* [PATCH 0/3] sched: fix tg_has_rt_tasks(), tasklist_lock cleanups
@ 2014-09-21 19:33 Oleg Nesterov
2014-09-21 19:33 ` [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() Oleg Nesterov
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Oleg Nesterov @ 2014-09-21 19:33 UTC (permalink / raw)
To: Ingo Molnar, Peter Zijlstra; +Cc: Kirill Tkhai, Mike Galbraith, linux-kernel
This textually depends on
5d07f4202c5d63b73ba1734ed38e08461a689313
"sched: s/do_each_thread/for_each_process_thread/ in core.c"
d38e83c715270cc2e137bbf6f25206c8c023896b
"sched: s/do_each_thread/for_each_process_thread/ in debug.c"
in -tip tree.
Kirill, you seem to agree with 1/3, I'll appreciate your ack.
Oleg.
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() 2014-09-21 19:33 [PATCH 0/3] sched: fix tg_has_rt_tasks(), tasklist_lock cleanups Oleg Nesterov @ 2014-09-21 19:33 ` Oleg Nesterov 2014-09-22 6:54 ` Kirill Tkhai 2014-09-24 14:55 ` [tip:sched/core] sched: Fix " tip-bot for Oleg Nesterov 2014-09-21 19:33 ` [PATCH 2/3] sched: normalize_rt_tasks: don't use _irqsave for tasklist_lock, use task_rq_lock() Oleg Nesterov 2014-09-21 19:33 ` [PATCH 3/3] sched: print_rq: don't use tasklist_lock Oleg Nesterov 2 siblings, 2 replies; 8+ messages in thread From: Oleg Nesterov @ 2014-09-21 19:33 UTC (permalink / raw) To: Ingo Molnar, Peter Zijlstra; +Cc: Kirill Tkhai, Mike Galbraith, linux-kernel tg_has_rt_tasks() wants to find an RT task in this task_group, but task_rq(p)->rt.tg wrongly checks the root rt_rq. Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- kernel/sched/core.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index eee12b3..9023f56 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7354,7 +7354,7 @@ static inline int tg_has_rt_tasks(struct task_group *tg) struct task_struct *g, *p; for_each_process_thread(g, p) { - if (rt_task(p) && task_rq(p)->rt.tg == tg) + if (rt_task(p) && task_group(p) == tg) return 1; } -- 1.5.5.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() 2014-09-21 19:33 ` [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() Oleg Nesterov @ 2014-09-22 6:54 ` Kirill Tkhai 2014-09-24 14:55 ` [tip:sched/core] sched: Fix " tip-bot for Oleg Nesterov 1 sibling, 0 replies; 8+ messages in thread From: Kirill Tkhai @ 2014-09-22 6:54 UTC (permalink / raw) To: Oleg Nesterov; +Cc: Ingo Molnar, Peter Zijlstra, Mike Galbraith, linux-kernel В Вс, 21/09/2014 в 21:33 +0200, Oleg Nesterov пишет: > tg_has_rt_tasks() wants to find an RT task in this task_group, but > task_rq(p)->rt.tg wrongly checks the root rt_rq. > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Kirill Tkhai <ktkhai@parallels.com> > --- > kernel/sched/core.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index eee12b3..9023f56 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -7354,7 +7354,7 @@ static inline int tg_has_rt_tasks(struct task_group *tg) > struct task_struct *g, *p; > > for_each_process_thread(g, p) { > - if (rt_task(p) && task_rq(p)->rt.tg == tg) > + if (rt_task(p) && task_group(p) == tg) > return 1; > } > ^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:sched/core] sched: Fix the task-group check in tg_has_rt_tasks() 2014-09-21 19:33 ` [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() Oleg Nesterov 2014-09-22 6:54 ` Kirill Tkhai @ 2014-09-24 14:55 ` tip-bot for Oleg Nesterov 1 sibling, 0 replies; 8+ messages in thread From: tip-bot for Oleg Nesterov @ 2014-09-24 14:55 UTC (permalink / raw) To: linux-tip-commits Cc: linux-kernel, ktkhai, hpa, mingo, peterz, umgwanakikbuti, tglx, oleg Commit-ID: 8651c65844e93af44554272b7e0d2b142837b244 Gitweb: http://git.kernel.org/tip/8651c65844e93af44554272b7e0d2b142837b244 Author: Oleg Nesterov <oleg@redhat.com> AuthorDate: Sun, 21 Sep 2014 21:33:36 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Wed, 24 Sep 2014 14:47:00 +0200 sched: Fix the task-group check in tg_has_rt_tasks() tg_has_rt_tasks() wants to find an RT task in this task_group, but task_rq(p)->rt.tg wrongly checks the root rt_rq. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Kirill Tkhai <ktkhai@parallels.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Link: http://lkml.kernel.org/r/20140921193336.GA28618@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 09bde2a..0abfb7e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7441,7 +7441,7 @@ static inline int tg_has_rt_tasks(struct task_group *tg) struct task_struct *g, *p; for_each_process_thread(g, p) { - if (rt_task(p) && task_rq(p)->rt.tg == tg) + if (rt_task(p) && task_group(p) == tg) return 1; } ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 2/3] sched: normalize_rt_tasks: don't use _irqsave for tasklist_lock, use task_rq_lock() 2014-09-21 19:33 [PATCH 0/3] sched: fix tg_has_rt_tasks(), tasklist_lock cleanups Oleg Nesterov 2014-09-21 19:33 ` [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() Oleg Nesterov @ 2014-09-21 19:33 ` Oleg Nesterov 2014-09-24 14:56 ` [tip:sched/core] sched: normalize_rt_tasks(): Don' t " tip-bot for Oleg Nesterov 2014-09-21 19:33 ` [PATCH 3/3] sched: print_rq: don't use tasklist_lock Oleg Nesterov 2 siblings, 1 reply; 8+ messages in thread From: Oleg Nesterov @ 2014-09-21 19:33 UTC (permalink / raw) To: Ingo Molnar, Peter Zijlstra; +Cc: Kirill Tkhai, Mike Galbraith, linux-kernel 1. read_lock(tasklist_lock) does not need to disable irqs. 2. ->mm != NULL is the common mistake, use PF_KTHREAD. 3. The second ->mm check can be simply removed. 4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) + __task_rq_lock(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- kernel/sched/core.c | 16 ++++++---------- 1 files changed, 6 insertions(+), 10 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8a6506f..eee12b3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7137,12 +7137,12 @@ void normalize_rt_tasks(void) unsigned long flags; struct rq *rq; - read_lock_irqsave(&tasklist_lock, flags); + read_lock(&tasklist_lock); for_each_process_thread(g, p) { /* * Only normalize user tasks: */ - if (!p->mm) + if (p->flags & PF_KTHREAD) continue; p->se.exec_start = 0; @@ -7157,20 +7157,16 @@ void normalize_rt_tasks(void) * Renice negative nice level userspace * tasks back to 0: */ - if (task_nice(p) < 0 && p->mm) + if (task_nice(p) < 0) set_user_nice(p, 0); continue; } - raw_spin_lock(&p->pi_lock); - rq = __task_rq_lock(p); - + rq = task_rq_lock(p, &flags); normalize_task(rq, p); - - __task_rq_unlock(rq); - raw_spin_unlock(&p->pi_lock); + task_rq_unlock(rq, p, &flags); } - read_unlock_irqrestore(&tasklist_lock, flags); + read_unlock(&tasklist_lock); } #endif /* CONFIG_MAGIC_SYSRQ */ -- 1.5.5.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [tip:sched/core] sched: normalize_rt_tasks(): Don' t use _irqsave for tasklist_lock, use task_rq_lock() 2014-09-21 19:33 ` [PATCH 2/3] sched: normalize_rt_tasks: don't use _irqsave for tasklist_lock, use task_rq_lock() Oleg Nesterov @ 2014-09-24 14:56 ` tip-bot for Oleg Nesterov 0 siblings, 0 replies; 8+ messages in thread From: tip-bot for Oleg Nesterov @ 2014-09-24 14:56 UTC (permalink / raw) To: linux-tip-commits Cc: linux-kernel, hpa, mingo, torvalds, peterz, umgwanakikbuti, tkhai, tglx, oleg Commit-ID: 3472eaa1f12e217e2b8b0ef658ff861b2308cbbd Gitweb: http://git.kernel.org/tip/3472eaa1f12e217e2b8b0ef658ff861b2308cbbd Author: Oleg Nesterov <oleg@redhat.com> AuthorDate: Sun, 21 Sep 2014 21:33:38 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Wed, 24 Sep 2014 14:47:03 +0200 sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock() 1. read_lock(tasklist_lock) does not need to disable irqs. 2. ->mm != NULL is a common mistake, use PF_KTHREAD. 3. The second ->mm check can be simply removed. 4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) + __task_rq_lock(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/core.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0abfb7e..d65566d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7220,12 +7220,12 @@ void normalize_rt_tasks(void) unsigned long flags; struct rq *rq; - read_lock_irqsave(&tasklist_lock, flags); + read_lock(&tasklist_lock); for_each_process_thread(g, p) { /* * Only normalize user tasks: */ - if (!p->mm) + if (p->flags & PF_KTHREAD) continue; p->se.exec_start = 0; @@ -7240,20 +7240,16 @@ void normalize_rt_tasks(void) * Renice negative nice level userspace * tasks back to 0: */ - if (task_nice(p) < 0 && p->mm) + if (task_nice(p) < 0) set_user_nice(p, 0); continue; } - raw_spin_lock(&p->pi_lock); - rq = __task_rq_lock(p); - + rq = task_rq_lock(p, &flags); normalize_task(rq, p); - - __task_rq_unlock(rq); - raw_spin_unlock(&p->pi_lock); + task_rq_unlock(rq, p, &flags); } - read_unlock_irqrestore(&tasklist_lock, flags); + read_unlock(&tasklist_lock); } #endif /* CONFIG_MAGIC_SYSRQ */ ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 3/3] sched: print_rq: don't use tasklist_lock 2014-09-21 19:33 [PATCH 0/3] sched: fix tg_has_rt_tasks(), tasklist_lock cleanups Oleg Nesterov 2014-09-21 19:33 ` [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() Oleg Nesterov 2014-09-21 19:33 ` [PATCH 2/3] sched: normalize_rt_tasks: don't use _irqsave for tasklist_lock, use task_rq_lock() Oleg Nesterov @ 2014-09-21 19:33 ` Oleg Nesterov 2014-09-24 14:56 ` [tip:sched/core] sched: print_rq(): Don't " tip-bot for Oleg Nesterov 2 siblings, 1 reply; 8+ messages in thread From: Oleg Nesterov @ 2014-09-21 19:33 UTC (permalink / raw) To: Ingo Molnar, Peter Zijlstra; +Cc: Kirill Tkhai, Mike Galbraith, linux-kernel read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do not need to disable irqs, and they are already disabled by the caller. And afaics this lock buys nothing, we can rely on rcu_read_lock(). In this case it makes sense to also move rcu_read_lock/unlock from the caller to print_rq(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- kernel/sched/debug.c | 7 ++----- 1 files changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index c7fe1ea..ce33780 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -150,7 +150,6 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) { struct task_struct *g, *p; - unsigned long flags; SEQ_printf(m, "\nrunnable tasks:\n" @@ -159,14 +158,14 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) "------------------------------------------------------" "----------------------------------------------------\n"); - read_lock_irqsave(&tasklist_lock, flags); + rcu_read_lock(); for_each_process_thread(g, p) { if (task_cpu(p) != rq_cpu) continue; print_task(m, rq, p); } - read_unlock_irqrestore(&tasklist_lock, flags); + rcu_read_unlock(); } void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) @@ -331,9 +330,7 @@ do { \ print_cfs_stats(m, cpu); print_rt_stats(m, cpu); - rcu_read_lock(); print_rq(m, rq, cpu); - rcu_read_unlock(); spin_unlock_irqrestore(&sched_debug_lock, flags); SEQ_printf(m, "\n"); } -- 1.5.5.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [tip:sched/core] sched: print_rq(): Don't use tasklist_lock 2014-09-21 19:33 ` [PATCH 3/3] sched: print_rq: don't use tasklist_lock Oleg Nesterov @ 2014-09-24 14:56 ` tip-bot for Oleg Nesterov 0 siblings, 0 replies; 8+ messages in thread From: tip-bot for Oleg Nesterov @ 2014-09-24 14:56 UTC (permalink / raw) To: linux-tip-commits Cc: linux-kernel, hpa, mingo, torvalds, peterz, umgwanakikbuti, tkhai, tglx, oleg Commit-ID: 5bd96ab6fef66ec6b9f54134364e618fd0f8f2f3 Gitweb: http://git.kernel.org/tip/5bd96ab6fef66ec6b9f54134364e618fd0f8f2f3 Author: Oleg Nesterov <oleg@redhat.com> AuthorDate: Sun, 21 Sep 2014 21:33:41 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Wed, 24 Sep 2014 14:47:04 +0200 sched: print_rq(): Don't use tasklist_lock read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do not need to disable irqs, and they are already disabled by the caller. And afaics this lock buys nothing, we can rely on rcu_read_lock(). In this case it makes sense to also move rcu_read_lock/unlock from the caller to print_rq(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921193341.GA28628@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/debug.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index c7fe1ea0..ce33780 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -150,7 +150,6 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) { struct task_struct *g, *p; - unsigned long flags; SEQ_printf(m, "\nrunnable tasks:\n" @@ -159,14 +158,14 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) "------------------------------------------------------" "----------------------------------------------------\n"); - read_lock_irqsave(&tasklist_lock, flags); + rcu_read_lock(); for_each_process_thread(g, p) { if (task_cpu(p) != rq_cpu) continue; print_task(m, rq, p); } - read_unlock_irqrestore(&tasklist_lock, flags); + rcu_read_unlock(); } void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) @@ -331,9 +330,7 @@ do { \ print_cfs_stats(m, cpu); print_rt_stats(m, cpu); - rcu_read_lock(); print_rq(m, rq, cpu); - rcu_read_unlock(); spin_unlock_irqrestore(&sched_debug_lock, flags); SEQ_printf(m, "\n"); } ^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2014-09-24 15:06 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2014-09-21 19:33 [PATCH 0/3] sched: fix tg_has_rt_tasks(), tasklist_lock cleanups Oleg Nesterov 2014-09-21 19:33 ` [PATCH 1/3] sched: fix the task-group check in tg_has_rt_tasks() Oleg Nesterov 2014-09-22 6:54 ` Kirill Tkhai 2014-09-24 14:55 ` [tip:sched/core] sched: Fix " tip-bot for Oleg Nesterov 2014-09-21 19:33 ` [PATCH 2/3] sched: normalize_rt_tasks: don't use _irqsave for tasklist_lock, use task_rq_lock() Oleg Nesterov 2014-09-24 14:56 ` [tip:sched/core] sched: normalize_rt_tasks(): Don' t " tip-bot for Oleg Nesterov 2014-09-21 19:33 ` [PATCH 3/3] sched: print_rq: don't use tasklist_lock Oleg Nesterov 2014-09-24 14:56 ` [tip:sched/core] sched: print_rq(): Don't " tip-bot for Oleg Nesterov
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