SRCU changes for 3.20
Subsystems (29)
cover SRCU changes for 3.20
Hello!
This series contains some minor changes to SRCU:
1. Expand SRCU ->completed to 64 bits. This is to be consistent with
rcutorture, which now pays attention to this field for more precise error checking.
2. Combine DEFINE_SRCU() and DEFINE_STATIC_SRCU().
3. Make SRCU optional via a new CONFIG_SRCU Kconfig parameter,
courtesy of Pranith Kumar. This saves about 2KB.
Thanx, Paul
------------------------------------------------------------------------
b/arch/arm/kvm/Kconfig | 1 + b/arch/arm64/kvm/Kconfig | 1 + b/arch/mips/kvm/Kconfig | 1 + b/arch/powerpc/kvm/Kconfig | 1 + b/arch/s390/kvm/Kconfig | 1 + b/arch/tile/kvm/Kconfig | 1 + b/arch/x86/Kconfig | 1 + b/arch/x86/kvm/Kconfig | 1 + b/drivers/clk/Kconfig | 1 + b/drivers/cpufreq/Kconfig | 1 + b/drivers/devfreq/Kconfig | 1 + b/drivers/md/Kconfig | 1 + b/drivers/net/Kconfig | 1 + b/fs/btrfs/Kconfig | 1 + b/fs/notify/Kconfig | 1 + b/fs/quota/Kconfig | 1 + b/include/linux/srcu.h | 14 ++++++-------- b/init/Kconfig | 9 +++++++++ b/kernel/notifier.c | 3 +++ b/kernel/power/Kconfig | 1 + b/kernel/rcu/Makefile | 3 ++- b/kernel/rcu/srcu.c | 2 +- b/lib/Kconfig.debug | 1 + b/mm/Kconfig | 1 + b/security/tomoyo/Kconfig | 1 + 25 files changed, 41 insertions(+), 10 deletions(-)
PATCH 1/3 rcu: Expand SRCU ->completed to 64 bits
From: "Paul E. McKenney" <[email protected]>
When rcutorture used only the low-order 32 bits of the grace-period number, it was not a problem for SRCU to use a 32-bit completed field. However, rcutorture now uses the full 64 bits on 64-bit systems, so this commit converts SRCU's ->completed field to unsigned long so as to provide 64 bits on 64-bit systems.
Signed-off-by Paul E. McKenney <[email protected]>
--- include/linux/srcu.h | 4 ++-- kernel/rcu/srcu.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)
include/linux/srcu.h +2 -2
@@ -45,7 +45,7 @@ struct rcu_batch {#define RCU_BATCH_INIT (name) { NULL, &(name.head) }struct srcu_struct { -unsigned completed; +unsigned long completed;struct srcu_struct_array __percpu *per_cpu_ref;spinlock_t queue_lock;/* protect ->batch_queue, ->running */ bool running;
@@ -135,7 +135,7 @@ int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp); void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);void synchronize_srcu (struct srcu_struct *sp);void synchronize_srcu_expedited (struct srcu_struct *sp); -long srcu_batches_completed (struct srcu_struct *sp); +unsigned long srcu_batches_completed (struct srcu_struct *sp);void srcu_barrier (struct srcu_struct *sp);#ifdef CONFIG_DEBUG_LOCK_ALLOC
kernel/rcu/srcu.c +1 -1
@@ -546,7 +546,7 @@ EXPORT_SYMBOL_GPL(srcu_barrier);* Report the number of batches, correlated with, but not necessarily * precisely the same as, the number of grace periods that have elapsed. */ -long srcu_batches_completed (struct srcu_struct *sp) +unsigned long srcu_batches_completed (struct srcu_struct *sp) {return sp->completed; }
Signature · 1 line
1.8.1.5
PATCH 3/3 rcu: Make SRCU optional by using CONFIG_SRCU
From: Pranith Kumar <[email protected]>
SRCU is not necessary to be compiled by default in all cases. For tinification efforts not compiling SRCU unless necessary is desirable.
The current patch tries to make compiling SRCU optional by introducing a new Kconfig option CONFIG_SRCU which is selected when any of the components making use of SRCU are selected.
If we do not select CONFIG_SRCU, srcu.o will not be compiled at all.
text data bss dec hex filename
2007 0 0 2007 7d7 kernel/rcu/srcu.o
Size of arch/powerpc/boot/zImage changes from
text data bss dec hex filename
831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before 829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : after
so the savings are about ~2000 bytes.
Signed-off-by Pranith Kumar <[email protected]>
CC Paul E. McKenney <[email protected]>
CC Josh Triplett <[email protected]>
CC Lai Jiangshan <[email protected]>
Signed-off-by Paul E. McKenney <[email protected]>
[ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
--- arch/arm/kvm/Kconfig | 1 + arch/arm64/kvm/Kconfig | 1 + arch/mips/kvm/Kconfig | 1 + arch/powerpc/kvm/Kconfig | 1 + arch/s390/kvm/Kconfig | 1 + arch/tile/kvm/Kconfig | 1 + arch/x86/Kconfig | 1 + arch/x86/kvm/Kconfig | 1 + drivers/clk/Kconfig | 1 + drivers/cpufreq/Kconfig | 1 + drivers/devfreq/Kconfig | 1 + drivers/md/Kconfig | 1 + drivers/net/Kconfig | 1 + fs/btrfs/Kconfig | 1 + fs/notify/Kconfig | 1 + fs/quota/Kconfig | 1 + init/Kconfig | 9 +++++++++ kernel/notifier.c | 3 +++ kernel/power/Kconfig | 1 + kernel/rcu/Makefile | 3 ++- lib/Kconfig.debug | 1 + mm/Kconfig | 1 + security/tomoyo/Kconfig | 1 + 23 files changed, 34 insertions(+), 1 deletion(-)
arch/arm/kvm/Kconfig +1 -0
@@ -23,6 +23,7 @@ config KVM select HAVE_KVM_CPU_RELAX_INTERCEPT select KVM_MMIO select KVM_ARM_HOST + select SRCU depends on ARM_VIRT_EXT && ARM_LPAE ---help--- Support hosting virtualized guest machines. You will also
arch/arm64/kvm/Kconfig +1 -0
@@ -26,6 +26,7 @@ config KVM select KVM_ARM_HOST select KVM_ARM_VGIC select KVM_ARM_TIMER + select SRCU ---help--- Support hosting virtualized guest machines.
arch/mips/kvm/Kconfig +1 -0
@@ -20,6 +20,7 @@ config KVM select PREEMPT_NOTIFIERS select ANON_INODES select KVM_MMIO + select SRCU ---help--- Support for hosting Guest kernels. Currently supported on MIPS32 processors.
arch/powerpc/kvm/Kconfig +1 -0
@@ -21,6 +21,7 @@ config KVM select PREEMPT_NOTIFIERS select ANON_INODES select HAVE_KVM_EVENTFD + select SRCU config KVM_BOOK3S_HANDLER bool
arch/s390/kvm/Kconfig +1 -0
@@ -28,6 +28,7 @@ config KVM select HAVE_KVM_IRQCHIP select HAVE_KVM_IRQFD select HAVE_KVM_IRQ_ROUTING + select SRCU ---help--- Support hosting paravirtualized guest machines using the SIE virtualization capability on the mainframe. This should work
arch/tile/kvm/Kconfig +1 -0
@@ -21,6 +21,7 @@ config KVM depends on HAVE_KVM && MODULES select PREEMPT_NOTIFIERS select ANON_INODES + select SRCU ---help--- Support hosting paravirtualized guest machines.
arch/x86/Kconfig +1 -0
@@ -138,6 +138,7 @@ config X86 select HAVE_ACPI_APEI_NMI if ACPI select ACPI_LEGACY_TABLES_LOOKUP if ACPI select X86_FEATURE_NAMES if PROC_FS + select SRCU config INSTRUCTION_DECODER def_bool y
arch/x86/kvm/Kconfig +1 -0
@@ -40,6 +40,7 @@ config KVM select HAVE_KVM_MSI select HAVE_KVM_CPU_RELAX_INTERCEPT select KVM_VFIO + select SRCU ---help--- Support hosting fully virtualized guest machines using hardware virtualization extensions. You will need a fairly recent
drivers/clk/Kconfig +1 -0
@@ -13,6 +13,7 @@ config COMMON_CLK bool select HAVE_CLK_PREPARE select CLKDEV_LOOKUP + select SRCU ---help--- The common clock framework is a single definition of struct clk, useful across many platforms, as well as an
drivers/cpufreq/Kconfig +1 -0
@@ -2,6 +2,7 @@ menu "CPU Frequency scaling" config CPU_FREQ bool "CPU Frequency scaling" + select SRCU help CPU Frequency scaling allows you to change the clock speed of CPUs on the fly. This is a nice method to save power, because
drivers/devfreq/Kconfig +1 -0
@@ -1,5 +1,6 @@ menuconfig PM_DEVFREQ bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support" + select SRCU help A device may have a list of frequencies and voltages available. devfreq, a generic DVFS framework can be registered for a device
drivers/md/Kconfig +1 -0
@@ -5,6 +5,7 @@ menuconfig MD bool "Multiple devices driver support (RAID and LVM)" depends on BLOCK + select SRCU help Support multiple physical spindles through a single logical device. Required for RAID and logical volume management.
drivers/net/Kconfig +1 -0
@@ -197,6 +197,7 @@ config NETCONSOLE_DYNAMIC config NETPOLL def_bool NETCONSOLE + select SRCU config NET_POLL_CONTROLLER def_bool NETPOLL
fs/btrfs/Kconfig +1 -0
@@ -8,6 +8,7 @@ config BTRFS_FS select LZO_DECOMPRESS select RAID6_PQ select XOR_BLOCKS + select SRCU help Btrfs is a general purpose copy-on-write filesystem with extents,
fs/notify/Kconfig +1 -0
@@ -1,5 +1,6 @@ config FSNOTIFY def_bool n + select SRCU source "fs/notify/dnotify/Kconfig" source "fs/notify/inotify/Kconfig"
fs/quota/Kconfig +1 -0
@@ -5,6 +5,7 @@ config QUOTA bool "Quota support" select QUOTACTL + select SRCU help If you say Y here, you will be able to set per user limits for disk usage (also called disk quotas). Currently, it works for the
init/Kconfig +9 -0
@@ -501,9 +501,17 @@ config TINY_RCU endchoice +config SRCU + bool + help + This option selects the sleepable version of RCU. This version + permits arbitrary sleeping or blocking within RCU read-side critical + sections. + config TASKS_RCU bool "Task_based RCU implementation using voluntary context switch" default n + select SRCU help This option enables a task-based RCU implementation that uses only voluntary context switch (not preemption!), idle, and
@@ -1595,6 +1603,7 @@ config PERF_EVENTS depends on HAVE_PERF_EVENTS select ANON_INODES select IRQ_WORK + select SRCU help Enable kernel support for various performance events provided by software and hardware.
kernel/notifier.c +3 -0
@@ -402,6 +402,7 @@ int raw_notifier_call_chain(struct raw_notifier_head *nh, }EXPORT_SYMBOL_GPL (raw_notifier_call_chain); +#ifdef CONFIG_SRCU /* * SRCU notifier chain routines. Registration and unregistration * use a mutex, and call_chain is synchronized by SRCU (no locks).
@@ -528,6 +529,8 @@ void srcu_init_notifier_head(struct srcu_notifier_head *nh) }EXPORT_SYMBOL_GPL (srcu_init_notifier_head); +#endif /* CONFIG_SRCU */ +static ATOMIC_NOTIFIER_HEAD (die_chain); int notrace notify_die(enum die_val val, const char *str,
kernel/power/Kconfig +1 -0
@@ -251,6 +251,7 @@ config APM_EMULATION config PM_OPP bool + select SRCU ---help--- SOCs have a standard set of tuples consisting of frequency and voltage pairs that the device will support per voltage domain. This
kernel/rcu/Makefile +2 -1
@@ -1,4 +1,5 @@ -obj-y += update.o srcu.o +obj-y += update.o +obj-$(CONFIG_SRCU) += srcu.o obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o obj-$(CONFIG_TREE_RCU) += tree.o obj-$(CONFIG_PREEMPT_RCU) += tree.o
lib/Kconfig.debug +1 -0
@@ -1215,6 +1215,7 @@ config RCU_TORTURE_TEST tristate "torture tests for RCU" depends on DEBUG_KERNEL select TORTURE_TEST + select SRCU default n help This option provides a kernel module that runs torture tests
mm/Kconfig +1 -0
@@ -325,6 +325,7 @@ config VIRT_TO_BUS config MMU_NOTIFIER bool + select SRCU config KSM bool "Enable KSM for page merging"
security/tomoyo/Kconfig +1 -0
@@ -5,6 +5,7 @@ config SECURITY_TOMOYO select SECURITYFS select SECURITY_PATH select SECURITY_NETWORK + select SRCU default n help This selects TOMOYO Linux, pathname-based access control.
Signature · 1 line
1.8.1.5
PATCH 2/3 rcu: Combine DEFINE_SRCU() and DEFINE_STATIC_SRCU()
In reply to Paul E. McKenneyFrom: "Paul E. McKenney" <[email protected]>
The DEFINE_SRCU() and DEFINE_STATIC_SRCU() definitions are quite similar, so this commit combines them, saving a bit of code and removing redundancy.
Signed-off-by Paul E. McKenney <[email protected]>
--- include/linux/srcu.h | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
include/linux/srcu.h +4 -6
@@ -102,13 +102,11 @@ void process_srcu(struct work_struct *work);* define and init a srcu struct at build time. * dont't call init_srcu_struct() nor cleanup_srcu_struct() on it. */ -#define DEFINE_SRCU (name) \ +#define __DEFINE_SRCU (name, is_static) \ static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\ - struct srcu_struct name = __SRCU_STRUCT_INIT(name); - -#define DEFINE_STATIC_SRCU (name) \ - static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\ - static struct srcu_struct name = __SRCU_STRUCT_INIT(name); + is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name) +#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */) +#define DEFINE_STATIC_SRCU (name) __DEFINE_SRCU(name, static)/** * call_srcu() - Queue a callback for invocation after an SRCU grace period
Signature · 1 line
1.8.1.5