From: tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: hpa@zytor.com, mingo@kernel.org, bigeasy@linutronix.de,
tglx@linutronix.de, linux-kernel@vger.kernel.org,
rostedt@goodmis.org
Subject: [tip:smp/hotplug] tracing/rb: Convert to hotplug state machine
Date: Thu, 1 Dec 2016 16:10:28 -0800 [thread overview]
Message-ID: <tip-b32614c03413f8a6025d8677c2b7c0ee976e63d4@git.kernel.org> (raw)
In-Reply-To: <20161126231350.10321-7-bigeasy@linutronix.de>
Commit-ID: b32614c03413f8a6025d8677c2b7c0ee976e63d4
Gitweb: http://git.kernel.org/tip/b32614c03413f8a6025d8677c2b7c0ee976e63d4
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Sun, 27 Nov 2016 00:13:34 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 2 Dec 2016 00:52:34 +0100
tracing/rb: Convert to hotplug state machine
Install the callbacks via the state machine. The notifier in struct
ring_buffer is replaced by the multi instance interface. Upon
__ring_buffer_alloc() invocation, cpuhp_state_add_instance() will invoke
the trace_rb_cpu_prepare() on each CPU.
This callback may now fail. This means __ring_buffer_alloc() will fail and
cleanup (like previously) and during a CPU up event this failure will not
allow the CPU to come up.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161126231350.10321-7-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/cpuhotplug.h | 1 +
include/linux/ring_buffer.h | 6 ++
kernel/trace/ring_buffer.c | 135 +++++++++++++++-----------------------------
kernel/trace/trace.c | 15 ++++-
4 files changed, 66 insertions(+), 91 deletions(-)
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index e3771fb..18bcfeb 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -62,6 +62,7 @@ enum cpuhp_state {
CPUHP_TOPOLOGY_PREPARE,
CPUHP_NET_IUCV_PREPARE,
CPUHP_ARM_BL_PREPARE,
+ CPUHP_TRACE_RB_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 4acc552..b6d4568 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -198,4 +198,10 @@ enum ring_buffer_flags {
RB_FL_OVERWRITE = 1 << 0,
};
+#ifdef CONFIG_RING_BUFFER
+int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node);
+#else
+#define trace_rb_cpu_prepare NULL
+#endif
+
#endif /* _LINUX_RING_BUFFER_H */
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 9c14373..a7a055f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -479,9 +479,7 @@ struct ring_buffer {
struct ring_buffer_per_cpu **buffers;
-#ifdef CONFIG_HOTPLUG_CPU
- struct notifier_block cpu_notify;
-#endif
+ struct hlist_node node;
u64 (*clock)(void);
struct rb_irq_work irq_work;
@@ -1274,11 +1272,6 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
kfree(cpu_buffer);
}
-#ifdef CONFIG_HOTPLUG_CPU
-static int rb_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu);
-#endif
-
/**
* __ring_buffer_alloc - allocate a new ring_buffer
* @size: the size in bytes per cpu that is needed.
@@ -1296,6 +1289,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
long nr_pages;
int bsize;
int cpu;
+ int ret;
/* keep it in its own cache line */
buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
@@ -1318,17 +1312,6 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
if (nr_pages < 2)
nr_pages = 2;
- /*
- * In case of non-hotplug cpu, if the ring-buffer is allocated
- * in early initcall, it will not be notified of secondary cpus.
- * In that off case, we need to allocate for all possible cpus.
- */
-#ifdef CONFIG_HOTPLUG_CPU
- cpu_notifier_register_begin();
- cpumask_copy(buffer->cpumask, cpu_online_mask);
-#else
- cpumask_copy(buffer->cpumask, cpu_possible_mask);
-#endif
buffer->cpus = nr_cpu_ids;
bsize = sizeof(void *) * nr_cpu_ids;
@@ -1337,19 +1320,15 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
if (!buffer->buffers)
goto fail_free_cpumask;
- for_each_buffer_cpu(buffer, cpu) {
- buffer->buffers[cpu] =
- rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
- if (!buffer->buffers[cpu])
- goto fail_free_buffers;
- }
+ cpu = raw_smp_processor_id();
+ cpumask_set_cpu(cpu, buffer->cpumask);
+ buffer->buffers[cpu] = rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
+ if (!buffer->buffers[cpu])
+ goto fail_free_buffers;
-#ifdef CONFIG_HOTPLUG_CPU
- buffer->cpu_notify.notifier_call = rb_cpu_notify;
- buffer->cpu_notify.priority = 0;
- __register_cpu_notifier(&buffer->cpu_notify);
- cpu_notifier_register_done();
-#endif
+ ret = cpuhp_state_add_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
+ if (ret < 0)
+ goto fail_free_buffers;
mutex_init(&buffer->mutex);
@@ -1364,9 +1343,6 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
fail_free_cpumask:
free_cpumask_var(buffer->cpumask);
-#ifdef CONFIG_HOTPLUG_CPU
- cpu_notifier_register_done();
-#endif
fail_free_buffer:
kfree(buffer);
@@ -1383,18 +1359,11 @@ ring_buffer_free(struct ring_buffer *buffer)
{
int cpu;
-#ifdef CONFIG_HOTPLUG_CPU
- cpu_notifier_register_begin();
- __unregister_cpu_notifier(&buffer->cpu_notify);
-#endif
+ cpuhp_state_remove_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
for_each_buffer_cpu(buffer, cpu)
rb_free_cpu_buffer(buffer->buffers[cpu]);
-#ifdef CONFIG_HOTPLUG_CPU
- cpu_notifier_register_done();
-#endif
-
kfree(buffer->buffers);
free_cpumask_var(buffer->cpumask);
@@ -4633,62 +4602,48 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
}
EXPORT_SYMBOL_GPL(ring_buffer_read_page);
-#ifdef CONFIG_HOTPLUG_CPU
-static int rb_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+/*
+ * We only allocate new buffers, never free them if the CPU goes down.
+ * If we were to free the buffer, then the user would lose any trace that was in
+ * the buffer.
+ */
+int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node)
{
- struct ring_buffer *buffer =
- container_of(self, struct ring_buffer, cpu_notify);
- long cpu = (long)hcpu;
+ struct ring_buffer *buffer;
long nr_pages_same;
int cpu_i;
unsigned long nr_pages;
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- if (cpumask_test_cpu(cpu, buffer->cpumask))
- return NOTIFY_OK;
-
- nr_pages = 0;
- nr_pages_same = 1;
- /* check if all cpu sizes are same */
- for_each_buffer_cpu(buffer, cpu_i) {
- /* fill in the size from first enabled cpu */
- if (nr_pages == 0)
- nr_pages = buffer->buffers[cpu_i]->nr_pages;
- if (nr_pages != buffer->buffers[cpu_i]->nr_pages) {
- nr_pages_same = 0;
- break;
- }
- }
- /* allocate minimum pages, user can later expand it */
- if (!nr_pages_same)
- nr_pages = 2;
- buffer->buffers[cpu] =
- rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
- if (!buffer->buffers[cpu]) {
- WARN(1, "failed to allocate ring buffer on CPU %ld\n",
- cpu);
- return NOTIFY_OK;
+ buffer = container_of(node, struct ring_buffer, node);
+ if (cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ nr_pages = 0;
+ nr_pages_same = 1;
+ /* check if all cpu sizes are same */
+ for_each_buffer_cpu(buffer, cpu_i) {
+ /* fill in the size from first enabled cpu */
+ if (nr_pages == 0)
+ nr_pages = buffer->buffers[cpu_i]->nr_pages;
+ if (nr_pages != buffer->buffers[cpu_i]->nr_pages) {
+ nr_pages_same = 0;
+ break;
}
- smp_wmb();
- cpumask_set_cpu(cpu, buffer->cpumask);
- break;
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- /*
- * Do nothing.
- * If we were to free the buffer, then the user would
- * lose any trace that was in the buffer.
- */
- break;
- default:
- break;
}
- return NOTIFY_OK;
+ /* allocate minimum pages, user can later expand it */
+ if (!nr_pages_same)
+ nr_pages = 2;
+ buffer->buffers[cpu] =
+ rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
+ if (!buffer->buffers[cpu]) {
+ WARN(1, "failed to allocate ring buffer on CPU %u\n",
+ cpu);
+ return -ENOMEM;
+ }
+ smp_wmb();
+ cpumask_set_cpu(cpu, buffer->cpumask);
+ return 0;
}
-#endif
#ifdef CONFIG_RING_BUFFER_STARTUP_TEST
/*
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8696ce6..465d56f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7659,10 +7659,21 @@ __init static int tracer_alloc_buffers(void)
raw_spin_lock_init(&global_trace.start_lock);
+ /*
+ * The prepare callbacks allocates some memory for the ring buffer. We
+ * don't free the buffer if the if the CPU goes down. If we were to free
+ * the buffer, then the user would lose any trace that was in the
+ * buffer. The memory will be removed once the "instance" is removed.
+ */
+ ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
+ "trace/RB:preapre", trace_rb_cpu_prepare,
+ NULL);
+ if (ret < 0)
+ goto out_free_cpumask;
/* Used for event triggers */
temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
if (!temp_buffer)
- goto out_free_cpumask;
+ goto out_rm_hp_state;
if (trace_create_savedcmd() < 0)
goto out_free_temp_buffer;
@@ -7723,6 +7734,8 @@ out_free_savedcmd:
free_saved_cmdlines_buffer(savedcmd);
out_free_temp_buffer:
ring_buffer_free(temp_buffer);
+out_rm_hp_state:
+ cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
out_free_cpumask:
free_cpumask_var(global_trace.tracing_cpumask);
out_free_buffer_mask:
next prev parent reply other threads:[~2016-12-02 0:10 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-26 23:13 cpu hotplug: convert more drivers (batch #6 and last) Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 01/22] cpufreq/acpi-cpufreq: Convert to hotplug state machine Sebastian Andrzej Siewior
2016-11-28 5:15 ` Viresh Kumar
2016-11-28 9:49 ` Sebastian Andrzej Siewior
2016-11-28 9:51 ` [PATCH 01/22 v2] " Sebastian Andrzej Siewior
2016-11-28 9:54 ` Viresh Kumar
2016-11-28 12:46 ` Rafael J. Wysocki
2016-11-26 23:13 ` [PATCH 02/22] cpufreq/acpi-cpufreq: drop rdmsr_on_cpus() usage Sebastian Andrzej Siewior
2016-11-28 9:52 ` [PATCH 02/22 v2] " Sebastian Andrzej Siewior
2016-11-28 9:54 ` Viresh Kumar
2016-11-26 23:13 ` [PATCH 03/22] idle/intel: Remove superfluous SMP fuction call Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 04/22] idle/intel: Convert to hotplug state machine Sebastian Andrzej Siewior
2016-11-28 17:29 ` Thomas Gleixner
2016-11-29 9:40 ` Sebastian Andrzej Siewior
2016-11-29 9:51 ` [PATCH 04/22 v2] " Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 05/22] oprofile/nmi timer: " Sebastian Andrzej Siewior
2016-12-02 0:09 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 06/22] tracing/rb: " Sebastian Andrzej Siewior
2016-12-02 0:10 ` tip-bot for Sebastian Andrzej Siewior [this message]
2016-12-07 11:15 ` [linux-next] tracing/rb: NULL pointer dereference at trace_rb_cpu_prepare() Tetsuo Handa
2016-12-07 13:31 ` [PATCH] tracing/rb: init the CPU mask on allocation Sebastian Andrzej Siewior
2016-12-07 13:43 ` [tip:smp/hotplug] tracing/rb: Init " tip-bot for Sebastian Andrzej Siewior
2016-12-07 14:33 ` [PATCH] tracing/rb: init " Tetsuo Handa
2016-11-26 23:13 ` [PATCH 07/22] mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead() Sebastian Andrzej Siewior
2016-11-28 9:24 ` Michal Hocko
2016-12-02 0:10 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 08/22] mm/vmstat: Avoid on each online CPU loops Sebastian Andrzej Siewior
2016-11-28 9:28 ` Michal Hocko
2016-11-29 14:08 ` Thomas Gleixner
2016-11-29 14:44 ` Michal Hocko
2016-11-29 14:51 ` [PATCH 08/22 v2] " Sebastian Andrzej Siewior
2016-11-29 15:20 ` Michal Hocko
2016-12-02 0:11 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 09/22] mm/vmstat: Convert to hotplug state machine Sebastian Andrzej Siewior
2016-11-29 14:52 ` [PATCH 09/22 v2] " Sebastian Andrzej Siewior
2016-12-02 0:11 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 10/22] mm/zsmalloc: " Sebastian Andrzej Siewior
2016-12-02 0:12 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 11/22] mm/zswap: Convert dst-mem " Sebastian Andrzej Siewior
2016-12-02 0:12 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 12/22] mm/zswap: Convert pool " Sebastian Andrzej Siewior
2016-12-02 0:13 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 13/22] iommu/vt-d: Convert " Sebastian Andrzej Siewior
2016-12-02 0:13 ` [tip:smp/hotplug] " tip-bot for Anna-Maria Gleixner
2016-11-26 23:13 ` [PATCH 14/22] mm/compaction: " Sebastian Andrzej Siewior
2016-12-02 0:14 ` [tip:smp/hotplug] " tip-bot for Anna-Maria Gleixner
2016-11-26 23:13 ` [PATCH 15/22] arm64/cpuinfo: Make hotplug notifier symmetric Sebastian Andrzej Siewior
2016-11-29 17:22 ` Suzuki K Poulose
2016-12-02 0:14 ` [tip:smp/hotplug] " tip-bot for Anna-Maria Gleixner
2016-11-26 23:13 ` [PATCH 16/22] arm64/cpuinfo: Convert to hotplug state machine Sebastian Andrzej Siewior
2016-11-29 17:26 ` Suzuki K Poulose
2016-12-02 0:15 ` [tip:smp/hotplug] " tip-bot for Anna-Maria Gleixner
2016-11-26 23:13 ` [PATCH 17/22] KVM/PPC/Book3S HV: " Sebastian Andrzej Siewior
2016-12-02 0:15 ` [tip:smp/hotplug] " tip-bot for Anna-Maria Gleixner
2016-11-26 23:13 ` [PATCH 18/22] zram: " Sebastian Andrzej Siewior
2016-12-02 0:16 ` [tip:smp/hotplug] " tip-bot for Anna-Maria Gleixner
2016-11-26 23:13 ` [PATCH 19/22] soc/fsl/qbman: " Sebastian Andrzej Siewior
2016-12-02 0:16 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 20/22] " Sebastian Andrzej Siewior
2016-12-02 0:17 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 21/22] staging/lustre/libcfs: " Sebastian Andrzej Siewior
2016-12-02 10:18 ` [PATCH 21/22 v2] " Sebastian Andrzej Siewior
2016-12-02 10:42 ` Greg Kroah-Hartman
2016-12-02 11:00 ` [PATCH 21/22 v3] " Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 22/22] Remove obsolete cpu hotplug register / unregister functions Sebastian Andrzej Siewior
2016-12-21 19:19 [patch 00/10] cpu/hotplug: Final cleanup Thomas Gleixner
2016-12-21 19:19 ` [patch 01/10] ARM: imx: mmcd: Fix broken cpu hotplug handling Thomas Gleixner
2016-12-22 20:18 ` [tip:smp/urgent] ARM/imx/mmcd: " tip-bot for Thomas Gleixner
2016-12-25 10:02 ` tip-bot for Thomas Gleixner
2016-12-21 19:19 ` [patch 02/10] cpu/hotplug: Prevent overwriting of callbacks Thomas Gleixner
2016-12-22 11:07 ` Thomas Gleixner
2016-12-26 23:04 ` ojab
2016-12-26 23:12 ` ojab
2016-12-22 20:21 ` [tip:smp/urgent] " tip-bot for Thomas Gleixner
2016-12-25 10:04 ` tip-bot for Thomas Gleixner
2016-12-21 19:19 ` [patch 03/10] scsi/bnx2fc: Convert to hotplug state machine Thomas Gleixner
2016-12-22 20:21 ` [tip:smp/urgent] " tip-bot for Sebastian Andrzej Siewior
2016-12-25 10:05 ` tip-bot for Sebastian Andrzej Siewior
2016-12-21 19:19 ` [patch 04/10] scsi/bnx2i: " Thomas Gleixner
2016-12-22 20:22 ` [tip:smp/urgent] " tip-bot for Sebastian Andrzej Siewior
2016-12-25 10:05 ` tip-bot for Sebastian Andrzej Siewior
2016-12-21 19:19 ` [patch 05/10] staging/lustre/libcfs: " Thomas Gleixner
2016-12-22 20:22 ` [tip:smp/urgent] " tip-bot for Anna-Maria Gleixner
2016-12-25 10:06 ` tip-bot for Anna-Maria Gleixner
2016-12-21 19:19 ` [patch 06/10] cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions Thomas Gleixner
2016-12-22 20:23 ` [tip:smp/urgent] " tip-bot for Thomas Gleixner
2016-12-25 10:06 ` tip-bot for Thomas Gleixner
2016-12-21 19:19 ` [patch 07/10] cpu/hotplug: Cleanup state names Thomas Gleixner
2016-12-22 20:23 ` [tip:smp/urgent] " tip-bot for Thomas Gleixner
2016-12-25 10:07 ` tip-bot for Thomas Gleixner
2016-12-21 19:19 ` [patch 08/10] coresight: etm3/4x: Consolidate hotplug state space Thomas Gleixner
2016-12-22 16:30 ` Mathieu Poirier
2016-12-22 20:24 ` [tip:smp/urgent] coresight/etm3/4x: " tip-bot for Thomas Gleixner
2016-12-25 10:07 ` tip-bot for Thomas Gleixner
2016-12-21 19:19 ` [patch 09/10] irqchip/gic: " Thomas Gleixner
2016-12-22 20:24 ` [tip:smp/urgent] " tip-bot for Thomas Gleixner
2016-12-25 10:08 ` tip-bot for Thomas Gleixner
2016-12-21 19:19 ` [patch 10/10] irqchip/armada-xp: " Thomas Gleixner
2016-12-21 20:22 ` Thomas Petazzoni
2016-12-21 20:27 ` Thomas Gleixner
2016-12-22 20:25 ` [tip:smp/urgent] " tip-bot for Thomas Gleixner
2016-12-25 10:08 ` tip-bot for Thomas Gleixner
2016-12-22 17:59 ` [patch 00/10] cpu/hotplug: Final cleanup Sam Ravnborg
2016-12-27 11:17 ` Thomas Gleixner
2016-12-27 19:41 ` Sam Ravnborg
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