Dear RT folks!
I'm pleased to announce the v5.10.16-rt30 patch set.
Changes since v5.10.16-rt29:
- Due to recent softirq rework it was not possible to compile a kernel
with RT && !SMP. Reported by Jonathan Schwender, patch by Christian
Eggers.
- Update the block-mq patches to the version, that has been staged for
upstream.
Known issues
- kdb/kgdb can easily deadlock.
- kmsg dumpers expecting not to be called in parallel can clobber
their temp buffer.
- netconsole triggers WARN.
The delta patch against v5.10.16-rt29 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.10/incr/patch-5.10.16-rt29-rt30.patch.xz
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
v5.10.16-rt30
The RT patch against v5.10.16 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patch-5.10.16-rt30.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.16-rt30.tar.xz
Sebastian
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5b27fd6c8c7c2..b293f74ea8cad 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -565,15 +565,12 @@ void blk_mq_end_request(struct request *rq, blk_status_t
error)
}
EXPORT_SYMBOL(blk_mq_end_request);
-static void blk_complete_reqs(struct llist_head *cpu_list)
+static void blk_complete_reqs(struct llist_head *list)
{
- struct llist_node *entry;
- struct request *rq, *rq_next;
+ struct llist_node *entry = llist_reverse_order(llist_del_all(list));
+ struct request *rq, *next;
- entry = llist_del_all(cpu_list);
- entry = llist_reverse_order(entry);
-
- llist_for_each_entry_safe(rq, rq_next, entry, ipi_list)
+ llist_for_each_entry_safe(rq, next, entry, ipi_list)
rq->q->mq_ops->complete(rq);
}
@@ -619,9 +616,34 @@ static inline bool blk_mq_complete_need_ipi(struct request
*rq)
return cpu_online(rq->mq_ctx->cpu);
}
+static void blk_mq_complete_send_ipi(struct request *rq)
+{
+ struct llist_head *list;
+ unsigned int cpu;
+
+ cpu = rq->mq_ctx->cpu;
+ list = &per_cpu(blk_cpu_done, cpu);
+ if (llist_add(&rq->ipi_list, list)) {
+ rq->csd.func = __blk_mq_complete_request_remote;
+ rq->csd.info = rq;
+ rq->csd.flags = 0;
+ smp_call_function_single_async(cpu, &rq->csd);
+ }
+}
+
+static void blk_mq_raise_softirq(struct request *rq)
+{
+ struct llist_head *list;
+
+ preempt_disable();
+ list = this_cpu_ptr(&blk_cpu_done);
+ if (llist_add(&rq->ipi_list, list))
+ raise_softirq(BLOCK_SOFTIRQ);
+ preempt_enable();
+}
+
bool blk_mq_complete_request_remote(struct request *rq)
{
- struct llist_head *cpu_list;
WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
/*
@@ -632,27 +654,15 @@ bool blk_mq_complete_request_remote(struct request *rq)
return false;
if (blk_mq_complete_need_ipi(rq)) {
- unsigned int cpu;
-
- cpu = rq->mq_ctx->cpu;
- cpu_list = &per_cpu(blk_cpu_done, cpu);
- if (llist_add(&rq->ipi_list, cpu_list)) {
- rq->csd.func = __blk_mq_complete_request_remote;
- rq->csd.flags = 0;
- smp_call_function_single_async(cpu, &rq->csd);
- }
- } else {
- if (rq->q->nr_hw_queues > 1)
- return false;
-
- preempt_disable();
- cpu_list = this_cpu_ptr(&blk_cpu_done);
- if (llist_add(&rq->ipi_list, cpu_list))
- raise_softirq(BLOCK_SOFTIRQ);
- preempt_enable();
+ blk_mq_complete_send_ipi(rq);
+ return true;
}
- return true;
+ if (rq->q->nr_hw_queues == 1) {
+ blk_mq_raise_softirq(rq);
+ return true;
+ }
+ return false;
}
EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
diff --git a/kernel/smp.c b/kernel/smp.c
index 4d17501433be7..23778281aaa70 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -14,6 +14,7 @@
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/init.h>
+#include <linux/interrupt.h>
#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/cpu.h>
@@ -449,6 +450,19 @@ void flush_smp_call_function_from_idle(void)
local_irq_save(flags);
flush_smp_call_function_queue(true);
+
+ if (local_softirq_pending()) {
+
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+ do_softirq();
+ } else {
+ struct task_struct *ksoftirqd = this_cpu_ksoftirqd();
+
+ if (ksoftirqd && ksoftirqd->state != TASK_RUNNING)
+ wake_up_process(ksoftirqd);
+ }
+ }
+
local_irq_restore(flags);
}
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 3efa760417280..f0074f1344402 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -867,7 +867,7 @@ void tasklet_kill(struct tasklet_struct *t)
}
EXPORT_SYMBOL(tasklet_kill);
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
void tasklet_unlock(struct tasklet_struct *t)
{
smp_mb__before_atomic();
diff --git a/localversion-rt b/localversion-rt
index 90290c642ed52..b72862e06be43 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt29
+-rt30
