159 lines
4.7 KiB
Diff
159 lines
4.7 KiB
Diff
From a583b75cab964e833c5031f86eb95d3caed27398 Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Sun, 13 Nov 2011 17:17:09 +0100
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Subject: [PATCH 260/267] softirq: Check preemption after reenabling
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interrupts
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raise_softirq_irqoff() disables interrupts and wakes the softirq
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daemon, but after reenabling interrupts there is no preemption check,
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so the execution of the softirq thread might be delayed arbitrarily.
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In principle we could add that check to local_irq_enable/restore, but
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that's overkill as the rasie_softirq_irqoff() sections are the only
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ones which show this behaviour.
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Reported-by: Carsten Emde <cbe@osadl.org>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: stable-rt@vger.kernel.org
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---
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block/blk-iopoll.c | 3 +++
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block/blk-softirq.c | 3 +++
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include/linux/preempt.h | 3 +++
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net/core/dev.c | 6 ++++++
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4 files changed, 15 insertions(+)
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diff --git a/block/blk-iopoll.c b/block/blk-iopoll.c
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index 58916af..f7ca9b4 100644
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--- a/block/blk-iopoll.c
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+++ b/block/blk-iopoll.c
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@@ -38,6 +38,7 @@ void blk_iopoll_sched(struct blk_iopoll *iop)
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list_add_tail(&iop->list, &__get_cpu_var(blk_cpu_iopoll));
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__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
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local_irq_restore(flags);
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+ preempt_check_resched_rt();
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}
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EXPORT_SYMBOL(blk_iopoll_sched);
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@@ -135,6 +136,7 @@ static void blk_iopoll_softirq(struct softirq_action *h)
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__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
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local_irq_enable();
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+ preempt_check_resched_rt();
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}
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/**
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@@ -204,6 +206,7 @@ static int __cpuinit blk_iopoll_cpu_notify(struct notifier_block *self,
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&__get_cpu_var(blk_cpu_iopoll));
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__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
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local_irq_enable();
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+ preempt_check_resched_rt();
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}
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return NOTIFY_OK;
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diff --git a/block/blk-softirq.c b/block/blk-softirq.c
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index 1366a89..60a88ab 100644
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--- a/block/blk-softirq.c
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+++ b/block/blk-softirq.c
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@@ -50,6 +50,7 @@ static void trigger_softirq(void *data)
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raise_softirq_irqoff(BLOCK_SOFTIRQ);
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local_irq_restore(flags);
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+ preempt_check_resched_rt();
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}
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/*
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@@ -92,6 +93,7 @@ static int __cpuinit blk_cpu_notify(struct notifier_block *self,
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&__get_cpu_var(blk_cpu_done));
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raise_softirq_irqoff(BLOCK_SOFTIRQ);
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local_irq_enable();
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+ preempt_check_resched_rt();
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}
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return NOTIFY_OK;
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@@ -150,6 +152,7 @@ do_local:
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goto do_local;
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local_irq_restore(flags);
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+ preempt_check_resched_rt();
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}
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/**
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diff --git a/include/linux/preempt.h b/include/linux/preempt.h
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index 6450c01..58d8982 100644
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--- a/include/linux/preempt.h
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+++ b/include/linux/preempt.h
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@@ -56,8 +56,10 @@ do { \
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#ifndef CONFIG_PREEMPT_RT_BASE
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# define preempt_enable_no_resched() __preempt_enable_no_resched()
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+# define preempt_check_resched_rt() do { } while (0)
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#else
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# define preempt_enable_no_resched() preempt_enable()
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+# define preempt_check_resched_rt() preempt_check_resched()
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#endif
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#define preempt_enable() \
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@@ -105,6 +107,7 @@ do { \
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#define preempt_disable_notrace() do { } while (0)
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#define preempt_enable_no_resched_notrace() do { } while (0)
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#define preempt_enable_notrace() do { } while (0)
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+#define preempt_check_resched_rt() do { } while (0)
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#endif /* CONFIG_PREEMPT_COUNT */
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diff --git a/net/core/dev.c b/net/core/dev.c
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index ae4fd5e..3756e96 100644
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--- a/net/core/dev.c
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+++ b/net/core/dev.c
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@@ -1779,6 +1779,7 @@ static inline void __netif_reschedule(struct Qdisc *q)
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sd->output_queue_tailp = &q->next_sched;
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raise_softirq_irqoff(NET_TX_SOFTIRQ);
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local_irq_restore(flags);
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+ preempt_check_resched_rt();
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}
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void __netif_schedule(struct Qdisc *q)
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@@ -1800,6 +1801,7 @@ void dev_kfree_skb_irq(struct sk_buff *skb)
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sd->completion_queue = skb;
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raise_softirq_irqoff(NET_TX_SOFTIRQ);
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local_irq_restore(flags);
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+ preempt_check_resched_rt();
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}
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}
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EXPORT_SYMBOL(dev_kfree_skb_irq);
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@@ -2969,6 +2971,7 @@ enqueue:
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rps_unlock(sd);
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local_irq_restore(flags);
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+ preempt_check_resched_rt();
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atomic_long_inc(&skb->dev->rx_dropped);
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kfree_skb(skb);
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@@ -3790,6 +3793,7 @@ static void net_rps_action_and_irq_enable(struct softnet_data *sd)
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} else
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#endif
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local_irq_enable();
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+ preempt_check_resched_rt();
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}
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static int process_backlog(struct napi_struct *napi, int quota)
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@@ -3862,6 +3866,7 @@ void __napi_schedule(struct napi_struct *n)
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local_irq_save(flags);
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____napi_schedule(&__get_cpu_var(softnet_data), n);
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local_irq_restore(flags);
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+ preempt_check_resched_rt();
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}
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EXPORT_SYMBOL(__napi_schedule);
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@@ -6402,6 +6407,7 @@ static int dev_cpu_callback(struct notifier_block *nfb,
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raise_softirq_irqoff(NET_TX_SOFTIRQ);
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local_irq_enable();
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+ preempt_check_resched_rt();
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/* Process offline CPU's input_pkt_queue */
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while ((skb = __skb_dequeue(&oldsd->process_queue))) {
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--
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1.7.10
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