntl, others?) that need fixed as well for NFS clients. Is this patch going in the right direction? ric ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH] TASK_KILLABLE version 2 2007-09-26 11:57 ` Ric Wheeler @ 2007-09-27 21:47 ` Nick Piggin 0 siblings, 0 replies; 23+ messages in thread From: Nick Piggin @ 2007-09-27 21:47 UTC (permalink / raw) To: ric, Andrea Arcangeli Cc: Chris Mason, Mark Lord, Valerie Henson, Christoph Hellwig, Suparna Bhattacharya, Andreas Dilger, Bob Bell, Matthew Wilcox, trond, linux-kernel On Wednesday 26 September 2007 21:57, Ric Wheeler wrote: > Bob Bell wrote: > > On Sat, Sep 01, 2007 at 08:43:49PM -0600, Matthew Wilcox wrote: > >> Here's the second version of TASK_KILLABLE. A few changes since > >> version 1: > > > > <snip> > > > >> I obviously haven't covered every place that can result in a process > >> sleeping uninterruptibly while attempting an operation. But sync_page > >> (patch 4/5) covers about 90% of the times I've attempted to kill cat, > >> and I hope that by providing the two examples, I can help other people > >> to fix the cases that they find interesting. > > > > I've been testing this patch on my systems. It's working for me when > > I read() a file. Asynchronous write()s seem okay, too. However, > > synchronous writes (caused by either calling fsync() or fcntl() to > > release a lock) prevent the process from being killed when the NFS > > server goes down. > > After hearing again last month about how few people actually read every > lkml thread, I wanted to point you all at this thread explicitly since > it seems that we are getting somewhat close to having a forced unmount > that actually is usable by real applications, something that we seem to > have been talking about for many years ;-) > > With Matthew's original TASK_KILLABLE patch, we have a solution for a > task read, but still have some holes (fsync & fcntl, others?) that need > fixed as well for NFS clients. > > Is this patch going in the right direction? FWIW, I do think it seems like a good idea to work towards better interruptibility in various potentially long-blocking paths like these. I think Andrea's recent work to solve some oom killer deadlocks probably has some requirements in common with this patch. ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH] TASK_KILLABLE version 2 2007-09-24 20:16 ` [PATCH] TASK_KILLABLE version 2 Bob Bell 2007-09-26 11:57 ` Ric Wheeler @ 2007-12-07 1:49 ` Matthew Wilcox 1 sibling, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-12-07 1:49 UTC (permalink / raw) To: Bob Bell; +Cc: Andrew Morton, Linus Torvalds, trond, linux-kernel On Mon, Sep 24, 2007 at 04:16:48PM -0400, Bob Bell wrote: > I've been testing this patch on my systems. It's working for me when > I read() a file. Asynchronous write()s seem okay, too. However, > synchronous writes (caused by either calling fsync() or fcntl() to > release a lock) prevent the process from being killed when the NFS > server goes down. > > When the process is sent SIGKILL, it's waiting with the following call > tree: > do_fsync > nfs_fsync > nfs_wb_all > nfs_sync_mapping_wait > nfs_wait_on_requests_locks (I believe) > nfs_wait_on_request > out_of_line_wait_on_bit > __wait_on_bit > nfs_wait_bit_interruptible > schedule > > When the process is later viewed after being deemed "stuck", it's > waiting with the following call tree: > do_fsync > filemap_fdatawait > wait_on_page_writeback_range > wait_on_page_writeback > wait_on_page_bit > __wait_on_bit > sync_page > io_schedule > schedule > > If I hazard a guess as to what might be wrong here, I believe that when > the processes catches SIGKILL, nfs_wait_bit_interruptible is returning > -ERESTARTSYS. That error bubbles back up to nfs_fsync. However, > nfs_fsync returns ctx->error, not -ERESTARTSYS, and ctx->error is 0. > do_fsync proceeds to call filemap_fdatawait. I question whether > nfs_sync should return an error, and if do_fsync should skip > filemap_fdatawait if the fsync op returned an error. > > I did try replacing the call to sync_page in __wait_on_bit with > sync_page_killable and replacing TASK_UNINTERRUPTIBLE with > TASK_KILLABLE. That seemed to work once, but then really screwed things > up on subsequent attempts. Hi Bob, The patch I posted earlier today (a somewhat cleaned-up version of a patch originally from Liam Howlett) converts NFS to use TASK_KILLABLE. Could you have another shot at breaking it? You can find it here: http://marc.info/?l=linux-fsdevel&m=119698206729969&w=2 (It has some prerequisites that are in the git tree, so probably the easiest thing is just to pull that git tree). Liam notes that there's still problems with programs that call *stat*(), but I haven't looked into that issue yet. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 0/5] TASK_KILLABLE @ 2007-10-18 22:25 Matthew Wilcox 2007-10-18 22:25 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 0 siblings, 1 reply; 23+ messages in thread From: Matthew Wilcox @ 2007-10-18 22:25 UTC (permalink / raw) To: linux-kernel; +Cc: Matthew Wilcox This series of patches introduces the facility to deliver only fatal signals to tasks which are otherwise waiting uninterruptibly. ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-18 22:25 [PATCH 0/5] TASK_KILLABLE Matthew Wilcox @ 2007-10-18 22:25 ` Matthew Wilcox 2007-10-25 3:50 ` Nick Piggin 0 siblings, 1 reply; 23+ messages in thread From: Matthew Wilcox @ 2007-10-18 22:25 UTC (permalink / raw) To: linux-kernel; +Cc: Matthew Wilcox, Matthew Wilcox Abstracting away direct uses of TASK_ flags allows us to change the definitions of the task flags more easily. Also restructure do_wait() a little Signed-off-by: Matthew Wilcox <willy@linux.intel.com> --- arch/ia64/kernel/perfmon.c | 4 +- fs/proc/array.c | 9 +--- fs/proc/base.c | 2 +- include/linux/sched.h | 15 +++++++ include/linux/wait.h | 11 +++-- kernel/exit.c | 90 +++++++++++++++++++------------------------ kernel/power/process.c | 7 +-- kernel/ptrace.c | 8 ++-- kernel/sched.c | 15 +++---- kernel/signal.c | 6 +- kernel/wait.c | 2 +- 11 files changed, 83 insertions(+), 86 deletions(-) diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c index f55fa07..6b0a6cf 100644 --- a/arch/ia64/kernel/perfmon.c +++ b/arch/ia64/kernel/perfmon.c @@ -2630,7 +2630,7 @@ pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task) */ if (task == current) return 0; - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task)) { DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task->pid, task->state)); return -EBUSY; } @@ -4790,7 +4790,7 @@ recheck: * the task must be stopped. */ if (PFM_CMD_STOPPED(cmd)) { - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task)) { DPRINT(("[%d] task not in stopped state\n", task->pid)); return -EBUSY; } diff --git a/fs/proc/array.c b/fs/proc/array.c index 27b59f5..8939bf0 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -140,13 +140,8 @@ static const char *task_state_array[] = { static inline const char *get_task_state(struct task_struct *tsk) { - unsigned int state = (tsk->state & (TASK_RUNNING | - TASK_INTERRUPTIBLE | - TASK_UNINTERRUPTIBLE | - TASK_STOPPED | - TASK_TRACED)) | - (tsk->exit_state & (EXIT_ZOMBIE | - EXIT_DEAD)); + unsigned int state = (tsk->state & TASK_REPORT) | + (tsk->exit_state & (EXIT_ZOMBIE | EXIT_DEAD)); const char **p = &task_state_array[0]; while (state) { diff --git a/fs/proc/base.c b/fs/proc/base.c index 4fe74d1..e7e1815 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -196,7 +196,7 @@ static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vf (task == current || \ (task->parent == current && \ (task->ptrace & PT_PTRACED) && \ - (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \ + (is_task_stopped_or_traced(task)) && \ security_ptrace(current,task) == 0)) static int proc_pid_cmdline(struct task_struct *task, char * buffer) diff --git a/include/linux/sched.h b/include/linux/sched.h index c204ab0..5ef5253 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -177,6 +177,21 @@ print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) /* in tsk->state again */ #define TASK_DEAD 64 +/* Convenience macros for the sake of wake_up */ +#define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) +#define TASK_ALL (TASK_NORMAL | TASK_STOPPED | TASK_TRACED) + +/* get_task_state() */ +#define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \ + TASK_UNINTERRUPTIBLE | TASK_STOPPED | \ + TASK_TRACED) + +#define is_task_traced(task) ((task->state & TASK_TRACED) != 0) +#define is_task_stopped(task) ((task->state & TASK_STOPPED) != 0) +#define is_task_stopped_or_traced(task) \ + ((task->state & (TASK_STOPPED | TASK_TRACED)) != 0) +#define is_task_loadavg(task) ((task->state & TASK_UNINTERRUPTIBLE) != 0) + #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) #define set_task_state(tsk, state_value) \ diff --git a/include/linux/wait.h b/include/linux/wait.h index 0e68628..0a410a4 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -152,14 +152,15 @@ int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned)); int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned)); wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int)); -#define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL) -#define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL) -#define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL) +#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) +#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) +#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL) +#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL) + #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL) #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL) #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL) -#define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE) -#define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1) +#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1) #define __wait_event(wq, condition) \ do { \ diff --git a/kernel/exit.c b/kernel/exit.c index 2c704c8..f3c6e8c 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -249,7 +249,7 @@ static int has_stopped_jobs(struct pid *pgrp) struct task_struct *p; do_each_pid_task(pgrp, PIDTYPE_PGID, p) { - if (p->state != TASK_STOPPED) + if (!is_task_stopped(p)) continue; retval = 1; break; @@ -613,7 +613,7 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) p->parent = p->real_parent; add_parent(p); - if (p->state == TASK_TRACED) { + if (is_task_traced(p)) { /* * If it was at a trace stop, turn it into * a normal stop since it's no longer being @@ -1354,7 +1354,7 @@ static int wait_task_stopped(struct task_struct *p, int delayed_group_leader, exit_code = p->exit_code; if (unlikely(!exit_code) || - unlikely(p->state & TASK_TRACED)) + unlikely(is_task_traced(p))) goto bail_ref; return wait_noreap_copyout(p, pid, uid, why, (exit_code << 8) | 0x7f, @@ -1533,60 +1533,51 @@ repeat: } allowed = 1; - switch (p->state) { - case TASK_TRACED: - /* - * When we hit the race with PTRACE_ATTACH, - * we will not report this child. But the - * race means it has not yet been moved to - * our ptrace_children list, so we need to - * set the flag here to avoid a spurious ECHILD - * when the race happens with the only child. - */ - flag = 1; - if (!my_ptrace_child(p)) - continue; - /*FALLTHROUGH*/ - case TASK_STOPPED: + if (is_task_stopped_or_traced(p)) { /* * It's stopped now, so it might later * continue, exit, or stop again. + * + * When we hit the race with PTRACE_ATTACH, we + * will not report this child. But the race + * means it has not yet been moved to our + * ptrace_children list, so we need to set the + * flag here to avoid a spurious ECHILD when + * the race happens with the only child. */ flag = 1; - if (!(options & WUNTRACED) && - !my_ptrace_child(p)) - continue; + + if (!my_ptrace_child(p)) { + if (is_task_traced(p)) + continue; + if (!(options & WUNTRACED)) + continue; + } + retval = wait_task_stopped(p, ret == 2, - (options & WNOWAIT), - infop, - stat_addr, ru); + (options & WNOWAIT), infop, + stat_addr, ru); if (retval == -EAGAIN) goto repeat; if (retval != 0) /* He released the lock. */ goto end; - break; - default: - // case EXIT_DEAD: - if (p->exit_state == EXIT_DEAD) + } else if (p->exit_state == EXIT_DEAD) { + continue; + } else if (p->exit_state == EXIT_ZOMBIE) { + /* + * Eligible but we cannot release it yet: + */ + if (ret == 2) + goto check_continued; + if (!likely(options & WEXITED)) continue; - // case EXIT_ZOMBIE: - if (p->exit_state == EXIT_ZOMBIE) { - /* - * Eligible but we cannot release - * it yet: - */ - if (ret == 2) - goto check_continued; - if (!likely(options & WEXITED)) - continue; - retval = wait_task_zombie( - p, (options & WNOWAIT), - infop, stat_addr, ru); - /* He released the lock. */ - if (retval != 0) - goto end; - break; - } + retval = wait_task_zombie(p, + (options & WNOWAIT), infop, + stat_addr, ru); + /* He released the lock. */ + if (retval != 0) + goto end; + } else { check_continued: /* * It's running now, so it might later @@ -1595,12 +1586,11 @@ check_continued: flag = 1; if (!unlikely(options & WCONTINUED)) continue; - retval = wait_task_continued( - p, (options & WNOWAIT), - infop, stat_addr, ru); + retval = wait_task_continued(p, + (options & WNOWAIT), infop, + stat_addr, ru); if (retval != 0) /* He released the lock. */ goto end; - break; } } if (!flag) { diff --git a/kernel/power/process.c b/kernel/power/process.c index 3434940..ac0c27a 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -83,10 +83,10 @@ static void freeze_task(struct task_struct *p) rmb(); if (!frozen(p)) { set_freeze_flag(p); - if (p->state == TASK_STOPPED) + if (is_task_stopped(p)) force_sig_specific(SIGSTOP, p); spin_lock_irqsave(&p->sighand->siglock, flags); - signal_wake_up(p, p->state == TASK_STOPPED); + signal_wake_up(p, is_task_stopped(p)); spin_unlock_irqrestore(&p->sighand->siglock, flags); } } @@ -120,8 +120,7 @@ static int try_to_freeze_tasks(int freeze_user_space) continue; if (freeze_user_space) { - if (p->state == TASK_TRACED && - frozen(p->parent)) { + if (is_task_traced(p) && frozen(p->parent)) { cancel_freezing(p); continue; } diff --git a/kernel/ptrace.c b/kernel/ptrace.c index a73ebd3..7d1ef3b 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -50,7 +50,7 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) void ptrace_untrace(struct task_struct *child) { spin_lock(&child->sighand->siglock); - if (child->state == TASK_TRACED) { + if (is_task_traced(child)) { if (child->signal->flags & SIGNAL_STOP_STOPPED) { child->state = TASK_STOPPED; } else { @@ -78,7 +78,7 @@ void __ptrace_unlink(struct task_struct *child) add_parent(child); } - if (child->state == TASK_TRACED) + if (is_task_traced(child)) ptrace_untrace(child); } @@ -102,9 +102,9 @@ int ptrace_check_attach(struct task_struct *child, int kill) && child->signal != NULL) { ret = 0; spin_lock_irq(&child->sighand->siglock); - if (child->state == TASK_STOPPED) { + if (is_task_stopped(child)) { child->state = TASK_TRACED; - } else if (child->state != TASK_TRACED && !kill) { + } else if (!is_task_traced(child) && !kill) { ret = -ESRCH; } spin_unlock_irq(&child->sighand->siglock); diff --git a/kernel/sched.c b/kernel/sched.c index 92721d1..04f6141 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -961,7 +961,7 @@ static int effective_prio(struct task_struct *p) */ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, wakeup); @@ -973,7 +973,7 @@ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) */ static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible++; dequeue_task(rq, p, sleep); @@ -1609,8 +1609,7 @@ out: int fastcall wake_up_process(struct task_struct *p) { - return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | - TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); + return try_to_wake_up(p, TASK_ALL, 0); } EXPORT_SYMBOL(wake_up_process); @@ -3786,8 +3785,7 @@ void fastcall complete(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done++; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 1, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete); @@ -3798,8 +3796,7 @@ void fastcall complete_all(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done += UINT_MAX/2; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 0, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete_all); @@ -5172,7 +5169,7 @@ static void activate_idle_task(struct task_struct *p, struct rq *rq) { update_rq_clock(rq); - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, 0); diff --git a/kernel/signal.c b/kernel/signal.c index 2124ffa..16c16a3 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -839,7 +839,7 @@ static inline int wants_signal(int sig, struct task_struct *p) return 0; if (sig == SIGKILL) return 1; - if (p->state & (TASK_STOPPED | TASK_TRACED)) + if (is_task_stopped_or_traced(p)) return 0; return task_curr(p) || !signal_pending(p); } @@ -1437,7 +1437,7 @@ void do_notify_parent(struct task_struct *tsk, int sig) BUG_ON(sig == -1); /* do_notify_parent_cldstop should have been called instead. */ - BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); + BUG_ON(is_task_stopped_or_traced(tsk)); BUG_ON(!tsk->ptrace && (tsk->group_leader != tsk || !thread_group_empty(tsk))); @@ -1704,7 +1704,7 @@ static int do_signal_stop(int signr) * so this check has no races. */ if (!t->exit_state && - !(t->state & (TASK_STOPPED|TASK_TRACED))) { + !is_task_stopped_or_traced(t)) { stop_count++; signal_wake_up(t, 0); } diff --git a/kernel/wait.c b/kernel/wait.c index 444ddbf..f987688 100644 --- a/kernel/wait.c +++ b/kernel/wait.c @@ -215,7 +215,7 @@ void fastcall __wake_up_bit(wait_queue_head_t *wq, void *word, int bit) { struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit); if (waitqueue_active(wq)) - __wake_up(wq, TASK_INTERRUPTIBLE|TASK_UNINTERRUPTIBLE, 1, &key); + __wake_up(wq, TASK_NORMAL, 1, &key); } EXPORT_SYMBOL(__wake_up_bit); -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-18 22:25 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox @ 2007-10-25 3:50 ` Nick Piggin 0 siblings, 0 replies; 23+ messages in thread From: Nick Piggin @ 2007-10-25 3:50 UTC (permalink / raw) To: Matthew Wilcox; +Cc: linux-kernel, Matthew Wilcox On Friday 19 October 2007 08:25, Matthew Wilcox wrote: > Abstracting away direct uses of TASK_ flags allows us to change the > definitions of the task flags more easily. > > Also restructure do_wait() a little > > Signed-off-by: Matthew Wilcox <willy@linux.intel.com> > --- > arch/ia64/kernel/perfmon.c | 4 +- > fs/proc/array.c | 9 +--- > fs/proc/base.c | 2 +- > include/linux/sched.h | 15 +++++++ > include/linux/wait.h | 11 +++-- > kernel/exit.c | 90 > +++++++++++++++++++------------------------ kernel/power/process.c | > 7 +-- > kernel/ptrace.c | 8 ++-- > kernel/sched.c | 15 +++---- > kernel/signal.c | 6 +- > kernel/wait.c | 2 +- > 11 files changed, 83 insertions(+), 86 deletions(-) > > diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c > index f55fa07..6b0a6cf 100644 > --- a/arch/ia64/kernel/perfmon.c > +++ b/arch/ia64/kernel/perfmon.c > @@ -2630,7 +2630,7 @@ pfm_task_incompatible(pfm_context_t *ctx, struct > task_struct *task) */ > if (task == current) return 0; > > - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { > + if (!is_task_stopped_or_traced(task)) { > DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task->pid, > task->state)); return -EBUSY; > } > @@ -4790,7 +4790,7 @@ recheck: > * the task must be stopped. > */ > if (PFM_CMD_STOPPED(cmd)) { > - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { > + if (!is_task_stopped_or_traced(task)) { > DPRINT(("[%d] task not in stopped state\n", task->pid)); > return -EBUSY; > } > diff --git a/fs/proc/array.c b/fs/proc/array.c > index 27b59f5..8939bf0 100644 > --- a/fs/proc/array.c > +++ b/fs/proc/array.c > @@ -140,13 +140,8 @@ static const char *task_state_array[] = { > > static inline const char *get_task_state(struct task_struct *tsk) > { > - unsigned int state = (tsk->state & (TASK_RUNNING | > - TASK_INTERRUPTIBLE | > - TASK_UNINTERRUPTIBLE | > - TASK_STOPPED | > - TASK_TRACED)) | > - (tsk->exit_state & (EXIT_ZOMBIE | > - EXIT_DEAD)); > + unsigned int state = (tsk->state & TASK_REPORT) | > + (tsk->exit_state & (EXIT_ZOMBIE | EXIT_DEAD)); > const char **p = &task_state_array[0]; > > while (state) { > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 4fe74d1..e7e1815 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -196,7 +196,7 @@ static int proc_root_link(struct inode *inode, struct > dentry **dentry, struct vf (task == current || \ > (task->parent == current && \ > (task->ptrace & PT_PTRACED) && \ > - (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \ > + (is_task_stopped_or_traced(task)) && \ > security_ptrace(current,task) == 0)) > > static int proc_pid_cmdline(struct task_struct *task, char * buffer) > diff --git a/include/linux/sched.h b/include/linux/sched.h > index c204ab0..5ef5253 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -177,6 +177,21 @@ print_cfs_rq(struct seq_file *m, int cpu, struct > cfs_rq *cfs_rq) /* in tsk->state again */ > #define TASK_DEAD 64 > > +/* Convenience macros for the sake of wake_up */ > +#define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) > +#define TASK_ALL (TASK_NORMAL | TASK_STOPPED | TASK_TRACED) > + > +/* get_task_state() */ > +#define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \ > + TASK_UNINTERRUPTIBLE | TASK_STOPPED | \ > + TASK_TRACED) I think it would be nicer if you made it explicit in the name that these are not individual flags. Maybe it doesn't matter though... Also, TASK_NORMAL / TASK_ALL aren't very good names. TASK_SLEEP_NORMAL TASK_SLEEP_ALL might be a bit more helpful? ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 1/5] Use wake_up_locked() in eventpoll @ 2007-10-24 12:24 Matthew Wilcox 2007-10-24 12:24 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 0 siblings, 1 reply; 23+ messages in thread From: Matthew Wilcox @ 2007-10-24 12:24 UTC (permalink / raw) To: torvalds, akpm, linux-kernel; +Cc: Matthew Wilcox, Matthew Wilcox Replace the uses of __wake_up_locked with wake_up_locked Signed-off-by: Matthew Wilcox <willy@linux.intel.com> --- fs/eventpoll.c | 11 ++++------- 1 files changed, 4 insertions(+), 7 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 34f68f3..81c04ab 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -656,8 +656,7 @@ is_linked: * wait list. */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | - TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; @@ -780,7 +779,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, /* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } @@ -854,8 +853,7 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even /* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | - TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } @@ -978,8 +976,7 @@ errxit: * wait list (delayed after we release the lock). */ if (waitqueue_active(&ep->wq)) - __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | - TASK_INTERRUPTIBLE); + wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-24 12:24 [PATCH 1/5] Use wake_up_locked() in eventpoll Matthew Wilcox @ 2007-10-24 12:24 ` Matthew Wilcox 2007-10-25 3:31 ` Andrew Morton ` (2 more replies) 0 siblings, 3 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-10-24 12:24 UTC (permalink / raw) To: torvalds, akpm, linux-kernel; +Cc: Matthew Wilcox, Matthew Wilcox Abstracting away direct uses of TASK_ flags allows us to change the definitions of the task flags more easily. Also restructure do_wait() a little Signed-off-by: Matthew Wilcox <willy@linux.intel.com> --- arch/ia64/kernel/perfmon.c | 4 +- fs/proc/array.c | 7 +--- fs/proc/base.c | 2 +- include/linux/sched.h | 15 +++++++ include/linux/wait.h | 11 +++-- kernel/exit.c | 90 +++++++++++++++++++------------------------ kernel/power/process.c | 6 +- kernel/ptrace.c | 8 ++-- kernel/sched.c | 15 +++---- kernel/signal.c | 6 +- kernel/wait.c | 2 +- 11 files changed, 82 insertions(+), 84 deletions(-) diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c index 59169bf..c2ca724 100644 --- a/arch/ia64/kernel/perfmon.c +++ b/arch/ia64/kernel/perfmon.c @@ -2631,7 +2631,7 @@ pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task) */ if (task == current) return 0; - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task)) { DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task_pid_nr(task), task->state)); return -EBUSY; } @@ -4792,7 +4792,7 @@ recheck: * the task must be stopped. */ if (PFM_CMD_STOPPED(cmd)) { - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { + if (!is_task_stopped_or_traced(task)) { DPRINT(("[%d] task not in stopped state\n", task_pid_nr(task))); return -EBUSY; } diff --git a/fs/proc/array.c b/fs/proc/array.c index 63c95af..0bf1fa0 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -141,12 +141,7 @@ static const char *task_state_array[] = { static inline const char *get_task_state(struct task_struct *tsk) { - unsigned int state = (tsk->state & (TASK_RUNNING | - TASK_INTERRUPTIBLE | - TASK_UNINTERRUPTIBLE | - TASK_STOPPED | - TASK_TRACED)) | - tsk->exit_state; + unsigned int state = (tsk->state & TASK_REPORT) | tsk->exit_state; const char **p = &task_state_array[0]; while (state) { diff --git a/fs/proc/base.c b/fs/proc/base.c index aeaf0d0..049a80c 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -199,7 +199,7 @@ static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vf (task == current || \ (task->parent == current && \ (task->ptrace & PT_PTRACED) && \ - (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \ + (is_task_stopped_or_traced(task)) && \ security_ptrace(current,task) == 0)) static int proc_pid_cmdline(struct task_struct *task, char * buffer) diff --git a/include/linux/sched.h b/include/linux/sched.h index 13df99f..fc28637 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -178,6 +178,21 @@ print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) /* in tsk->state again */ #define TASK_DEAD 64 +/* Convenience macros for the sake of wake_up */ +#define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) +#define TASK_ALL (TASK_NORMAL | TASK_STOPPED | TASK_TRACED) + +/* get_task_state() */ +#define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \ + TASK_UNINTERRUPTIBLE | TASK_STOPPED | \ + TASK_TRACED) + +#define is_task_traced(task) ((task->state & TASK_TRACED) != 0) +#define is_task_stopped(task) ((task->state & TASK_STOPPED) != 0) +#define is_task_stopped_or_traced(task) \ + ((task->state & (TASK_STOPPED | TASK_TRACED)) != 0) +#define is_task_loadavg(task) ((task->state & TASK_UNINTERRUPTIBLE) != 0) + #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) #define set_task_state(tsk, state_value) \ diff --git a/include/linux/wait.h b/include/linux/wait.h index 0e68628..0a410a4 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -152,14 +152,15 @@ int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned)); int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned)); wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int)); -#define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL) -#define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL) -#define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL) +#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) +#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) +#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL) +#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL) + #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL) #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL) #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL) -#define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE) -#define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1) +#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1) #define __wait_event(wq, condition) \ do { \ diff --git a/kernel/exit.c b/kernel/exit.c index f1aec27..868ea3e 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -249,7 +249,7 @@ static int has_stopped_jobs(struct pid *pgrp) struct task_struct *p; do_each_pid_task(pgrp, PIDTYPE_PGID, p) { - if (p->state != TASK_STOPPED) + if (!is_task_stopped(p)) continue; retval = 1; break; @@ -614,7 +614,7 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) p->parent = p->real_parent; add_parent(p); - if (p->state == TASK_TRACED) { + if (is_task_traced(p)) { /* * If it was at a trace stop, turn it into * a normal stop since it's no longer being @@ -1387,7 +1387,7 @@ static int wait_task_stopped(struct task_struct *p, int delayed_group_leader, exit_code = p->exit_code; if (unlikely(!exit_code) || - unlikely(p->state & TASK_TRACED)) + unlikely(is_task_traced(p))) goto bail_ref; return wait_noreap_copyout(p, pid, uid, why, (exit_code << 8) | 0x7f, @@ -1565,60 +1565,51 @@ repeat: } allowed = 1; - switch (p->state) { - case TASK_TRACED: - /* - * When we hit the race with PTRACE_ATTACH, - * we will not report this child. But the - * race means it has not yet been moved to - * our ptrace_children list, so we need to - * set the flag here to avoid a spurious ECHILD - * when the race happens with the only child. - */ - flag = 1; - if (!my_ptrace_child(p)) - continue; - /*FALLTHROUGH*/ - case TASK_STOPPED: + if (is_task_stopped_or_traced(p)) { /* * It's stopped now, so it might later * continue, exit, or stop again. + * + * When we hit the race with PTRACE_ATTACH, we + * will not report this child. But the race + * means it has not yet been moved to our + * ptrace_children list, so we need to set the + * flag here to avoid a spurious ECHILD when + * the race happens with the only child. */ flag = 1; - if (!(options & WUNTRACED) && - !my_ptrace_child(p)) - continue; + + if (!my_ptrace_child(p)) { + if (is_task_traced(p)) + continue; + if (!(options & WUNTRACED)) + continue; + } + retval = wait_task_stopped(p, ret == 2, - (options & WNOWAIT), - infop, - stat_addr, ru); + (options & WNOWAIT), infop, + stat_addr, ru); if (retval == -EAGAIN) goto repeat; if (retval != 0) /* He released the lock. */ goto end; - break; - default: - // case EXIT_DEAD: - if (p->exit_state == EXIT_DEAD) + } else if (p->exit_state == EXIT_DEAD) { + continue; + } else if (p->exit_state == EXIT_ZOMBIE) { + /* + * Eligible but we cannot release it yet: + */ + if (ret == 2) + goto check_continued; + if (!likely(options & WEXITED)) continue; - // case EXIT_ZOMBIE: - if (p->exit_state == EXIT_ZOMBIE) { - /* - * Eligible but we cannot release - * it yet: - */ - if (ret == 2) - goto check_continued; - if (!likely(options & WEXITED)) - continue; - retval = wait_task_zombie( - p, (options & WNOWAIT), - infop, stat_addr, ru); - /* He released the lock. */ - if (retval != 0) - goto end; - break; - } + retval = wait_task_zombie(p, + (options & WNOWAIT), infop, + stat_addr, ru); + /* He released the lock. */ + if (retval != 0) + goto end; + } else { check_continued: /* * It's running now, so it might later @@ -1627,12 +1618,11 @@ check_continued: flag = 1; if (!unlikely(options & WCONTINUED)) continue; - retval = wait_task_continued( - p, (options & WNOWAIT), - infop, stat_addr, ru); + retval = wait_task_continued(p, + (options & WNOWAIT), infop, + stat_addr, ru); if (retval != 0) /* He released the lock. */ goto end; - break; } } if (!flag) { diff --git a/kernel/power/process.c b/kernel/power/process.c index 6533923..7710c05 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -86,9 +86,9 @@ static void fake_signal_wake_up(struct task_struct *p, int resume) static void send_fake_signal(struct task_struct *p) { - if (p->state == TASK_STOPPED) + if (is_task_stopped(p)) force_sig_specific(SIGSTOP, p); - fake_signal_wake_up(p, p->state == TASK_STOPPED); + fake_signal_wake_up(p, is_task_stopped(p)); } static int has_mm(struct task_struct *p) @@ -182,7 +182,7 @@ static int try_to_freeze_tasks(int freeze_user_space) if (frozen(p) || !freezeable(p)) continue; - if (p->state == TASK_TRACED && frozen(p->parent)) { + if (is_task_traced(p) && frozen(p->parent)) { cancel_freezing(p); continue; } diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 7c76f2f..9e46a9b 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -51,7 +51,7 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) void ptrace_untrace(struct task_struct *child) { spin_lock(&child->sighand->siglock); - if (child->state == TASK_TRACED) { + if (is_task_traced(child)) { if (child->signal->flags & SIGNAL_STOP_STOPPED) { child->state = TASK_STOPPED; } else { @@ -79,7 +79,7 @@ void __ptrace_unlink(struct task_struct *child) add_parent(child); } - if (child->state == TASK_TRACED) + if (is_task_traced(child)) ptrace_untrace(child); } @@ -103,9 +103,9 @@ int ptrace_check_attach(struct task_struct *child, int kill) && child->signal != NULL) { ret = 0; spin_lock_irq(&child->sighand->siglock); - if (child->state == TASK_STOPPED) { + if (is_task_stopped(child)) { child->state = TASK_TRACED; - } else if (child->state != TASK_TRACED && !kill) { + } else if (!is_task_traced(child) && !kill) { ret = -ESRCH; } spin_unlock_irq(&child->sighand->siglock); diff --git a/kernel/sched.c b/kernel/sched.c index 2810e56..28dde29 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -975,7 +975,7 @@ static int effective_prio(struct task_struct *p) */ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, wakeup); @@ -987,7 +987,7 @@ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) */ static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) { - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible++; dequeue_task(rq, p, sleep); @@ -1623,8 +1623,7 @@ out: int fastcall wake_up_process(struct task_struct *p) { - return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | - TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); + return try_to_wake_up(p, TASK_ALL, 0); } EXPORT_SYMBOL(wake_up_process); @@ -3826,8 +3825,7 @@ void fastcall complete(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done++; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 1, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete); @@ -3838,8 +3836,7 @@ void fastcall complete_all(struct completion *x) spin_lock_irqsave(&x->wait.lock, flags); x->done += UINT_MAX/2; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 0, 0, NULL); + __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete_all); @@ -5237,7 +5234,7 @@ static void activate_idle_task(struct task_struct *p, struct rq *rq) { update_rq_clock(rq); - if (p->state == TASK_UNINTERRUPTIBLE) + if (is_task_loadavg(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, 0); diff --git a/kernel/signal.c b/kernel/signal.c index 1200630..1b08700 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -838,7 +838,7 @@ static inline int wants_signal(int sig, struct task_struct *p) return 0; if (sig == SIGKILL) return 1; - if (p->state & (TASK_STOPPED | TASK_TRACED)) + if (is_task_stopped_or_traced(p)) return 0; return task_curr(p) || !signal_pending(p); } @@ -1441,7 +1441,7 @@ void do_notify_parent(struct task_struct *tsk, int sig) BUG_ON(sig == -1); /* do_notify_parent_cldstop should have been called instead. */ - BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); + BUG_ON(is_task_stopped_or_traced(tsk)); BUG_ON(!tsk->ptrace && (tsk->group_leader != tsk || !thread_group_empty(tsk))); @@ -1729,7 +1729,7 @@ static int do_signal_stop(int signr) * so this check has no races. */ if (!t->exit_state && - !(t->state & (TASK_STOPPED|TASK_TRACED))) { + !is_task_stopped_or_traced(t)) { stop_count++; signal_wake_up(t, 0); } diff --git a/kernel/wait.c b/kernel/wait.c index 444ddbf..f987688 100644 --- a/kernel/wait.c +++ b/kernel/wait.c @@ -215,7 +215,7 @@ void fastcall __wake_up_bit(wait_queue_head_t *wq, void *word, int bit) { struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit); if (waitqueue_active(wq)) - __wake_up(wq, TASK_INTERRUPTIBLE|TASK_UNINTERRUPTIBLE, 1, &key); + __wake_up(wq, TASK_NORMAL, 1, &key); } EXPORT_SYMBOL(__wake_up_bit); -- 1.4.4.2 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-24 12:24 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox @ 2007-10-25 3:31 ` Andrew Morton 2007-10-26 18:45 ` Andrew Morton 2007-12-05 12:56 ` Ingo Molnar 2 siblings, 0 replies; 23+ messages in thread From: Andrew Morton @ 2007-10-25 3:31 UTC (permalink / raw) To: Matthew Wilcox; +Cc: torvalds, linux-kernel, Matthew Wilcox On Wed, 24 Oct 2007 08:24:55 -0400 Matthew Wilcox <matthew@wil.cx> wrote: > Abstracting away direct uses of TASK_ flags allows us to change the > definitions of the task flags more easily. > > Also restructure do_wait() a little umm, spose so. There's an excellent chance that a millionth of our monkeys will come along and wreck this diff during the next two months. In which case I might end up dropping bits of it, we'll see. It would be much better if this patch was a series of patches: one to add the new infrastructure and one-per-subsystem to introduce users of the infrastructure. That way I wouldn't have to go mucking around in the internals of the patch and remembering to tell you when I tossed bits of it out, and which bits those were. This shouldn't come as news to an old-timer :( ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-24 12:24 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 2007-10-25 3:31 ` Andrew Morton @ 2007-10-26 18:45 ` Andrew Morton 2007-10-26 20:39 ` Alexey Dobriyan 2007-12-05 12:56 ` Ingo Molnar 2 siblings, 1 reply; 23+ messages in thread From: Andrew Morton @ 2007-10-26 18:45 UTC (permalink / raw) To: Matthew Wilcox; +Cc: torvalds, linux-kernel, matthew, willy, Stephane Eranian On Wed, 24 Oct 2007 08:24:55 -0400 Matthew Wilcox <matthew@wil.cx> wrote: > Abstracting away direct uses of TASK_ flags allows us to change the > definitions of the task flags more easily. > > Also restructure do_wait() a little > > ... > > diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c > index 59169bf..c2ca724 100644 > --- a/arch/ia64/kernel/perfmon.c > +++ b/arch/ia64/kernel/perfmon.c > @@ -2631,7 +2631,7 @@ pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task) > */ > if (task == current) return 0; > > - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { > + if (!is_task_stopped_or_traced(task)) { > DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task_pid_nr(task), task->state)); > return -EBUSY; > } > @@ -4792,7 +4792,7 @@ recheck: > * the task must be stopped. > */ > if (PFM_CMD_STOPPED(cmd)) { > - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { > + if (!is_task_stopped_or_traced(task)) { > DPRINT(("[%d] task not in stopped state\n", task_pid_nr(task))); > return -EBUSY; > } I have dropped this hunk because the file which it is patching is removed by the (newly-added-to-mm) git-perfmon.patch. I can't immediately find any corresponding code which was readded in a different place by git-perfmon so it looks like this code was simply zapped. Of course, if git-perfmon doesn't merge in 2.6.25 then I'll end up merging your patch but accidentally leaving 2.6.25's arch/ia64/kernel/perfmon.c unpatched. It looks like that'll be non-fatal. This isn't going to go very well and I might end up having to drop this whole patch series and ask for a refactored one. We'll see. ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-26 18:45 ` Andrew Morton @ 2007-10-26 20:39 ` Alexey Dobriyan 2007-10-27 0:33 ` Matthew Wilcox 0 siblings, 1 reply; 23+ messages in thread From: Alexey Dobriyan @ 2007-10-26 20:39 UTC (permalink / raw) To: Andrew Morton Cc: Matthew Wilcox, torvalds, linux-kernel, willy, Stephane Eranian On Fri, Oct 26, 2007 at 11:45:15AM -0700, Andrew Morton wrote: > On Wed, 24 Oct 2007 08:24:55 -0400 > Matthew Wilcox <matthew@wil.cx> wrote: > > > Abstracting away direct uses of TASK_ flags allows us to change the > > definitions of the task flags more easily. > > --- a/arch/ia64/kernel/perfmon.c > > +++ b/arch/ia64/kernel/perfmon.c > > @@ -2631,7 +2631,7 @@ pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task) > > */ > > if (task == current) return 0; > > > > - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { > > + if (!is_task_stopped_or_traced(task)) { > > DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task_pid_nr(task), task->state)); > > return -EBUSY; > > } > > @@ -4792,7 +4792,7 @@ recheck: > > * the task must be stopped. > > */ > > if (PFM_CMD_STOPPED(cmd)) { > > - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { > > + if (!is_task_stopped_or_traced(task)) { ^^^^^^^^^^^^^^^^^^^^^^^^^^ I think this is horrible. Are you going to add full blown static inline function for every combination of state tests? > I have dropped this hunk because the file which it is patching is removed > by the (newly-added-to-mm) git-perfmon.patch. I can't immediately find any > corresponding code which was readded in a different place by git-perfmon so > it looks like this code was simply zapped. > > Of course, if git-perfmon doesn't merge in 2.6.25 then I'll end up merging > your patch but accidentally leaving 2.6.25's arch/ia64/kernel/perfmon.c > unpatched. It looks like that'll be non-fatal. > > This isn't going to go very well and I might end up having to drop this > whole patch series and ask for a refactored one. We'll see. ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-26 20:39 ` Alexey Dobriyan @ 2007-10-27 0:33 ` Matthew Wilcox 0 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-10-27 0:33 UTC (permalink / raw) To: Alexey Dobriyan Cc: Andrew Morton, torvalds, linux-kernel, willy, Stephane Eranian On Sat, Oct 27, 2007 at 12:39:41AM +0400, Alexey Dobriyan wrote: > > > - if ((task->state != TASK_STOPPED) && (task->state != TASK_TRACED)) { > > > + if (!is_task_stopped_or_traced(task)) { > ^^^^^^^^^^^^^^^^^^^^^^^^^^ > > I think this is horrible. Are you going to add full blown static inline > function for every combination of state tests? No, because we don't need them. Just stopped, traced, stopped_or_traced. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-10-24 12:24 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 2007-10-25 3:31 ` Andrew Morton 2007-10-26 18:45 ` Andrew Morton @ 2007-12-05 12:56 ` Ingo Molnar 2007-12-06 14:42 ` Matthew Wilcox 2 siblings, 1 reply; 23+ messages in thread From: Ingo Molnar @ 2007-12-05 12:56 UTC (permalink / raw) To: Matthew Wilcox; +Cc: torvalds, akpm, linux-kernel, Matthew Wilcox * Matthew Wilcox <matthew@wil.cx> wrote: > +#define is_task_stopped(task) ((task->state & TASK_STOPPED) != 0) > +#define is_task_stopped_or_traced(task) \ > + ((task->state & (TASK_STOPPED | TASK_TRACED)) != 0) > +#define is_task_loadavg(task) ((task->state & TASK_UNINTERRUPTIBLE) != 0) 1) please change 'is' and 'task' around so that it reads nicer: if (task_is_stopped(t)) instead of the tongue-twister: if (is_task_stopped(t)) 2) please change task_is_loadavg() to something more sensible - i didnt know what it meant when i first saw it in -mm's sched.c. task_is_uninterruptible() would be the logical choice ... Ingo ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 2/5] Use macros instead of TASK_ flags 2007-12-05 12:56 ` Ingo Molnar @ 2007-12-06 14:42 ` Matthew Wilcox 0 siblings, 0 replies; 23+ messages in thread From: Matthew Wilcox @ 2007-12-06 14:42 UTC (permalink / raw) To: Ingo Molnar; +Cc: torvalds, akpm, linux-kernel, Matthew Wilcox On Wed, Dec 05, 2007 at 01:56:22PM +0100, Ingo Molnar wrote: > 1) please change 'is' and 'task' around so that it reads nicer: > > if (task_is_stopped(t)) > > instead of the tongue-twister: > > if (is_task_stopped(t)) Sure, no problem. I vacillated on this order myself. > 2) please change task_is_loadavg() to something more sensible - i didnt > know what it meant when i first saw it in -mm's sched.c. > task_is_uninterruptible() would be the logical choice ... It's not obvious to me that "can't be interrupted by a signal" is the same thing as "contributes to loadavg". Indeed, I think we would all like to see a day where there's no such thing as an uninterruptible sleep, but we'll still want at least some of those tasks contributing to loadavg. You're right that task_is_loadavg() doesn't make much sense. task_contributes_to_load() is a better name, but only marginally. I've considered task_performing_io(), and name the corresponding bit __TASK_PERFORMING_IO (or even just __TASK_DOING_IO or __TASK_IO), but it's not just doing IO that makes a task contribute to loadavg. I have no good suggestions here ;-( -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." ^ permalink raw reply [flat|nested] 23+ messages in thread
end of thread, other threads:[~2007-12-07 1:49 UTC | newest] Thread overview: 23+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2007-09-02 2:43 [PATCH] TASK_KILLABLE version 2 Matthew Wilcox 2007-09-02 2:46 ` [PATCH 1/5] Use wake_up_locked() in eventpoll Matthew Wilcox 2007-09-02 2:46 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 2007-09-02 2:54 ` Matthew Wilcox 2007-09-02 3:35 ` Daniel Walker 2007-09-02 4:05 ` Matthew Wilcox 2007-09-03 21:03 ` Matthew Wilcox 2007-09-02 2:46 ` [PATCH 3/5] Add TASK_WAKEKILL Matthew Wilcox 2007-09-02 2:46 ` [PATCH 4/5] Add lock_page_killable Matthew Wilcox 2007-09-02 2:46 ` [PATCH 5/5] Make wait_on_retry_sync_kiocb killable Matthew Wilcox 2007-09-24 20:16 ` [PATCH] TASK_KILLABLE version 2 Bob Bell 2007-09-26 11:57 ` Ric Wheeler 2007-09-27 21:47 ` Nick Piggin 2007-12-07 1:49 ` Matthew Wilcox 2007-10-18 22:25 [PATCH 0/5] TASK_KILLABLE Matthew Wilcox 2007-10-18 22:25 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 2007-10-25 3:50 ` Nick Piggin 2007-10-24 12:24 [PATCH 1/5] Use wake_up_locked() in eventpoll Matthew Wilcox 2007-10-24 12:24 ` [PATCH 2/5] Use macros instead of TASK_ flags Matthew Wilcox 2007-10-25 3:31 ` Andrew Morton 2007-10-26 18:45 ` Andrew Morton 2007-10-26 20:39 ` Alexey Dobriyan 2007-10-27 0:33 ` Matthew Wilcox 2007-12-05 12:56 ` Ingo Molnar 2007-12-06 14:42 ` Matthew Wilcox
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