From 072ba49838b42c873c496d72c91bb237914cf3b6 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Sun, 26 Oct 2008 15:26:57 -0700 Subject: ftrace: fix breakage in bin_fmt results In 777e208d40d0953efc6fb4ab58590da3f7d8f02d we changed from outputting field->cpu (a char) to iter->cpu (unsigned int), increasing the resulting structure size by 3 bytes. Signed-off-by: Eric Anholt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9f3b478f9171..974973e39e87 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1755,7 +1755,7 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter) return TRACE_TYPE_HANDLED; SEQ_PUT_FIELD_RET(s, entry->pid); - SEQ_PUT_FIELD_RET(s, iter->cpu); + SEQ_PUT_FIELD_RET(s, entry->cpu); SEQ_PUT_FIELD_RET(s, iter->ts); switch (entry->type) { -- cgit v1.2.3 From f4b6755fb37595da3630d1d6fc130ea6888cd48f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 4 Nov 2008 21:25:07 +0100 Subject: sched: cleanup fair task selection Impact: cleanup Clean up task selection Signed-off-by: Peter Zijlstra Acked-by: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 33 +++++++++++---------------------- 1 file changed, 11 insertions(+), 22 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ce514afd78ff..6167336a2372 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -347,17 +347,17 @@ static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) rb_erase(&se->run_node, &cfs_rq->tasks_timeline); } -static inline struct rb_node *first_fair(struct cfs_rq *cfs_rq) -{ - return cfs_rq->rb_leftmost; -} - static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq) { - return rb_entry(first_fair(cfs_rq), struct sched_entity, run_node); + struct rb_node *left = cfs_rq->rb_leftmost; + + if (!left) + return NULL; + + return rb_entry(left, struct sched_entity, run_node); } -static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) +static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) { struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); @@ -794,28 +794,16 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) static int wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); -static struct sched_entity * -pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se) +static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) { + struct sched_entity *se = __pick_next_entity(cfs_rq); + if (!cfs_rq->next || wakeup_preempt_entity(cfs_rq->next, se) == 1) return se; return cfs_rq->next; } -static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) -{ - struct sched_entity *se = NULL; - - if (first_fair(cfs_rq)) { - se = __pick_next_entity(cfs_rq); - se = pick_next(cfs_rq, se); - set_next_entity(cfs_rq, se); - } - - return se; -} - static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) { /* @@ -1396,6 +1384,7 @@ static struct task_struct *pick_next_task_fair(struct rq *rq) do { se = pick_next_entity(cfs_rq); + set_next_entity(cfs_rq, se); cfs_rq = group_cfs_rq(se); } while (cfs_rq); -- cgit v1.2.3 From d95f98d0691d3aba5e35850011946a08c9b36428 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 4 Nov 2008 21:25:08 +0100 Subject: sched: fix fair preempt check Impact: fix cross-class preemption Inter-class wakeup preemptions should go on class order. Signed-off-by: Peter Zijlstra Acked-by: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 6167336a2372..ebd6de8d17fd 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1329,6 +1329,9 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync) return; } + if (unlikely(p->sched_class != &fair_sched_class)) + return; + if (unlikely(se == pse)) return; -- cgit v1.2.3 From 4793241be408b3926ee00c704d7da3b3faf3a05f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 4 Nov 2008 21:25:09 +0100 Subject: sched: backward looking buddy Impact: improve/change/fix wakeup-buddy scheduling Currently we only have a forward looking buddy, that is, we prefer to schedule to the task we last woke up, under the presumption that its going to consume the data we just produced, and therefore will have cache hot benefits. This allows co-waking producer/consumer task pairs to run ahead of the pack for a little while, keeping their cache warm. Without this, we would interleave all pairs, utterly trashing the cache. This patch introduces a backward looking buddy, that is, suppose that in the above scenario, the consumer preempts the producer before it can go to sleep, we will therefore miss the wakeup from consumer to producer (its already running, after all), breaking the cycle and reverting to the cache-trashing interleaved schedule pattern. The backward buddy will try to schedule back to the task that woke us up in case the forward buddy is not available, under the assumption that the last task will be the one with the most cache hot task around barring current. This will basically allow a task to continue after it got preempted. In order to avoid starvation, we allow either buddy to get wakeup_gran ahead of the pack. Signed-off-by: Peter Zijlstra Acked-by: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++-- kernel/sched_fair.c | 32 +++++++++++++++++++++++++------- kernel/sched_features.h | 1 + 3 files changed, 30 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index e8819bc6f462..82cc839c9210 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -397,7 +397,7 @@ struct cfs_rq { * 'curr' points to currently running entity on this cfs_rq. * It is set to NULL otherwise (i.e when none are currently running). */ - struct sched_entity *curr, *next; + struct sched_entity *curr, *next, *last; unsigned long nr_spread_over; @@ -1805,7 +1805,9 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) /* * Buddy candidates are cache hot: */ - if (sched_feat(CACHE_HOT_BUDDY) && (&p->se == cfs_rq_of(&p->se)->next)) + if (sched_feat(CACHE_HOT_BUDDY) && + (&p->se == cfs_rq_of(&p->se)->next || + &p->se == cfs_rq_of(&p->se)->last)) return 1; if (p->sched_class != &fair_sched_class) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ebd6de8d17fd..a6b1db8a0bd8 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -341,9 +341,6 @@ static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) cfs_rq->rb_leftmost = next_node; } - if (cfs_rq->next == se) - cfs_rq->next = NULL; - rb_erase(&se->run_node, &cfs_rq->tasks_timeline); } @@ -741,6 +738,12 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) #endif } + if (cfs_rq->last == se) + cfs_rq->last = NULL; + + if (cfs_rq->next == se) + cfs_rq->next = NULL; + if (se != cfs_rq->curr) __dequeue_entity(cfs_rq, se); account_entity_dequeue(cfs_rq, se); @@ -798,10 +801,13 @@ static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) { struct sched_entity *se = __pick_next_entity(cfs_rq); - if (!cfs_rq->next || wakeup_preempt_entity(cfs_rq->next, se) == 1) - return se; + if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, se) < 1) + return cfs_rq->next; - return cfs_rq->next; + if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, se) < 1) + return cfs_rq->last; + + return se; } static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) @@ -1319,10 +1325,11 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync) { struct task_struct *curr = rq->curr; - struct cfs_rq *cfs_rq = task_cfs_rq(curr); struct sched_entity *se = &curr->se, *pse = &p->se; if (unlikely(rt_prio(p->prio))) { + struct cfs_rq *cfs_rq = task_cfs_rq(curr); + update_rq_clock(rq); update_curr(cfs_rq); resched_task(curr); @@ -1335,6 +1342,17 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync) if (unlikely(se == pse)) return; + /* + * Only set the backward buddy when the current task is still on the + * rq. This can happen when a wakeup gets interleaved with schedule on + * the ->pre_schedule() or idle_balance() point, either of which can + * drop the rq lock. + * + * Also, during early boot the idle thread is in the fair class, for + * obvious reasons its a bad idea to schedule back to the idle thread. + */ + if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle)) + cfs_rq_of(se)->last = se; cfs_rq_of(pse)->next = pse; /* diff --git a/kernel/sched_features.h b/kernel/sched_features.h index fda016218296..da5d93b5d2c6 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -12,3 +12,4 @@ SCHED_FEAT(LB_BIAS, 1) SCHED_FEAT(LB_WAKEUP_UPDATE, 1) SCHED_FEAT(ASYM_EFF_LOAD, 1) SCHED_FEAT(WAKEUP_OVERLAP, 0) +SCHED_FEAT(LAST_BUDDY, 1) -- cgit v1.2.3 From 02479099c286894644f8e96c6bbb535ab64662fd Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 4 Nov 2008 21:25:10 +0100 Subject: sched: fix buddies for group scheduling Impact: scheduling order fix for group scheduling For each level in the hierarchy, set the buddy to point to the right entity. Therefore, when we do the hierarchical schedule, we have a fair chance of ending up where we meant to. Signed-off-by: Peter Zijlstra Acked-by: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index a6b1db8a0bd8..51aa3e102acb 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1319,6 +1319,18 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) return 0; } +static void set_last_buddy(struct sched_entity *se) +{ + for_each_sched_entity(se) + cfs_rq_of(se)->last = se; +} + +static void set_next_buddy(struct sched_entity *se) +{ + for_each_sched_entity(se) + cfs_rq_of(se)->next = se; +} + /* * Preempt the current task with a newly woken task if needed: */ @@ -1352,8 +1364,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync) * obvious reasons its a bad idea to schedule back to the idle thread. */ if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle)) - cfs_rq_of(se)->last = se; - cfs_rq_of(pse)->next = pse; + set_last_buddy(se); + set_next_buddy(pse); /* * We can come here with TIF_NEED_RESCHED already set from new task -- cgit v1.2.3 From 561920a0d2bb6d63343e83acfd784c0a77bd28d1 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Thu, 30 Oct 2008 18:28:41 +0100 Subject: generic-ipi: fix the smp_mb() placement smp_mb() is needed (to make the memory operations visible globally) before sending the ipi on the sender and the receiver (on Alpha atleast) needs smp_read_barrier_depends() in the handler before reading the call_single_queue list in a lock-free fashion. On x86, x2apic mode register accesses for sending IPI's don't have serializing semantics. So the need for smp_mb() before sending the IPI becomes more critical in x2apic mode. Remove the unnecessary smp_mb() in csd_flag_wait(), as the presence of that smp_mb() doesn't mean anything on the sender, when the ipi receiver is not doing any thing special (like memory fence) after clearing the CSD_FLAG_WAIT. Signed-off-by: Suresh Siddha Signed-off-by: Jens Axboe --- kernel/smp.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index f362a8553777..75c8dde58c55 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -51,10 +51,6 @@ static void csd_flag_wait(struct call_single_data *data) { /* Wait for response */ do { - /* - * We need to see the flags store in the IPI handler - */ - smp_mb(); if (!(data->flags & CSD_FLAG_WAIT)) break; cpu_relax(); @@ -76,6 +72,11 @@ static void generic_exec_single(int cpu, struct call_single_data *data) list_add_tail(&data->list, &dst->list); spin_unlock_irqrestore(&dst->lock, flags); + /* + * Make the list addition visible before sending the ipi. + */ + smp_mb(); + if (ipi) arch_send_call_function_single_ipi(cpu); @@ -157,7 +158,7 @@ void generic_smp_call_function_single_interrupt(void) * Need to see other stores to list head for checking whether * list is empty without holding q->lock */ - smp_mb(); + smp_read_barrier_depends(); while (!list_empty(&q->list)) { unsigned int data_flags; @@ -191,7 +192,7 @@ void generic_smp_call_function_single_interrupt(void) /* * See comment on outer loop */ - smp_mb(); + smp_read_barrier_depends(); } } @@ -370,6 +371,11 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info, list_add_tail_rcu(&data->csd.list, &call_function_queue); spin_unlock_irqrestore(&call_function_lock, flags); + /* + * Make the list addition visible before sending the ipi. + */ + smp_mb(); + /* Send a message to all CPUs in the map */ arch_send_call_function_ipi(mask); -- cgit v1.2.3 From 9c133c469d38043d5aadaa03f2fb840d88d1cf4f Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 6 Nov 2008 08:42:48 +0100 Subject: Add round_jiffies_up and related routines This patch (as1158b) adds round_jiffies_up() and friends. These routines work like the analogous round_jiffies() functions, except that they will never round down. The new routines will be useful for timeouts where we don't care exactly when the timer expires, provided it doesn't expire too soon. Signed-off-by: Alan Stern Signed-off-by: Jens Axboe --- include/linux/timer.h | 5 ++ kernel/timer.c | 129 ++++++++++++++++++++++++++++++++++++++------------ 2 files changed, 104 insertions(+), 30 deletions(-) (limited to 'kernel') diff --git a/include/linux/timer.h b/include/linux/timer.h index d4ba79248a27..daf9685b861c 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -186,4 +186,9 @@ unsigned long __round_jiffies_relative(unsigned long j, int cpu); unsigned long round_jiffies(unsigned long j); unsigned long round_jiffies_relative(unsigned long j); +unsigned long __round_jiffies_up(unsigned long j, int cpu); +unsigned long __round_jiffies_up_relative(unsigned long j, int cpu); +unsigned long round_jiffies_up(unsigned long j); +unsigned long round_jiffies_up_relative(unsigned long j); + #endif diff --git a/kernel/timer.c b/kernel/timer.c index 56becf373c58..dbd50fabe4c7 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -112,27 +112,8 @@ timer_set_base(struct timer_list *timer, struct tvec_base *new_base) tbase_get_deferrable(timer->base)); } -/** - * __round_jiffies - function to round jiffies to a full second - * @j: the time in (absolute) jiffies that should be rounded - * @cpu: the processor number on which the timeout will happen - * - * __round_jiffies() rounds an absolute time in the future (in jiffies) - * up or down to (approximately) full seconds. This is useful for timers - * for which the exact time they fire does not matter too much, as long as - * they fire approximately every X seconds. - * - * By rounding these timers to whole seconds, all such timers will fire - * at the same time, rather than at various times spread out. The goal - * of this is to have the CPU wake up less, which saves power. - * - * The exact rounding is skewed for each processor to avoid all - * processors firing at the exact same time, which could lead - * to lock contention or spurious cache line bouncing. - * - * The return value is the rounded version of the @j parameter. - */ -unsigned long __round_jiffies(unsigned long j, int cpu) +static unsigned long round_jiffies_common(unsigned long j, int cpu, + bool force_up) { int rem; unsigned long original = j; @@ -154,8 +135,9 @@ unsigned long __round_jiffies(unsigned long j, int cpu) * due to delays of the timer irq, long irq off times etc etc) then * we should round down to the whole second, not up. Use 1/4th second * as cutoff for this rounding as an extreme upper bound for this. + * But never round down if @force_up is set. */ - if (rem < HZ/4) /* round down */ + if (rem < HZ/4 && !force_up) /* round down */ j = j - rem; else /* round up */ j = j - rem + HZ; @@ -167,6 +149,31 @@ unsigned long __round_jiffies(unsigned long j, int cpu) return original; return j; } + +/** + * __round_jiffies - function to round jiffies to a full second + * @j: the time in (absolute) jiffies that should be rounded + * @cpu: the processor number on which the timeout will happen + * + * __round_jiffies() rounds an absolute time in the future (in jiffies) + * up or down to (approximately) full seconds. This is useful for timers + * for which the exact time they fire does not matter too much, as long as + * they fire approximately every X seconds. + * + * By rounding these timers to whole seconds, all such timers will fire + * at the same time, rather than at various times spread out. The goal + * of this is to have the CPU wake up less, which saves power. + * + * The exact rounding is skewed for each processor to avoid all + * processors firing at the exact same time, which could lead + * to lock contention or spurious cache line bouncing. + * + * The return value is the rounded version of the @j parameter. + */ +unsigned long __round_jiffies(unsigned long j, int cpu) +{ + return round_jiffies_common(j, cpu, false); +} EXPORT_SYMBOL_GPL(__round_jiffies); /** @@ -191,13 +198,10 @@ EXPORT_SYMBOL_GPL(__round_jiffies); */ unsigned long __round_jiffies_relative(unsigned long j, int cpu) { - /* - * In theory the following code can skip a jiffy in case jiffies - * increments right between the addition and the later subtraction. - * However since the entire point of this function is to use approximate - * timeouts, it's entirely ok to not handle that. - */ - return __round_jiffies(j + jiffies, cpu) - jiffies; + unsigned long j0 = jiffies; + + /* Use j0 because jiffies might change while we run */ + return round_jiffies_common(j + j0, cpu, false) - j0; } EXPORT_SYMBOL_GPL(__round_jiffies_relative); @@ -218,7 +222,7 @@ EXPORT_SYMBOL_GPL(__round_jiffies_relative); */ unsigned long round_jiffies(unsigned long j) { - return __round_jiffies(j, raw_smp_processor_id()); + return round_jiffies_common(j, raw_smp_processor_id(), false); } EXPORT_SYMBOL_GPL(round_jiffies); @@ -243,6 +247,71 @@ unsigned long round_jiffies_relative(unsigned long j) } EXPORT_SYMBOL_GPL(round_jiffies_relative); +/** + * __round_jiffies_up - function to round jiffies up to a full second + * @j: the time in (absolute) jiffies that should be rounded + * @cpu: the processor number on which the timeout will happen + * + * This is the same as __round_jiffies() except that it will never + * round down. This is useful for timeouts for which the exact time + * of firing does not matter too much, as long as they don't fire too + * early. + */ +unsigned long __round_jiffies_up(unsigned long j, int cpu) +{ + return round_jiffies_common(j, cpu, true); +} +EXPORT_SYMBOL_GPL(__round_jiffies_up); + +/** + * __round_jiffies_up_relative - function to round jiffies up to a full second + * @j: the time in (relative) jiffies that should be rounded + * @cpu: the processor number on which the timeout will happen + * + * This is the same as __round_jiffies_relative() except that it will never + * round down. This is useful for timeouts for which the exact time + * of firing does not matter too much, as long as they don't fire too + * early. + */ +unsigned long __round_jiffies_up_relative(unsigned long j, int cpu) +{ + unsigned long j0 = jiffies; + + /* Use j0 because jiffies might change while we run */ + return round_jiffies_common(j + j0, cpu, true) - j0; +} +EXPORT_SYMBOL_GPL(__round_jiffies_up_relative); + +/** + * round_jiffies_up - function to round jiffies up to a full second + * @j: the time in (absolute) jiffies that should be rounded + * + * This is the same as round_jiffies() except that it will never + * round down. This is useful for timeouts for which the exact time + * of firing does not matter too much, as long as they don't fire too + * early. + */ +unsigned long round_jiffies_up(unsigned long j) +{ + return round_jiffies_common(j, raw_smp_processor_id(), true); +} +EXPORT_SYMBOL_GPL(round_jiffies_up); + +/** + * round_jiffies_up_relative - function to round jiffies up to a full second + * @j: the time in (relative) jiffies that should be rounded + * + * This is the same as round_jiffies_relative() except that it will never + * round down. This is useful for timeouts for which the exact time + * of firing does not matter too much, as long as they don't fire too + * early. + */ +unsigned long round_jiffies_up_relative(unsigned long j) +{ + return __round_jiffies_up_relative(j, raw_smp_processor_id()); +} +EXPORT_SYMBOL_GPL(round_jiffies_up_relative); + static inline void set_running_timer(struct tvec_base *base, struct timer_list *timer) -- cgit v1.2.3 From 2d3854a37e8b767a51aba38ed6d22817b0631e33 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 5 Nov 2008 13:39:10 +1100 Subject: cpumask: introduce new API, without changing anything Impact: introduce new APIs We want to deprecate cpumasks on the stack, as we are headed for gynormous numbers of CPUs. Eventually, we want to head towards an undefined 'struct cpumask' so they can never be declared on stack. 1) New cpumask functions which take pointers instead of copies. (cpus_* -> cpumask_*) 2) Several new helpers to reduce requirements for temporary cpumasks (cpumask_first_and, cpumask_next_and, cpumask_any_and) 3) Helpers for declaring cpumasks on or offstack for large NR_CPUS (cpumask_var_t, alloc_cpumask_var and free_cpumask_var) 4) 'struct cpumask' for explicitness and to mark new-style code. 5) Make iterator functions stop at nr_cpu_ids (a runtime constant), not NR_CPUS for time efficiency and for smaller dynamic allocations in future. 6) cpumask_copy() so we can allocate less than a full cpumask eventually (for alloc_cpumask_var), and so we can eliminate the 'struct cpumask' definition eventually. 7) work_on_cpu() helper for doing task on a CPU, rather than saving old cpumask for current thread and manipulating it. 8) smp_call_function_many() which is smp_call_function_mask() except taking a cpumask pointer. Note that this patch simply introduces the new functions and leaves the obsolescent ones in place. This is to simplify the transition patches. Signed-off-by: Rusty Russell Signed-off-by: Ingo Molnar --- include/linux/cpumask.h | 502 +++++++++++++++++++++++++++++++++++++++++++++- include/linux/smp.h | 9 + include/linux/workqueue.h | 8 + kernel/cpu.c | 3 + kernel/workqueue.c | 45 +++++ lib/cpumask.c | 73 +++++++ 6 files changed, 638 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index d3219d73f8e6..c8e66619097b 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -5,6 +5,9 @@ * Cpumasks provide a bitmap suitable for representing the * set of CPU's in a system, one bit position per CPU number. * + * The new cpumask_ ops take a "struct cpumask *"; the old ones + * use cpumask_t. + * * See detailed comments in the file linux/bitmap.h describing the * data type on which these cpumasks are based. * @@ -31,7 +34,7 @@ * will span the entire range of NR_CPUS. * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * - * The available cpumask operations are: + * The obsolescent cpumask operations are: * * void cpu_set(cpu, mask) turn on bit 'cpu' in mask * void cpu_clear(cpu, mask) turn off bit 'cpu' in mask @@ -138,7 +141,7 @@ #include #include -typedef struct { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t; +typedef struct cpumask { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t; extern cpumask_t _unused_cpumask_arg_; #define cpu_set(cpu, dst) __cpu_set((cpu), &(dst)) @@ -527,4 +530,499 @@ extern cpumask_t cpu_active_map; #define for_each_online_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_online_map) #define for_each_present_cpu(cpu) for_each_cpu_mask_nr((cpu), cpu_present_map) +/* These are the new versions of the cpumask operators: passed by pointer. + * The older versions will be implemented in terms of these, then deleted. */ +#define cpumask_bits(maskp) ((maskp)->bits) + +#if NR_CPUS <= BITS_PER_LONG +#define CPU_BITS_ALL \ +{ \ + [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \ +} + +/* This produces more efficient code. */ +#define nr_cpumask_bits NR_CPUS + +#else /* NR_CPUS > BITS_PER_LONG */ + +#define CPU_BITS_ALL \ +{ \ + [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL, \ + [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \ +} + +#define nr_cpumask_bits nr_cpu_ids +#endif /* NR_CPUS > BITS_PER_LONG */ + +/* verify cpu argument to cpumask_* operators */ +static inline unsigned int cpumask_check(unsigned int cpu) +{ +#ifdef CONFIG_DEBUG_PER_CPU_MAPS + WARN_ON_ONCE(cpu >= nr_cpumask_bits); +#endif /* CONFIG_DEBUG_PER_CPU_MAPS */ + return cpu; +} + +#if NR_CPUS == 1 +/* Uniprocesor. */ +#define cpumask_first(src) ({ (void)(src); 0; }) +#define cpumask_next(n, src) ({ (void)(src); 1; }) +#define cpumask_next_zero(n, src) ({ (void)(src); 1; }) +#define cpumask_next_and(n, srcp, andp) ({ (void)(srcp), (void)(andp); 1; }) +#define cpumask_any_but(mask, cpu) ({ (void)(mask); (void)(cpu); 0; }) + +#define for_each_cpu(cpu, mask) \ + for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) +#define for_each_cpu_and(cpu, mask, and) \ + for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask, (void)and) +#else +/** + * cpumask_first - get the first cpu in a cpumask + * @srcp: the cpumask pointer + * + * Returns >= nr_cpu_ids if no cpus set. + */ +static inline unsigned int cpumask_first(const struct cpumask *srcp) +{ + return find_first_bit(cpumask_bits(srcp), nr_cpumask_bits); +} + +/** + * cpumask_next - get the next cpu in a cpumask + * @n: the cpu prior to the place to search (ie. return will be > @n) + * @srcp: the cpumask pointer + * + * Returns >= nr_cpu_ids if no further cpus set. + */ +static inline unsigned int cpumask_next(int n, const struct cpumask *srcp) +{ + /* -1 is a legal arg here. */ + if (n != -1) + cpumask_check(n); + return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1); +} + +/** + * cpumask_next_zero - get the next unset cpu in a cpumask + * @n: the cpu prior to the place to search (ie. return will be > @n) + * @srcp: the cpumask pointer + * + * Returns >= nr_cpu_ids if no further cpus unset. + */ +static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp) +{ + /* -1 is a legal arg here. */ + if (n != -1) + cpumask_check(n); + return find_next_zero_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1); +} + +int cpumask_next_and(int n, const struct cpumask *, const struct cpumask *); +int cpumask_any_but(const struct cpumask *mask, unsigned int cpu); + +#define for_each_cpu(cpu, mask) \ + for ((cpu) = -1; \ + (cpu) = cpumask_next((cpu), (mask)), \ + (cpu) < nr_cpu_ids;) +#define for_each_cpu_and(cpu, mask, and) \ + for ((cpu) = -1; \ + (cpu) = cpumask_next_and((cpu), (mask), (and)), \ + (cpu) < nr_cpu_ids;) +#endif /* SMP */ + +#define CPU_BITS_NONE \ +{ \ + [0 ... BITS_TO_LONGS(NR_CPUS)-1] = 0UL \ +} + +#define CPU_BITS_CPU0 \ +{ \ + [0] = 1UL \ +} + +/** + * cpumask_set_cpu - set a cpu in a cpumask + * @cpu: cpu number (< nr_cpu_ids) + * @dstp: the cpumask pointer + */ +static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) +{ + set_bit(cpumask_check(cpu), cpumask_bits(dstp)); +} + +/** + * cpumask_clear_cpu - clear a cpu in a cpumask + * @cpu: cpu number (< nr_cpu_ids) + * @dstp: the cpumask pointer + */ +static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp) +{ + clear_bit(cpumask_check(cpu), cpumask_bits(dstp)); +} + +/** + * cpumask_test_cpu - test for a cpu in a cpumask + * @cpu: cpu number (< nr_cpu_ids) + * @cpumask: the cpumask pointer + * + * No static inline type checking - see Subtlety (1) above. + */ +#define cpumask_test_cpu(cpu, cpumask) \ + test_bit(cpumask_check(cpu), (cpumask)->bits) + +/** + * cpumask_test_and_set_cpu - atomically test and set a cpu in a cpumask + * @cpu: cpu number (< nr_cpu_ids) + * @cpumask: the cpumask pointer + * + * test_and_set_bit wrapper for cpumasks. + */ +static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask) +{ + return test_and_set_bit(cpumask_check(cpu), cpumask_bits(cpumask)); +} + +/** + * cpumask_setall - set all cpus (< nr_cpu_ids) in a cpumask + * @dstp: the cpumask pointer + */ +static inline void cpumask_setall(struct cpumask *dstp) +{ + bitmap_fill(cpumask_bits(dstp), nr_cpumask_bits); +} + +/** + * cpumask_clear - clear all cpus (< nr_cpu_ids) in a cpumask + * @dstp: the cpumask pointer + */ +static inline void cpumask_clear(struct cpumask *dstp) +{ + bitmap_zero(cpumask_bits(dstp), nr_cpumask_bits); +} + +/** + * cpumask_and - *dstp = *src1p & *src2p + * @dstp: the cpumask result + * @src1p: the first input + * @src2p: the second input + */ +static inline void cpumask_and(struct cpumask *dstp, + const struct cpumask *src1p, + const struct cpumask *src2p) +{ + bitmap_and(cpumask_bits(dstp), cpumask_bits(src1p), + cpumask_bits(src2p), nr_cpumask_bits); +} + +/** + * cpumask_or - *dstp = *src1p | *src2p + * @dstp: the cpumask result + * @src1p: the first input + * @src2p: the second input + */ +static inline void cpumask_or(struct cpumask *dstp, const struct cpumask *src1p, + const struct cpumask *src2p) +{ + bitmap_or(cpumask_bits(dstp), cpumask_bits(src1p), + cpumask_bits(src2p), nr_cpumask_bits); +} + +/** + * cpumask_xor - *dstp = *src1p ^ *src2p + * @dstp: the cpumask result + * @src1p: the first input + * @src2p: the second input + */ +static inline void cpumask_xor(struct cpumask *dstp, + const struct cpumask *src1p, + const struct cpumask *src2p) +{ + bitmap_xor(cpumask_bits(dstp), cpumask_bits(src1p), + cpumask_bits(src2p), nr_cpumask_bits); +} + +/** + * cpumask_andnot - *dstp = *src1p & ~*src2p + * @dstp: the cpumask result + * @src1p: the first input + * @src2p: the second input + */ +static inline void cpumask_andnot(struct cpumask *dstp, + const struct cpumask *src1p, + const struct cpumask *src2p) +{ + bitmap_andnot(cpumask_bits(dstp), cpumask_bits(src1p), + cpumask_bits(src2p), nr_cpumask_bits); +} + +/** + * cpumask_complement - *dstp = ~*srcp + * @dstp: the cpumask result + * @srcp: the input to invert + */ +static inline void cpumask_complement(struct cpumask *dstp, + const struct cpumask *srcp) +{ + bitmap_complement(cpumask_bits(dstp), cpumask_bits(srcp), + nr_cpumask_bits); +} + +/** + * cpumask_equal - *src1p == *src2p + * @src1p: the first input + * @src2p: the second input + */ +static inline bool cpumask_equal(const struct cpumask *src1p, + const struct cpumask *src2p) +{ + return bitmap_equal(cpumask_bits(src1p), cpumask_bits(src2p), + nr_cpumask_bits); +} + +/** + * cpumask_intersects - (*src1p & *src2p) != 0 + * @src1p: the first input + * @src2p: the second input + */ +static inline bool cpumask_intersects(const struct cpumask *src1p, + const struct cpumask *src2p) +{ + return bitmap_intersects(cpumask_bits(src1p), cpumask_bits(src2p), + nr_cpumask_bits); +} + +/** + * cpumask_subset - (*src1p & ~*src2p) == 0 + * @src1p: the first input + * @src2p: the second input + */ +static inline int cpumask_subset(const struct cpumask *src1p, + const struct cpumask *src2p) +{ + return bitmap_subset(cpumask_bits(src1p), cpumask_bits(src2p), + nr_cpumask_bits); +} + +/** + * cpumask_empty - *srcp == 0 + * @srcp: the cpumask to that all cpus < nr_cpu_ids are clear. + */ +static inline bool cpumask_empty(const struct cpumask *srcp) +{ + return bitmap_empty(cpumask_bits(srcp), nr_cpumask_bits); +} + +/** + * cpumask_full - *srcp == 0xFFFFFFFF... + * @srcp: the cpumask to that all cpus < nr_cpu_ids are set. + */ +static inline bool cpumask_full(const struct cpumask *srcp) +{ + return bitmap_full(cpumask_bits(srcp), nr_cpumask_bits); +} + +/** + * cpumask_weight - Count of bits in *srcp + * @srcp: the cpumask to count bits (< nr_cpu_ids) in. + */ +static inline unsigned int cpumask_weight(const struct cpumask *srcp) +{ + return bitmap_weight(cpumask_bits(srcp), nr_cpumask_bits); +} + +/** + * cpumask_shift_right - *dstp = *srcp >> n + * @dstp: the cpumask result + * @srcp: the input to shift + * @n: the number of bits to shift by + */ +static inline void cpumask_shift_right(struct cpumask *dstp, + const struct cpumask *srcp, int n) +{ + bitmap_shift_right(cpumask_bits(dstp), cpumask_bits(srcp), n, + nr_cpumask_bits); +} + +/** + * cpumask_shift_left - *dstp = *srcp << n + * @dstp: the cpumask result + * @srcp: the input to shift + * @n: the number of bits to shift by + */ +static inline void cpumask_shift_left(struct cpumask *dstp, + const struct cpumask *srcp, int n) +{ + bitmap_shift_left(cpumask_bits(dstp), cpumask_bits(srcp), n, + nr_cpumask_bits); +} + +/** + * cpumask_copy - *dstp = *srcp + * @dstp: the result + * @srcp: the input cpumask + */ +static inline void cpumask_copy(struct cpumask *dstp, + const struct cpumask *srcp) +{ + bitmap_copy(cpumask_bits(dstp), cpumask_bits(srcp), nr_cpumask_bits); +} + +/** + * cpumask_any - pick a "random" cpu from *srcp + * @srcp: the input cpumask + * + * Returns >= nr_cpu_ids if no cpus set. + */ +#define cpumask_any(srcp) cpumask_first(srcp) + +/** + * cpumask_first_and - return the first cpu from *srcp1 & *srcp2 + * @src1p: the first input + * @src2p: the second input + * + * Returns >= nr_cpu_ids if no cpus set in both. See also cpumask_next_and(). + */ +#define cpumask_first_and(src1p, src2p) cpumask_next_and(-1, (src1p), (src2p)) + +/** + * cpumask_any_and - pick a "random" cpu from *mask1 & *mask2 + * @mask1: the first input cpumask + * @mask2: the second input cpumask + * + * Returns >= nr_cpu_ids if no cpus set. + */ +#define cpumask_any_and(mask1, mask2) cpumask_first_and((mask1), (mask2)) + +/** + * to_cpumask - convert an NR_CPUS bitmap to a struct cpumask * + * @bitmap: the bitmap + * + * There are a few places where cpumask_var_t isn't appropriate and + * static cpumasks must be used (eg. very early boot), yet we don't + * expose the definition of 'struct cpumask'. + * + * This does the conversion, and can be used as a constant initializer. + */ +#define to_cpumask(bitmap) \ + ((struct cpumask *)(1 ? (bitmap) \ + : (void *)sizeof(__check_is_bitmap(bitmap)))) + +static inline int __check_is_bitmap(const unsigned long *bitmap) +{ + return 1; +} + +/** + * cpumask_size - size to allocate for a 'struct cpumask' in bytes + * + * This will eventually be a runtime variable, depending on nr_cpu_ids. + */ +static inline size_t cpumask_size(void) +{ + /* FIXME: Once all cpumask assignments are eliminated, this + * can be nr_cpumask_bits */ + return BITS_TO_LONGS(NR_CPUS) * sizeof(long); +} + +/* + * cpumask_var_t: struct cpumask for stack usage. + * + * Oh, the wicked games we play! In order to make kernel coding a + * little more difficult, we typedef cpumask_var_t to an array or a + * pointer: doing &mask on an array is a noop, so it still works. + * + * ie. + * cpumask_var_t tmpmask; + * if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL)) + * return -ENOMEM; + * + * ... use 'tmpmask' like a normal struct cpumask * ... + * + * free_cpumask_var(tmpmask); + */ +#ifdef CONFIG_CPUMASK_OFFSTACK +typedef struct cpumask *cpumask_var_t; + +bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags); +void alloc_bootmem_cpumask_var(cpumask_var_t *mask); +void free_cpumask_var(cpumask_var_t mask); + +#else +typedef struct cpumask cpumask_var_t[1]; + +static inline bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) +{ + return true; +} + +static inline void alloc_bootmem_cpumask_var(cpumask_var_t *mask) +{ +} + +static inline void free_cpumask_var(cpumask_var_t mask) +{ +} +#endif /* CONFIG_CPUMASK_OFFSTACK */ + +/* The pointer versions of the maps, these will become the primary versions. */ +#define cpu_possible_mask ((const struct cpumask *)&cpu_possible_map) +#define cpu_online_mask ((const struct cpumask *)&cpu_online_map) +#define cpu_present_mask ((const struct cpumask *)&cpu_present_map) +#define cpu_active_mask ((const struct cpumask *)&cpu_active_map) + +/* It's common to want to use cpu_all_mask in struct member initializers, + * so it has to refer to an address rather than a pointer. */ +extern const DECLARE_BITMAP(cpu_all_bits, NR_CPUS); +#define cpu_all_mask to_cpumask(cpu_all_bits) + +/* First bits of cpu_bit_bitmap are in fact unset. */ +#define cpu_none_mask to_cpumask(cpu_bit_bitmap[0]) + +/* Wrappers for arch boot code to manipulate normally-constant masks */ +static inline void set_cpu_possible(unsigned int cpu, bool possible) +{ + if (possible) + cpumask_set_cpu(cpu, &cpu_possible_map); + else + cpumask_clear_cpu(cpu, &cpu_possible_map); +} + +static inline void set_cpu_present(unsigned int cpu, bool present) +{ + if (present) + cpumask_set_cpu(cpu, &cpu_present_map); + else + cpumask_clear_cpu(cpu, &cpu_present_map); +} + +static inline void set_cpu_online(unsigned int cpu, bool online) +{ + if (online) + cpumask_set_cpu(cpu, &cpu_online_map); + else + cpumask_clear_cpu(cpu, &cpu_online_map); +} + +static inline void set_cpu_active(unsigned int cpu, bool active) +{ + if (active) + cpumask_set_cpu(cpu, &cpu_active_map); + else + cpumask_clear_cpu(cpu, &cpu_active_map); +} + +static inline void init_cpu_present(const struct cpumask *src) +{ + cpumask_copy(&cpu_present_map, src); +} + +static inline void init_cpu_possible(const struct cpumask *src) +{ + cpumask_copy(&cpu_possible_map, src); +} + +static inline void init_cpu_online(const struct cpumask *src) +{ + cpumask_copy(&cpu_online_map, src); +} #endif /* __LINUX_CPUMASK_H */ diff --git a/include/linux/smp.h b/include/linux/smp.h index 2e4d58b26c06..3f9a60043a97 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -64,8 +64,17 @@ extern void smp_cpus_done(unsigned int max_cpus); * Call a function on all other processors */ int smp_call_function(void(*func)(void *info), void *info, int wait); +/* Deprecated: use smp_call_function_many() which uses a cpumask ptr. */ int smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info, int wait); + +static inline void smp_call_function_many(const struct cpumask *mask, + void (*func)(void *info), void *info, + int wait) +{ + smp_call_function_mask(*mask, func, info, wait); +} + int smp_call_function_single(int cpuid, void (*func) (void *info), void *info, int wait); void __smp_call_function_single(int cpuid, struct call_single_data *data); diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 89a5a1231ffb..b36291130f22 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -240,4 +240,12 @@ void cancel_rearming_delayed_work(struct delayed_work *work) cancel_delayed_work_sync(work); } +#ifndef CONFIG_SMP +static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) +{ + return fn(arg); +} +#else +long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg); +#endif /* CONFIG_SMP */ #endif diff --git a/kernel/cpu.c b/kernel/cpu.c index 86d49045daed..5a732c5ef08b 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -499,3 +499,6 @@ const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { #endif }; EXPORT_SYMBOL_GPL(cpu_bit_bitmap); + +const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; +EXPORT_SYMBOL(cpu_all_bits); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index f928f2a87b9b..d4dc69ddebd7 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -970,6 +970,51 @@ undo: return ret; } +#ifdef CONFIG_SMP +struct work_for_cpu { + struct work_struct work; + long (*fn)(void *); + void *arg; + long ret; +}; + +static void do_work_for_cpu(struct work_struct *w) +{ + struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work); + + wfc->ret = wfc->fn(wfc->arg); +} + +/** + * work_on_cpu - run a function in user context on a particular cpu + * @cpu: the cpu to run on + * @fn: the function to run + * @arg: the function arg + * + * This will return -EINVAL in the cpu is not online, or the return value + * of @fn otherwise. + */ +long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) +{ + struct work_for_cpu wfc; + + INIT_WORK(&wfc.work, do_work_for_cpu); + wfc.fn = fn; + wfc.arg = arg; + get_online_cpus(); + if (unlikely(!cpu_online(cpu))) + wfc.ret = -EINVAL; + else { + schedule_work_on(cpu, &wfc.work); + flush_work(&wfc.work); + } + put_online_cpus(); + + return wfc.ret; +} +EXPORT_SYMBOL_GPL(work_on_cpu); +#endif /* CONFIG_SMP */ + void __init init_workqueues(void) { cpu_populated_map = cpu_online_map; diff --git a/lib/cpumask.c b/lib/cpumask.c index 5f97dc25ef9c..5ceb4211c834 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -2,6 +2,7 @@ #include #include #include +#include int __first_cpu(const cpumask_t *srcp) { @@ -35,3 +36,75 @@ int __any_online_cpu(const cpumask_t *mask) return cpu; } EXPORT_SYMBOL(__any_online_cpu); + +/** + * cpumask_next_and - get the next cpu in *src1p & *src2p + * @n: the cpu prior to the place to search (ie. return will be > @n) + * @src1p: the first cpumask pointer + * @src2p: the second cpumask pointer + * + * Returns >= nr_cpu_ids if no further cpus set in both. + */ +int cpumask_next_and(int n, const struct cpumask *src1p, + const struct cpumask *src2p) +{ + while ((n = cpumask_next(n, src1p)) < nr_cpu_ids) + if (cpumask_test_cpu(n, src2p)) + break; + return n; +} +EXPORT_SYMBOL(cpumask_next_and); + +/** + * cpumask_any_but - return a "random" in a cpumask, but not this one. + * @mask: the cpumask to search + * @cpu: the cpu to ignore. + * + * Often used to find any cpu but smp_processor_id() in a mask. + * Returns >= nr_cpu_ids if no cpus set. + */ +int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) +{ + unsigned int i; + + for_each_cpu(i, mask) + if (i != cpu) + break; + return i; +} + +/* These are not inline because of header tangles. */ +#ifdef CONFIG_CPUMASK_OFFSTACK +bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) +{ + if (likely(slab_is_available())) + *mask = kmalloc(cpumask_size(), flags); + else { +#ifdef CONFIG_DEBUG_PER_CPU_MAPS + printk(KERN_ERR + "=> alloc_cpumask_var: kmalloc not available!\n"); + dump_stack(); +#endif + *mask = NULL; + } +#ifdef CONFIG_DEBUG_PER_CPU_MAPS + if (!*mask) { + printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); + dump_stack(); + } +#endif + return *mask != NULL; +} +EXPORT_SYMBOL(alloc_cpumask_var); + +void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) +{ + *mask = alloc_bootmem(cpumask_size()); +} + +void free_cpumask_var(cpumask_var_t mask) +{ + kfree(mask); +} +EXPORT_SYMBOL(free_cpumask_var); +#endif -- cgit v1.2.3 From 24eb089950ce44603b30a3145a2c8520e2b55bb1 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 6 Nov 2008 12:53:32 -0800 Subject: cgroups: fix invalid cgrp->dentry before cgroup has been completely removed This fixes an oops when reading /proc/sched_debug. A cgroup won't be removed completely until finishing cgroup_diput(), so we shouldn't invalidate cgrp->dentry in cgroup_rmdir(). Otherwise, when a group is being removed while cgroup_path() gets called, we may trigger NULL dereference BUG. The bug can be reproduced: # cat test.sh #!/bin/sh mount -t cgroup -o cpu xxx /mnt for (( ; ; )) { mkdir /mnt/sub rmdir /mnt/sub } # ./test.sh & # cat /proc/sched_debug BUG: unable to handle kernel NULL pointer dereference at 00000038 IP: [] cgroup_path+0x39/0x90 ... Call Trace: [] ? print_cfs_rq+0x6e/0x75d [] ? sched_debug_show+0x72d/0xc1e ... Signed-off-by: Li Zefan Acked-by: Paul Menage Cc: Peter Zijlstra Cc: Ingo Molnar Cc: [2.6.26.x, 2.6.27.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cgroup.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 35eebd5510c2..358e77564e6f 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2497,7 +2497,6 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) list_del(&cgrp->sibling); spin_lock(&cgrp->dentry->d_lock); d = dget(cgrp->dentry); - cgrp->dentry = NULL; spin_unlock(&d->d_lock); cgroup_d_remove_dir(d); -- cgit v1.2.3 From f29c9b1ccb52904ee442a933cf3dee628f9f4e62 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 6 Nov 2008 09:45:16 +0800 Subject: sched: fix a bug in sched domain degenerate Impact: re-add incorrectly eliminated sched domain layers (1) on i386 with SCHED_SMT and SCHED_MC enabled # mount -t cgroup -o cpuset xxx /mnt # echo 0 > /mnt/cpuset.sched_load_balance # mkdir /mnt/0 # echo 0 > /mnt/0/cpuset.cpus # dmesg CPU0 attaching sched-domain: domain 0: span 0 level CPU groups: 0 (2) on i386 with SCHED_MC enabled but SCHED_SMT disabled # same with (1) # dmesg CPU0 attaching NULL sched-domain. The bug is that some sched domains may be skipped unintentionally when degenerating (optimizing) sched domains. Signed-off-by: Li Zefan Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 82cc839c9210..4c7e2bcdfa89 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6877,15 +6877,17 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) struct sched_domain *tmp; /* Remove the sched domains which do not contribute to scheduling. */ - for (tmp = sd; tmp; tmp = tmp->parent) { + for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; if (!parent) break; + if (sd_parent_degenerate(tmp, parent)) { tmp->parent = parent->parent; if (parent->parent) parent->parent->child = tmp; - } + } else + tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { -- cgit v1.2.3 From ca3273f9646694e0419cfb9d6c12deb1c9aff27c Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 7 Nov 2008 14:47:21 +0800 Subject: sched: fix memory leak in a failure path Impact: fix rare memory leak in the sched-domains manual reconfiguration code In the failure path, rd is not attached to a sched domain, so it causes a leak. Signed-off-by: Li Zefan Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 4c7e2bcdfa89..57c933ffbee1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7676,6 +7676,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map, error: free_sched_groups(cpu_map, tmpmask); SCHED_CPUMASK_FREE((void *)allmasks); + kfree(rd); return -ENOMEM; #endif } -- cgit v1.2.3 From 5ac5c4d604bf894ef672a7971d03fefdc7ea7e49 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 10 Nov 2008 10:46:32 +0100 Subject: sched: clean up debug info Impact: clean up and fix debug info printout While looking over the sched_debug code I noticed that we printed the rq schedstats for every cfs_rq, ammend this. Also change nr_spead_over into an int, and fix a little buglet in min_vruntime printing. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- kernel/sched_debug.c | 41 +++++++++++++++++++++-------------------- 2 files changed, 22 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 57c933ffbee1..f3149244e324 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -399,7 +399,7 @@ struct cfs_rq { */ struct sched_entity *curr, *next, *last; - unsigned long nr_spread_over; + unsigned int nr_spread_over; #ifdef CONFIG_FAIR_GROUP_SCHED struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 5ae17762ec32..48ecc51e7701 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -144,7 +144,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) last = __pick_last_entity(cfs_rq); if (last) max_vruntime = last->vruntime; - min_vruntime = rq->cfs.min_vruntime; + min_vruntime = cfs_rq->min_vruntime; rq0_min_vruntime = per_cpu(runqueues, 0).cfs.min_vruntime; spin_unlock_irqrestore(&rq->lock, flags); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "MIN_vruntime", @@ -161,26 +161,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) SPLIT_NS(spread0)); SEQ_printf(m, " .%-30s: %ld\n", "nr_running", cfs_rq->nr_running); SEQ_printf(m, " .%-30s: %ld\n", "load", cfs_rq->load.weight); -#ifdef CONFIG_SCHEDSTATS -#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n); - - P(yld_exp_empty); - P(yld_act_empty); - P(yld_both_empty); - P(yld_count); - P(sched_switch); - P(sched_count); - P(sched_goidle); - - P(ttwu_count); - P(ttwu_local); - - P(bkl_count); - -#undef P -#endif - SEQ_printf(m, " .%-30s: %ld\n", "nr_spread_over", + SEQ_printf(m, " .%-30s: %d\n", "nr_spread_over", cfs_rq->nr_spread_over); #ifdef CONFIG_FAIR_GROUP_SCHED #ifdef CONFIG_SMP @@ -260,6 +242,25 @@ static void print_cpu(struct seq_file *m, int cpu) #undef P #undef PN +#ifdef CONFIG_SCHEDSTATS +#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n); + + P(yld_exp_empty); + P(yld_act_empty); + P(yld_both_empty); + P(yld_count); + + P(sched_switch); + P(sched_count); + P(sched_goidle); + + P(ttwu_count); + P(ttwu_local); + + P(bkl_count); + +#undef P +#endif print_cfs_stats(m, cpu); print_rt_stats(m, cpu); -- cgit v1.2.3 From ee5f80a993539490a07477ff2526bf62c503fbb4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 7 Nov 2008 11:06:00 +0100 Subject: irq: call __irq_enter() before calling the tick_idle_check Impact: avoid spurious ksoftirqd wakeups The tick idle check which is called from irq_enter() was run before the call to __irq_enter() which did not set the in_interrupt() bits in preempt_count. That way the raise of a softirq woke up softirqd for nothing as the softirq was handled on return from interrupt. Call __irq_enter() before calling into the tick idle check code. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/softirq.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/softirq.c b/kernel/softirq.c index 7110daeb9a90..e7c69a720d69 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -269,10 +269,11 @@ void irq_enter(void) { int cpu = smp_processor_id(); - if (idle_cpu(cpu) && !in_interrupt()) + if (idle_cpu(cpu) && !in_interrupt()) { + __irq_enter(); tick_check_idle(cpu); - - __irq_enter(); + } else + __irq_enter(); } #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED -- cgit v1.2.3 From ae99286b4f1be7788f2d6947c66a91dbd6351eec Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 10 Nov 2008 13:20:23 +0100 Subject: nohz: disable tick_nohz_kick_tick() for now Impact: nohz powersavings and wakeup regression commit fb02fbc14d17837b4b7b02dbb36142c16a7bf208 (NOHZ: restart tick device from irq_enter()) causes a serious wakeup regression. While the patch is correct it does not take into account that spurious wakeups happen on x86. A fix for this issue is available, but we just revert to the .27 behaviour and let long running softirqs screw themself. Disable it for now. Signed-off-by: Thomas Gleixner --- kernel/time/tick-sched.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 5bbb1044f847..342fc9ccab46 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -568,6 +568,9 @@ static void tick_nohz_switch_to_nohz(void) */ static void tick_nohz_kick_tick(int cpu) { +#if 0 + /* Switch back to 2.6.27 behaviour */ + struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); ktime_t delta, now; @@ -584,6 +587,7 @@ static void tick_nohz_kick_tick(int cpu) return; tick_nohz_restart(ts, now); +#endif } #else -- cgit v1.2.3 From bf5e6519b85b3853f2d0bb4f17a4e2eaeffeb574 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 10 Nov 2008 21:46:00 -0500 Subject: ftrace: disable tracing on resize Impact: fix for bug on resize This patch addresses the bug found here: http://bugzilla.kernel.org/show_bug.cgi?id=11996 When ftrace converted to the new unified trace buffer, the resizing of the buffer was not protected as much as it was originally. If tracing is performed while the resize occurs, then the buffer can be corrupted. This patch disables all ftrace buffer modifications before a resize takes place. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9f3b478f9171..abfa8103d046 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2676,7 +2676,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, { unsigned long val; char buf[64]; - int ret; + int ret, cpu; struct trace_array *tr = filp->private_data; if (cnt >= sizeof(buf)) @@ -2704,6 +2704,14 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, goto out; } + /* disable all cpu buffers */ + for_each_tracing_cpu(cpu) { + if (global_trace.data[cpu]) + atomic_inc(&global_trace.data[cpu]->disabled); + if (max_tr.data[cpu]) + atomic_inc(&max_tr.data[cpu]->disabled); + } + if (val != global_trace.entries) { ret = ring_buffer_resize(global_trace.buffer, val); if (ret < 0) { @@ -2735,6 +2743,13 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, if (tracing_disabled) cnt = -ENOMEM; out: + for_each_tracing_cpu(cpu) { + if (global_trace.data[cpu]) + atomic_dec(&global_trace.data[cpu]->disabled); + if (max_tr.data[cpu]) + atomic_dec(&max_tr.data[cpu]->disabled); + } + max_tr.entries = global_trace.entries; mutex_unlock(&trace_types_lock); -- cgit v1.2.3 From 4143c5cb36331155a1823af8b3a8c761a59fed71 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 10 Nov 2008 21:46:01 -0500 Subject: ring-buffer: prevent infinite looping on time stamping Impact: removal of unnecessary looping The lockless part of the ring buffer allows for reentry into the code from interrupts. A timestamp is taken, a test is preformed and if it detects that an interrupt occurred that did tracing, it tries again. The problem arises if the timestamp code itself causes a trace. The detection will detect this and loop again. The difference between this and an interrupt doing tracing, is that this will fail every time, and cause an infinite loop. Currently, we test if the loop happens 1000 times, and if so, it will produce a warning and disable the ring buffer. The problem with this approach is that it makes it difficult to perform some types of tracing (tracing the timestamp code itself). Each trace entry has a delta timestamp from the previous entry. If a trace entry is reserved but and interrupt occurs and traces before the previous entry is commited, the delta timestamp for that entry will be zero. This actually makes sense in terms of tracing, because the interrupt entry happened before the preempted entry was commited, so one may consider the two happening at the same time. The order is still preserved in the buffer. With this idea, instead of trying to get a new timestamp if an interrupt made it in between the timestamp and the test, the entry could simply make the delta zero and continue. This will prevent interrupts or tracers in the timer code from causing the above loop. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 3f3380638646..2f76193c3489 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1060,7 +1060,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer, /* Did the write stamp get updated already? */ if (unlikely(ts < cpu_buffer->write_stamp)) - goto again; + delta = 0; if (test_time_stamp(delta)) { -- cgit v1.2.3 From ad474caca3e2a0550b7ce0706527ad5ab389a4d4 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 10 Nov 2008 15:39:30 +0100 Subject: fix for account_group_exec_runtime(), make sure ->signal can't be freed under rq->lock Impact: fix hang/crash on ia64 under high load This is ugly, but the simplest patch by far. Unlike other similar routines, account_group_exec_runtime() could be called "implicitly" from within scheduler after exit_notify(). This means we can race with the parent doing release_task(), we can't just check ->signal != NULL. Change __exit_signal() to do spin_unlock_wait(&task_rq(tsk)->lock) before __cleanup_signal() to make sure ->signal can't be freed under task_rq(tsk)->lock. Note that task_rq_unlock_wait() doesn't care about the case when tsk changes cpu/rq under us, this should be OK. Thanks to Ingo who nacked my previous buggy patch. Signed-off-by: Oleg Nesterov Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar Reported-by: Doug Chapman --- include/linux/sched.h | 1 + kernel/exit.c | 5 +++++ kernel/sched.c | 8 ++++++++ 3 files changed, 14 insertions(+) (limited to 'kernel') diff --git a/include/linux/sched.h b/include/linux/sched.h index 295b7c756ca6..644ffbda17ca 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -247,6 +247,7 @@ extern void init_idle(struct task_struct *idle, int cpu); extern void init_idle_bootup_task(struct task_struct *idle); extern int runqueue_is_locked(void); +extern void task_rq_unlock_wait(struct task_struct *p); extern cpumask_t nohz_cpu_mask; #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ) diff --git a/kernel/exit.c b/kernel/exit.c index 80137a5d9467..ae2b92be5fae 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -141,6 +141,11 @@ static void __exit_signal(struct task_struct *tsk) if (sig) { flush_sigqueue(&sig->shared_pending); taskstats_tgid_free(sig); + /* + * Make sure ->signal can't go away under rq->lock, + * see account_group_exec_runtime(). + */ + task_rq_unlock_wait(tsk); __cleanup_signal(sig); } } diff --git a/kernel/sched.c b/kernel/sched.c index f3149244e324..50a21f964679 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -969,6 +969,14 @@ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) } } +void task_rq_unlock_wait(struct task_struct *p) +{ + struct rq *rq = task_rq(p); + + smp_mb(); /* spin-unlock-wait is not a full memory barrier */ + spin_unlock_wait(&rq->lock); +} + static void __task_rq_unlock(struct rq *rq) __releases(rq->lock) { -- cgit v1.2.3 From 5d5254f0d3b9bebc47d97e357374c0ad0c291a7d Mon Sep 17 00:00:00 2001 From: Gautham R Shenoy Date: Sat, 25 Oct 2008 10:22:38 +0530 Subject: timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq context Impact: fix incorrect locking triggered during hotplug-intense stress-tests While migrating the the CB_IRQSAFE_UNLOCKED timers during a cpu-offline, we queue them on the cb_pending list, so that they won't go stale. Thus, when the callbacks of the timers run from the softirq context, they could run into potential deadlocks, since these callbacks assume that they're running with irq's disabled, thereby annoying lockdep! Fix this by emulating hardirq context while running these callbacks from the hrtimer softirq. ================================= [ INFO: inconsistent lock state ] 2.6.27 #2 -------------------------------- inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes: (&rq->lock){++..}, at: [] sched_rt_period_timer+0x9e/0x1fc {in-hardirq-W} state was registered at: [] __lock_acquire+0x549/0x121e [] native_sched_clock+0x88/0x99 [] clocksource_get_next+0x39/0x3f [] update_wall_time+0x616/0x7df [] lock_acquire+0x5a/0x74 [] scheduler_tick+0x3a/0x18d [] _spin_lock+0x1c/0x45 [] scheduler_tick+0x3a/0x18d [] scheduler_tick+0x3a/0x18d [] update_process_times+0x3a/0x44 [] tick_periodic+0x63/0x6d [] tick_handle_periodic+0x14/0x5e [] timer_interrupt+0x44/0x4a [] handle_IRQ_event+0x13/0x3d [] handle_level_irq+0x79/0xbd [] do_IRQ+0x69/0x7d [] common_interrupt+0x28/0x30 [] aac_probe_one+0x1a3/0x3f3 [] _spin_unlock_irqrestore+0x36/0x39 [] setup_irq+0x1be/0x1f9 [] start_kernel+0x259/0x2c5 [] 0xffffffff irq event stamp: 50102 hardirqs last enabled at (50102): [] _spin_unlock_irq+0x20/0x23 hardirqs last disabled at (50101): [] _spin_lock_irq+0xa/0x4b softirqs last enabled at (50088): [] do_softirq+0x37/0x4d softirqs last disabled at (50099): [] do_softirq+0x37/0x4d other info that might help us debug this: no locks held by ksoftirqd/0/4. stack backtrace: Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27 #2 [] print_usage_bug+0x13e/0x147 [] mark_lock+0x493/0x797 [] __lock_acquire+0x5be/0x121e [] lock_acquire+0x5a/0x74 [] sched_rt_period_timer+0x9e/0x1fc [] _spin_lock+0x1c/0x45 [] sched_rt_period_timer+0x9e/0x1fc [] sched_rt_period_timer+0x9e/0x1fc [] finish_task_switch+0x41/0xbd [] native_sched_clock+0x88/0x99 [] sched_rt_period_timer+0x0/0x1fc [] run_hrtimer_pending+0x54/0xe5 [] sched_rt_period_timer+0x0/0x1fc [] __do_softirq+0x7b/0xef [] do_softirq+0x37/0x4d [] ksoftirqd+0x56/0xc5 [] ksoftirqd+0x0/0xc5 [] kthread+0x38/0x5d [] kthread+0x0/0x5d [] kernel_thread_helper+0x7/0x10 ======================= Signed-off-by: Gautham R Shenoy Acked-by: Peter Zijlstra Acked-by: "Paul E. McKenney" Signed-off-by: Ingo Molnar --- kernel/hrtimer.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 2b465dfde426..95d3949f2ae5 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1209,6 +1209,7 @@ static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base) enum hrtimer_restart (*fn)(struct hrtimer *); struct hrtimer *timer; int restart; + int emulate_hardirq_ctx = 0; timer = list_entry(cpu_base->cb_pending.next, struct hrtimer, cb_entry); @@ -1217,10 +1218,24 @@ static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base) timer_stats_account_hrtimer(timer); fn = timer->function; + /* + * A timer might have been added to the cb_pending list + * when it was migrated during a cpu-offline operation. + * Emulate hardirq context for such timers. + */ + if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU || + timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED) + emulate_hardirq_ctx = 1; + __remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0); spin_unlock_irq(&cpu_base->lock); - restart = fn(timer); + if (unlikely(emulate_hardirq_ctx)) { + local_irq_disable(); + restart = fn(timer); + local_irq_enable(); + } else + restart = fn(timer); spin_lock_irq(&cpu_base->lock); -- cgit v1.2.3 From 2002c69595a092518107f7e3c1294c9710bc92ae Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 11 Nov 2008 11:52:33 +0100 Subject: sched: release buddies on yield Clear buddies on yield, so that the buddy rules don't schedule them despite them being placed right-most. This fixed a performance regression with yield-happy binary JVMs. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar Tested-by: Lin Ming --- kernel/sched_fair.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 51aa3e102acb..98345e45b059 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -716,6 +716,15 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) __enqueue_entity(cfs_rq, se); } +static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + if (cfs_rq->last == se) + cfs_rq->last = NULL; + + if (cfs_rq->next == se) + cfs_rq->next = NULL; +} + static void dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) { @@ -738,11 +747,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) #endif } - if (cfs_rq->last == se) - cfs_rq->last = NULL; - - if (cfs_rq->next == se) - cfs_rq->next = NULL; + clear_buddies(cfs_rq, se); if (se != cfs_rq->curr) __dequeue_entity(cfs_rq, se); @@ -977,6 +982,8 @@ static void yield_task_fair(struct rq *rq) if (unlikely(cfs_rq->nr_running == 1)) return; + clear_buddies(cfs_rq, se); + if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) { update_rq_clock(rq); /* -- cgit v1.2.3 From 621a0d5207c18012cb39932f2d9830a11a6cb03d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 12 Nov 2008 09:36:35 +0100 Subject: hrtimer: clean up unused callback modes Impact: cleanup git grep HRTIMER_CB_IRQSAFE revealed half the callback modes are actually unused. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- include/linux/hrtimer.h | 5 ----- kernel/hrtimer.c | 9 --------- 2 files changed, 14 deletions(-) (limited to 'kernel') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 07e510a3b00a..3eba43878dcb 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -46,9 +46,6 @@ enum hrtimer_restart { * hrtimer callback modes: * * HRTIMER_CB_SOFTIRQ: Callback must run in softirq context - * HRTIMER_CB_IRQSAFE: Callback may run in hardirq context - * HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and - * does not restart the timer * HRTIMER_CB_IRQSAFE_PERCPU: Callback must run in hardirq context * Special mode for tick emulation and * scheduler timer. Such timers are per @@ -61,8 +58,6 @@ enum hrtimer_restart { */ enum hrtimer_cb_mode { HRTIMER_CB_SOFTIRQ, - HRTIMER_CB_IRQSAFE, - HRTIMER_CB_IRQSAFE_NO_RESTART, HRTIMER_CB_IRQSAFE_PERCPU, HRTIMER_CB_IRQSAFE_UNLOCKED, }; diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 95d3949f2ae5..47e63349d1b2 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -664,14 +664,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, /* Timer is expired, act upon the callback mode */ switch(timer->cb_mode) { - case HRTIMER_CB_IRQSAFE_NO_RESTART: - debug_hrtimer_deactivate(timer); - /* - * We can call the callback from here. No restart - * happens, so no danger of recursion - */ - BUG_ON(timer->function(timer) != HRTIMER_NORESTART); - return 1; case HRTIMER_CB_IRQSAFE_PERCPU: case HRTIMER_CB_IRQSAFE_UNLOCKED: /* @@ -683,7 +675,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, */ debug_hrtimer_deactivate(timer); return 1; - case HRTIMER_CB_IRQSAFE: case HRTIMER_CB_SOFTIRQ: /* * Move everything else into the softirq pending list ! -- cgit v1.2.3 From a2d477778e82a60a0b7114cefdb70aa43af28782 Mon Sep 17 00:00:00 2001 From: Balbir Singh Date: Wed, 12 Nov 2008 16:19:00 +0530 Subject: sched: fix stale value in average load per task Impact: fix load balancer load average calculation accuracy cpu_avg_load_per_task() returns a stale value when nr_running is 0. It returns an older stale (caculated when nr_running was non zero) value. This patch returns and sets rq->avg_load_per_task to zero when nr_running is 0. Compile and boot tested on a x86_64 box. Signed-off-by: Balbir Singh Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 50a21f964679..3bafbe350f4f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1456,6 +1456,8 @@ static unsigned long cpu_avg_load_per_task(int cpu) if (rq->nr_running) rq->avg_load_per_task = rq->load.weight / rq->nr_running; + else + rq->avg_load_per_task = 0; return rq->avg_load_per_task; } -- cgit v1.2.3 From 5cbd54ef470d880fc37fbe4b21eb514806d51e0d Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 12 Nov 2008 20:05:50 +0100 Subject: sched: fix init_idle()'s use of sched_clock() Maciej Rutecki reported: > I have this bug during suspend to disk: > > [ 188.592151] Enabling non-boot CPUs ... > [ 188.592151] SMP alternatives: switching to SMP code > [ 188.666058] BUG: using smp_processor_id() in preemptible > [00000000] > code: suspend_to_disk/2934 > [ 188.666064] caller is native_sched_clock+0x2b/0x80 Which, as noted by Linus, was caused by me, via: 7cbaef9c "sched: optimize sched_clock() a bit" Move the rq locking a bit earlier in the initialization sequence, that will make the sched_clock() call in init_idle() non-preemptible. Reported-by: Maciej Rutecki Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 3bafbe350f4f..c94baf2969e7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5870,6 +5870,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) struct rq *rq = cpu_rq(cpu); unsigned long flags; + spin_lock_irqsave(&rq->lock, flags); + __sched_fork(idle); idle->se.exec_start = sched_clock(); @@ -5877,7 +5879,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) idle->cpus_allowed = cpumask_of_cpu(cpu); __set_task_cpu(idle, cpu); - spin_lock_irqsave(&rq->lock, flags); rq->curr = rq->idle = idle; #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) idle->oncpu = 1; -- cgit v1.2.3 From 687446760bd008df96655cb8c5900f8e48a7118c Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 12 Nov 2008 13:26:49 -0800 Subject: freezer_cg: remove task_lock from freezer_fork() In theory the task can be moved to another cgroup and the freezer will be freed right after task_lock is dropped, so the lock results in zero protection. But in the case of freezer_fork() no lock is needed, since the task is not in tasklist yet so it won't be moved to another cgroup, so task->cgroups won't be changed or invalidated. Signed-off-by: Li Zefan Cc: Matt Helsley Cc: Cedric Le Goater Cc: "Serge E. Hallyn" Cc: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cgroup_freezer.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c index 7fa476f01d05..660590710409 100644 --- a/kernel/cgroup_freezer.c +++ b/kernel/cgroup_freezer.c @@ -184,9 +184,13 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task) { struct freezer *freezer; - task_lock(task); + /* + * No lock is needed, since the task isn't on tasklist yet, + * so it can't be moved to another cgroup, which means the + * freezer won't be removed and will be valid during this + * function call. + */ freezer = task_freezer(task); - task_unlock(task); spin_lock_irq(&freezer->lock); BUG_ON(freezer->state == CGROUP_FROZEN); -- cgit v1.2.3 From 3b1b3f6e57064aa8f91c290fe51cda4c74642902 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 12 Nov 2008 13:26:50 -0800 Subject: freezer_cg: disable writing freezer.state of root cgroup With this change, control file 'freezer.state' doesn't exist in root cgroup, making root cgroup unfreezable. I think it's reasonable to disallow freeze tasks in the root cgroup. And then we can avoid fork overhead when freezer subsystem is compiled but not used. Also make writing invalid value to freezer.state returns EINVAL rather than EIO. This is more consistent with other cgroup subsystem. Signed-off-by: Li Zefan Acked-by: Paul Menage Cc: Cedric Le Goater Cc: Paul Menage Cc: Matt Helsley Cc: "Serge E. Hallyn" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cgroups/freezer-subsystem.txt | 21 ++++++++++++--------- kernel/cgroup_freezer.c | 11 ++++++++++- 2 files changed, 22 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/Documentation/cgroups/freezer-subsystem.txt b/Documentation/cgroups/freezer-subsystem.txt index c50ab58b72eb..41f37fea1276 100644 --- a/Documentation/cgroups/freezer-subsystem.txt +++ b/Documentation/cgroups/freezer-subsystem.txt @@ -1,4 +1,4 @@ - The cgroup freezer is useful to batch job management system which start +The cgroup freezer is useful to batch job management system which start and stop sets of tasks in order to schedule the resources of a machine according to the desires of a system administrator. This sort of program is often used on HPC clusters to schedule access to the cluster as a @@ -6,7 +6,7 @@ whole. The cgroup freezer uses cgroups to describe the set of tasks to be started/stopped by the batch job management system. It also provides a means to start and stop the tasks composing the job. - The cgroup freezer will also be useful for checkpointing running groups +The cgroup freezer will also be useful for checkpointing running groups of tasks. The freezer allows the checkpoint code to obtain a consistent image of the tasks by attempting to force the tasks in a cgroup into a quiescent state. Once the tasks are quiescent another task can @@ -16,7 +16,7 @@ recoverable error occur. This also allows the checkpointed tasks to be migrated between nodes in a cluster by copying the gathered information to another node and restarting the tasks there. - Sequences of SIGSTOP and SIGCONT are not always sufficient for stopping +Sequences of SIGSTOP and SIGCONT are not always sufficient for stopping and resuming tasks in userspace. Both of these signals are observable from within the tasks we wish to freeze. While SIGSTOP cannot be caught, blocked, or ignored it can be seen by waiting or ptracing parent tasks. @@ -37,26 +37,29 @@ demonstrate this problem using nested bash shells: - This happens because bash can observe both signals and choose how it +This happens because bash can observe both signals and choose how it responds to them. - Another example of a program which catches and responds to these +Another example of a program which catches and responds to these signals is gdb. In fact any program designed to use ptrace is likely to have a problem with this method of stopping and resuming tasks. - In contrast, the cgroup freezer uses the kernel freezer code to +In contrast, the cgroup freezer uses the kernel freezer code to prevent the freeze/unfreeze cycle from becoming visible to the tasks being frozen. This allows the bash example above and gdb to run as expected. - The freezer subsystem in the container filesystem defines a file named +The freezer subsystem in the container filesystem defines a file named freezer.state. Writing "FROZEN" to the state file will freeze all tasks in the cgroup. Subsequently writing "THAWED" will unfreeze the tasks in the cgroup. Reading will return the current state. +Note freezer.state doesn't exist in root cgroup, which means root cgroup +is non-freezable. + * Examples of usage : - # mkdir /containers/freezer + # mkdir /containers # mount -t cgroup -ofreezer freezer /containers # mkdir /containers/0 # echo $some_pid > /containers/0/tasks @@ -94,6 +97,6 @@ things happens: the freezer.state file 2) Userspace retries the freezing operation by writing "FROZEN" to the freezer.state file (writing "FREEZING" is not legal - and returns EIO) + and returns EINVAL) 3) The tasks that blocked the cgroup from entering the "FROZEN" state disappear from the cgroup's set of tasks. diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c index 660590710409..fb249e2bcada 100644 --- a/kernel/cgroup_freezer.c +++ b/kernel/cgroup_freezer.c @@ -192,6 +192,13 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task) */ freezer = task_freezer(task); + /* + * The root cgroup is non-freezable, so we can skip the + * following check. + */ + if (!freezer->css.cgroup->parent) + return; + spin_lock_irq(&freezer->lock); BUG_ON(freezer->state == CGROUP_FROZEN); @@ -335,7 +342,7 @@ static int freezer_write(struct cgroup *cgroup, else if (strcmp(buffer, freezer_state_strs[CGROUP_FROZEN]) == 0) goal_state = CGROUP_FROZEN; else - return -EIO; + return -EINVAL; if (!cgroup_lock_live_group(cgroup)) return -ENODEV; @@ -354,6 +361,8 @@ static struct cftype files[] = { static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup) { + if (!cgroup->parent) + return 0; return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files)); } -- cgit v1.2.3 From a189d0350f387786b1fb5a5d19e3a5ab0bc0cceb Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 12 Nov 2008 13:26:51 -0800 Subject: kprobes: disable preempt for module_text_address() and kernel_text_address() __register_kprobe() can be preempted after checking probing address but before module_text_address() or try_module_get(), and in this interval the module can be unloaded. In that case, try_module_get(probed_mod) will access to invalid address, or kprobe will probe invalid address. This patch uses preempt_disable() to protect it and uses __module_text_address() and __kernel_text_address(). Signed-off-by: Lai Jiangshan Signed-off-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Hiroshi Shimamoto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 8b57a2597f21..f83c5e42fb07 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -613,30 +613,37 @@ static int __kprobes __register_kprobe(struct kprobe *p, return -EINVAL; p->addr = addr; - if (!kernel_text_address((unsigned long) p->addr) || - in_kprobes_functions((unsigned long) p->addr)) + preempt_disable(); + if (!__kernel_text_address((unsigned long) p->addr) || + in_kprobes_functions((unsigned long) p->addr)) { + preempt_enable(); return -EINVAL; + } p->mod_refcounted = 0; /* * Check if are we probing a module. */ - probed_mod = module_text_address((unsigned long) p->addr); + probed_mod = __module_text_address((unsigned long) p->addr); if (probed_mod) { - struct module *calling_mod = module_text_address(called_from); + struct module *calling_mod; + calling_mod = __module_text_address(called_from); /* * We must allow modules to probe themself and in this case * avoid incrementing the module refcount, so as to allow * unloading of self probing modules. */ if (calling_mod && calling_mod != probed_mod) { - if (unlikely(!try_module_get(probed_mod))) + if (unlikely(!try_module_get(probed_mod))) { + preempt_enable(); return -EINVAL; + } p->mod_refcounted = 1; } else probed_mod = NULL; } + preempt_enable(); p->nmissed = 0; INIT_LIST_HEAD(&p->list); @@ -718,6 +725,10 @@ static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) struct kprobe *old_p; if (p->mod_refcounted) { + /* + * Since we've already incremented refcount, + * we don't need to disable preemption. + */ mod = module_text_address((unsigned long)p->addr); if (mod) module_put(mod); -- cgit v1.2.3 From 7e036d040a28bf95255d7eb9faf0ffbba3677e99 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Wed, 12 Nov 2008 13:26:57 -0800 Subject: kernel/kprobes.c: don't pad kretprobe_table_locks[] on uniprocessor builds We only need the cacheline padding on SMP kernels. Saves 6k: text data bss dec hex filename 5713 388 8840 14941 3a5d kernel/kprobes.o 5713 388 2632 8733 221d kernel/kprobes.o Acked-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index f83c5e42fb07..9f8a3f25259a 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -72,7 +72,7 @@ static bool kprobe_enabled; DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; static struct { - spinlock_t lock ____cacheline_aligned; + spinlock_t lock ____cacheline_aligned_in_smp; } kretprobe_table_locks[KPROBE_TABLE_SIZE]; static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) -- cgit v1.2.3