From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Sebastian Siewior <bigeasy@linutronix.de>,
jbaron@akamai.com
Subject: [patch V2 21/24] jump_label: Pull get_online_cpus() into generic code
Date: Tue, 18 Apr 2017 19:05:03 +0200 [thread overview]
Message-ID: <20170418170554.121874924@linutronix.de> (raw)
In-Reply-To: 20170418170442.665445272@linutronix.de
[-- Attachment #1: jump_label_Pull_get_online_cpus_into_generic_code.patch --]
[-- Type: text/plain, Size: 4160 bytes --]
This change does two things:
- it moves the get_online_cpus() call into generic code, with the aim of
later providing some static_key ops that avoid it.
- as a side effect it inverts the lock order between cpu_hotplug_lock and
jump_label_mutex.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: jbaron@akamai.com
Cc: bigeasy@linutronix.de
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20170418103422.590118425@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
---
arch/mips/kernel/jump_label.c | 2 --
arch/sparc/kernel/jump_label.c | 2 --
arch/tile/kernel/jump_label.c | 2 --
arch/x86/kernel/jump_label.c | 2 --
kernel/jump_label.c | 14 ++++++++++++++
5 files changed, 14 insertions(+), 8 deletions(-)
--- a/arch/mips/kernel/jump_label.c
+++ b/arch/mips/kernel/jump_label.c
@@ -58,7 +58,6 @@ void arch_jump_label_transform(struct ju
insn.word = 0; /* nop */
}
- get_online_cpus();
mutex_lock(&text_mutex);
if (IS_ENABLED(CONFIG_CPU_MICROMIPS)) {
insn_p->halfword[0] = insn.word >> 16;
@@ -70,7 +69,6 @@ void arch_jump_label_transform(struct ju
(unsigned long)insn_p + sizeof(*insn_p));
mutex_unlock(&text_mutex);
- put_online_cpus();
}
#endif /* HAVE_JUMP_LABEL */
--- a/arch/sparc/kernel/jump_label.c
+++ b/arch/sparc/kernel/jump_label.c
@@ -41,12 +41,10 @@ void arch_jump_label_transform(struct ju
val = 0x01000000;
}
- get_online_cpus();
mutex_lock(&text_mutex);
*insn = val;
flushi(insn);
mutex_unlock(&text_mutex);
- put_online_cpus();
}
#endif
--- a/arch/tile/kernel/jump_label.c
+++ b/arch/tile/kernel/jump_label.c
@@ -45,14 +45,12 @@ static void __jump_label_transform(struc
void arch_jump_label_transform(struct jump_entry *e,
enum jump_label_type type)
{
- get_online_cpus();
mutex_lock(&text_mutex);
__jump_label_transform(e, type);
flush_icache_range(e->code, e->code + sizeof(tilegx_bundle_bits));
mutex_unlock(&text_mutex);
- put_online_cpus();
}
__init_or_module void arch_jump_label_transform_static(struct jump_entry *e,
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -105,11 +105,9 @@ static void __jump_label_transform(struc
void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
- get_online_cpus();
mutex_lock(&text_mutex);
__jump_label_transform(entry, type, NULL, 0);
mutex_unlock(&text_mutex);
- put_online_cpus();
}
static enum {
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -15,6 +15,7 @@
#include <linux/static_key.h>
#include <linux/jump_label_ratelimit.h>
#include <linux/bug.h>
+#include <linux/cpu.h>
#ifdef HAVE_JUMP_LABEL
@@ -124,6 +125,12 @@ void static_key_slow_inc(struct static_k
return;
}
+ /*
+ * A number of architectures need to synchronize I$ across
+ * the all CPUs, for that to be serialized against CPU hot-plug
+ * we need to avoid CPUs coming online.
+ */
+ get_online_cpus();
jump_label_lock();
if (atomic_read(&key->enabled) == 0) {
atomic_set(&key->enabled, -1);
@@ -133,6 +140,7 @@ void static_key_slow_inc(struct static_k
atomic_inc(&key->enabled);
}
jump_label_unlock();
+ put_online_cpus();
}
EXPORT_SYMBOL_GPL(static_key_slow_inc);
@@ -146,6 +154,7 @@ static void __static_key_slow_dec(struct
* returns is unbalanced, because all other static_key_slow_inc()
* instances block while the update is in progress.
*/
+ get_online_cpus();
if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
WARN(atomic_read(&key->enabled) < 0,
"jump label: negative count!\n");
@@ -159,6 +168,7 @@ static void __static_key_slow_dec(struct
jump_label_update(key);
}
jump_label_unlock();
+ put_online_cpus();
}
static void jump_label_update_timeout(struct work_struct *work)
@@ -592,6 +602,10 @@ jump_label_module_notify(struct notifier
switch (val) {
case MODULE_STATE_COMING:
+ /*
+ * XXX do we need get_online_cpus() ? the module isn't
+ * executable yet, so nothing should be looking at our code.
+ */
jump_label_lock();
ret = jump_label_add_module(mod);
if (ret) {
next prev parent reply other threads:[~2017-04-18 19:51 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-18 17:04 [patch V2 00/24] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem Thomas Gleixner
2017-04-18 17:04 ` [patch V2 01/24] cpu/hotplug: Provide cpuhp_setup/remove_state[_nocalls]_cpuslocked() Thomas Gleixner
2017-04-20 11:18 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 02/24] stop_machine: Provide stop_machine_cpuslocked() Thomas Gleixner
2017-04-20 11:19 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 03/24] padata: Make padata_alloc() static Thomas Gleixner
2017-04-20 11:19 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-04-18 17:04 ` [patch V2 04/24] padata: Avoid nested calls to get_online_cpus() in pcrypt_init_padata() Thomas Gleixner
2017-04-20 11:20 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 05/24] x86/mtrr: Remove get_online_cpus() from mtrr_save_state() Thomas Gleixner
2017-04-20 11:20 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 06/24] cpufreq: Use cpuhp_setup_state_nocalls_cpuslocked() Thomas Gleixner
2017-04-20 11:21 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 07/24] KVM/PPC/Book3S HV: " Thomas Gleixner
2017-04-20 11:21 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 08/24] hwtracing/coresight-etm3x: " Thomas Gleixner
2017-04-20 11:22 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-20 15:14 ` [patch V2 08/24] " Mathieu Poirier
2017-04-20 15:32 ` Mathieu Poirier
2017-04-18 17:04 ` [patch V2 09/24] hwtracing/coresight-etm4x: " Thomas Gleixner
2017-04-20 11:22 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 10/24] perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked() Thomas Gleixner
2017-04-20 11:23 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 11/24] ARM/hw_breakpoint: " Thomas Gleixner
2017-04-19 17:54 ` Mark Rutland
2017-04-19 18:20 ` Thomas Gleixner
2017-04-20 11:23 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 12/24] s390/kernel: Use stop_machine_cpuslocked() Thomas Gleixner
2017-04-20 11:24 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 13/24] powerpc/powernv: " Thomas Gleixner
2017-04-20 11:24 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 14/24] cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu() Thomas Gleixner
2017-04-20 11:25 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 15/24] x86/perf: Drop EXPORT of perf_check_microcode Thomas Gleixner
2017-04-20 11:25 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-04-18 17:04 ` [patch V2 16/24] perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() Thomas Gleixner
2017-04-20 11:26 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-04-18 17:04 ` [patch V2 17/24] PCI: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner
2017-04-20 11:27 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-04-18 17:05 ` [patch V2 18/24] PCI: Replace the racy recursion prevention Thomas Gleixner
2017-04-20 11:27 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-04-18 17:05 ` [patch V2 19/24] ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner
2017-04-20 11:28 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-04-18 17:05 ` [patch V2 20/24] perf/core: Remove redundant get_online_cpus() Thomas Gleixner
2017-04-20 11:28 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-04-18 17:05 ` Thomas Gleixner [this message]
2017-04-18 17:05 ` [patch V2 22/24] jump_label: Provide static_key_slow_inc_cpuslocked() Thomas Gleixner
2017-04-18 17:05 ` [patch V2 23/24] perf: Avoid cpu_hotplug_lock r-r recursion Thomas Gleixner
2017-04-18 17:05 ` [patch V2 24/24] cpu/hotplug: Convert hotplug locking to percpu rwsem Thomas Gleixner
2017-04-20 11:30 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-10 4:59 ` [patch V2 24/24] " Michael Ellerman
2017-05-10 8:49 ` Thomas Gleixner
2017-05-10 16:30 ` Steven Rostedt
2017-05-10 17:15 ` Steven Rostedt
2017-05-11 5:49 ` Michael Ellerman
2017-04-25 16:10 ` [patch V2 00/24] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem Mark Rutland
2017-04-25 17:28 ` Sebastian Siewior
2017-04-26 8:59 ` Mark Rutland
2017-04-26 9:40 ` Suzuki K Poulose
2017-04-26 10:32 ` Mark Rutland
2017-04-27 8:27 ` Sebastian Siewior
2017-04-27 9:57 ` Mark Rutland
2017-04-27 10:01 ` Thomas Gleixner
2017-04-27 12:30 ` Mark Rutland
2017-04-27 15:48 ` [PATCH] arm64: cpufeature: use static_branch_enable_cpuslocked() (was: Re: [patch V2 00/24] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem) Mark Rutland
2017-04-27 16:35 ` Suzuki K Poulose
2017-04-27 17:03 ` [PATCH] arm64: cpufeature: use static_branch_enable_cpuslocked() Suzuki K Poulose
2017-04-27 17:17 ` Mark Rutland
2017-04-28 14:24 ` [RFC PATCH] trace/perf: cure locking issue in perf_event_open() error path Sebastian Siewior
2017-04-28 14:27 ` Sebastian Siewior
2017-05-01 12:57 ` [tip:smp/hotplug] perf: Reorder cpu hotplug rwsem against cred_guard_mutex tip-bot for Thomas Gleixner
2017-05-01 12:58 ` [tip:smp/hotplug] perf: Push hotplug protection down to callers tip-bot for Thomas Gleixner
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