linux/kernel/Kconfig.locks

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# SPDX-License-Identifier: GPL-2.0-only
#
# The ARCH_INLINE foo is necessary because select ignores "depends on"
#
config ARCH_INLINE_SPIN_TRYLOCK
bool
config ARCH_INLINE_SPIN_TRYLOCK_BH
bool
config ARCH_INLINE_SPIN_LOCK
bool
config ARCH_INLINE_SPIN_LOCK_BH
bool
config ARCH_INLINE_SPIN_LOCK_IRQ
bool
config ARCH_INLINE_SPIN_LOCK_IRQSAVE
bool
config ARCH_INLINE_SPIN_UNLOCK
bool
config ARCH_INLINE_SPIN_UNLOCK_BH
bool
config ARCH_INLINE_SPIN_UNLOCK_IRQ
bool
config ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
bool
config ARCH_INLINE_READ_TRYLOCK
bool
config ARCH_INLINE_READ_LOCK
bool
config ARCH_INLINE_READ_LOCK_BH
bool
config ARCH_INLINE_READ_LOCK_IRQ
bool
config ARCH_INLINE_READ_LOCK_IRQSAVE
bool
config ARCH_INLINE_READ_UNLOCK
bool
config ARCH_INLINE_READ_UNLOCK_BH
bool
config ARCH_INLINE_READ_UNLOCK_IRQ
bool
config ARCH_INLINE_READ_UNLOCK_IRQRESTORE
bool
config ARCH_INLINE_WRITE_TRYLOCK
bool
config ARCH_INLINE_WRITE_LOCK
bool
config ARCH_INLINE_WRITE_LOCK_BH
bool
config ARCH_INLINE_WRITE_LOCK_IRQ
bool
config ARCH_INLINE_WRITE_LOCK_IRQSAVE
bool
config ARCH_INLINE_WRITE_UNLOCK
bool
config ARCH_INLINE_WRITE_UNLOCK_BH
bool
config ARCH_INLINE_WRITE_UNLOCK_IRQ
bool
config ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
bool
config UNINLINE_SPIN_UNLOCK
bool
#
# lock_* functions are inlined when:
# - DEBUG_SPINLOCK=n and GENERIC_LOCKBREAK=n and ARCH_INLINE_*LOCK=y
#
# trylock_* functions are inlined when:
# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
#
# unlock and unlock_irq functions are inlined when:
# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
# or
# - DEBUG_SPINLOCK=n and PREEMPTION=n
#
# unlock_bh and unlock_irqrestore functions are inlined when:
# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
#
if !DEBUG_SPINLOCK
config INLINE_SPIN_TRYLOCK
def_bool y
depends on ARCH_INLINE_SPIN_TRYLOCK
config INLINE_SPIN_TRYLOCK_BH
def_bool y
depends on ARCH_INLINE_SPIN_TRYLOCK_BH
config INLINE_SPIN_LOCK
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK
config INLINE_SPIN_LOCK_BH
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_BH
config INLINE_SPIN_LOCK_IRQ
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQ
config INLINE_SPIN_LOCK_IRQSAVE
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQSAVE
config INLINE_SPIN_UNLOCK_BH
def_bool y
depends on ARCH_INLINE_SPIN_UNLOCK_BH
config INLINE_SPIN_UNLOCK_IRQ
def_bool y
depends on !PREEMPTION || ARCH_INLINE_SPIN_UNLOCK_IRQ
config INLINE_SPIN_UNLOCK_IRQRESTORE
def_bool y
depends on ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
config INLINE_READ_TRYLOCK
def_bool y
depends on ARCH_INLINE_READ_TRYLOCK
config INLINE_READ_LOCK
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK
config INLINE_READ_LOCK_BH
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_BH
config INLINE_READ_LOCK_IRQ
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQ
config INLINE_READ_LOCK_IRQSAVE
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQSAVE
config INLINE_READ_UNLOCK
def_bool y
depends on !PREEMPTION || ARCH_INLINE_READ_UNLOCK
config INLINE_READ_UNLOCK_BH
def_bool y
depends on ARCH_INLINE_READ_UNLOCK_BH
config INLINE_READ_UNLOCK_IRQ
def_bool y
depends on !PREEMPTION || ARCH_INLINE_READ_UNLOCK_IRQ
config INLINE_READ_UNLOCK_IRQRESTORE
def_bool y
depends on ARCH_INLINE_READ_UNLOCK_IRQRESTORE
config INLINE_WRITE_TRYLOCK
def_bool y
depends on ARCH_INLINE_WRITE_TRYLOCK
config INLINE_WRITE_LOCK
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK
config INLINE_WRITE_LOCK_BH
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_BH
config INLINE_WRITE_LOCK_IRQ
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQ
config INLINE_WRITE_LOCK_IRQSAVE
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQSAVE
config INLINE_WRITE_UNLOCK
def_bool y
depends on !PREEMPTION || ARCH_INLINE_WRITE_UNLOCK
config INLINE_WRITE_UNLOCK_BH
def_bool y
depends on ARCH_INLINE_WRITE_UNLOCK_BH
config INLINE_WRITE_UNLOCK_IRQ
def_bool y
depends on !PREEMPTION || ARCH_INLINE_WRITE_UNLOCK_IRQ
config INLINE_WRITE_UNLOCK_IRQRESTORE
def_bool y
depends on ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
endif
config ARCH_SUPPORTS_ATOMIC_RMW
bool
config MUTEX_SPIN_ON_OWNER
def_bool y
depends on SMP && ARCH_SUPPORTS_ATOMIC_RMW
config RWSEM_SPIN_ON_OWNER
def_bool y
locking/rwsem: Remove rwsem-spinlock.c & use rwsem-xadd.c for all archs Currently, we have two different implementation of rwsem: 1) CONFIG_RWSEM_GENERIC_SPINLOCK (rwsem-spinlock.c) 2) CONFIG_RWSEM_XCHGADD_ALGORITHM (rwsem-xadd.c) As we are going to use a single generic implementation for rwsem-xadd.c and no architecture-specific code will be needed, there is no point in keeping two different implementations of rwsem. In most cases, the performance of rwsem-spinlock.c will be worse. It also doesn't get all the performance tuning and optimizations that had been implemented in rwsem-xadd.c over the years. For simplication, we are going to remove rwsem-spinlock.c and make all architectures use a single implementation of rwsem - rwsem-xadd.c. All references to RWSEM_GENERIC_SPINLOCK and RWSEM_XCHGADD_ALGORITHM in the code are removed. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-riscv@lists.infradead.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Cc: linuxppc-dev@lists.ozlabs.org Cc: nios2-dev@lists.rocketboards.org Cc: openrisc@lists.librecores.org Cc: uclinux-h8-devel@lists.sourceforge.jp Link: https://lkml.kernel.org/r/20190322143008.21313-3-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-03-22 14:30:07 +00:00
depends on SMP && ARCH_SUPPORTS_ATOMIC_RMW
config LOCK_SPIN_ON_OWNER
def_bool y
depends on MUTEX_SPIN_ON_OWNER || RWSEM_SPIN_ON_OWNER
config ARCH_USE_QUEUED_SPINLOCKS
locking/qspinlock: Introduce a simple generic 4-byte queued spinlock This patch introduces a new generic queued spinlock implementation that can serve as an alternative to the default ticket spinlock. Compared with the ticket spinlock, this queued spinlock should be almost as fair as the ticket spinlock. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. Only in light to moderate contention where the average queue depth is around 1-3 will this queued spinlock be potentially a bit slower due to the higher slowpath overhead. This queued spinlock is especially suit to NUMA machines with a large number of cores as the chance of spinlock contention is much higher in those machines. The cost of contention is also higher because of slower inter-node memory traffic. Due to the fact that spinlocks are acquired with preemption disabled, the process will not be migrated to another CPU while it is trying to get a spinlock. Ignoring interrupt handling, a CPU can only be contending in one spinlock at any one time. Counting soft IRQ, hard IRQ and NMI, a CPU can only have a maximum of 4 concurrent lock waiting activities. By allocating a set of per-cpu queue nodes and used them to form a waiting queue, we can encode the queue node address into a much smaller 24-bit size (including CPU number and queue node index) leaving one byte for the lock. Please note that the queue node is only needed when waiting for the lock. Once the lock is acquired, the queue node can be released to be used later. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Daniel J Blueman <daniel@numascale.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Douglas Hatch <doug.hatch@hp.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paolo Bonzini <paolo.bonzini@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Scott J Norton <scott.norton@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1429901803-29771-2-git-send-email-Waiman.Long@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-24 18:56:30 +00:00
bool
config QUEUED_SPINLOCKS
def_bool y if ARCH_USE_QUEUED_SPINLOCKS
depends on SMP
locking/qspinlock: Introduce a simple generic 4-byte queued spinlock This patch introduces a new generic queued spinlock implementation that can serve as an alternative to the default ticket spinlock. Compared with the ticket spinlock, this queued spinlock should be almost as fair as the ticket spinlock. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. Only in light to moderate contention where the average queue depth is around 1-3 will this queued spinlock be potentially a bit slower due to the higher slowpath overhead. This queued spinlock is especially suit to NUMA machines with a large number of cores as the chance of spinlock contention is much higher in those machines. The cost of contention is also higher because of slower inter-node memory traffic. Due to the fact that spinlocks are acquired with preemption disabled, the process will not be migrated to another CPU while it is trying to get a spinlock. Ignoring interrupt handling, a CPU can only be contending in one spinlock at any one time. Counting soft IRQ, hard IRQ and NMI, a CPU can only have a maximum of 4 concurrent lock waiting activities. By allocating a set of per-cpu queue nodes and used them to form a waiting queue, we can encode the queue node address into a much smaller 24-bit size (including CPU number and queue node index) leaving one byte for the lock. Please note that the queue node is only needed when waiting for the lock. Once the lock is acquired, the queue node can be released to be used later. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Daniel J Blueman <daniel@numascale.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Douglas Hatch <doug.hatch@hp.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paolo Bonzini <paolo.bonzini@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Scott J Norton <scott.norton@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1429901803-29771-2-git-send-email-Waiman.Long@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-24 18:56:30 +00:00
bpf: introduce bpf_spin_lock Introduce 'struct bpf_spin_lock' and bpf_spin_lock/unlock() helpers to let bpf program serialize access to other variables. Example: struct hash_elem { int cnt; struct bpf_spin_lock lock; }; struct hash_elem * val = bpf_map_lookup_elem(&hash_map, &key); if (val) { bpf_spin_lock(&val->lock); val->cnt++; bpf_spin_unlock(&val->lock); } Restrictions and safety checks: - bpf_spin_lock is only allowed inside HASH and ARRAY maps. - BTF description of the map is mandatory for safety analysis. - bpf program can take one bpf_spin_lock at a time, since two or more can cause dead locks. - only one 'struct bpf_spin_lock' is allowed per map element. It drastically simplifies implementation yet allows bpf program to use any number of bpf_spin_locks. - when bpf_spin_lock is taken the calls (either bpf2bpf or helpers) are not allowed. - bpf program must bpf_spin_unlock() before return. - bpf program can access 'struct bpf_spin_lock' only via bpf_spin_lock()/bpf_spin_unlock() helpers. - load/store into 'struct bpf_spin_lock lock;' field is not allowed. - to use bpf_spin_lock() helper the BTF description of map value must be a struct and have 'struct bpf_spin_lock anyname;' field at the top level. Nested lock inside another struct is not allowed. - syscall map_lookup doesn't copy bpf_spin_lock field to user space. - syscall map_update and program map_update do not update bpf_spin_lock field. - bpf_spin_lock cannot be on the stack or inside networking packet. bpf_spin_lock can only be inside HASH or ARRAY map value. - bpf_spin_lock is available to root only and to all program types. - bpf_spin_lock is not allowed in inner maps of map-in-map. - ld_abs is not allowed inside spin_lock-ed region. - tracing progs and socket filter progs cannot use bpf_spin_lock due to insufficient preemption checks Implementation details: - cgroup-bpf class of programs can nest with xdp/tc programs. Hence bpf_spin_lock is equivalent to spin_lock_irqsave. Other solutions to avoid nested bpf_spin_lock are possible. Like making sure that all networking progs run with softirq disabled. spin_lock_irqsave is the simplest and doesn't add overhead to the programs that don't use it. - arch_spinlock_t is used when its implemented as queued_spin_lock - archs can force their own arch_spinlock_t - on architectures where queued_spin_lock is not available and sizeof(arch_spinlock_t) != sizeof(__u32) trivial lock is used. - presence of bpf_spin_lock inside map value could have been indicated via extra flag during map_create, but specifying it via BTF is cleaner. It provides introspection for map key/value and reduces user mistakes. Next steps: - allow bpf_spin_lock in other map types (like cgroup local storage) - introduce BPF_F_LOCK flag for bpf_map_update() syscall and helper to request kernel to grab bpf_spin_lock before rewriting the value. That will serialize access to map elements. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-31 23:40:04 +00:00
config BPF_ARCH_SPINLOCK
bool
config ARCH_USE_QUEUED_RWLOCKS
bool
config QUEUED_RWLOCKS
def_bool y if ARCH_USE_QUEUED_RWLOCKS
depends on SMP && !PREEMPT_RT
config ARCH_HAS_MMIOWB
bool
config MMIOWB
def_bool y if ARCH_HAS_MMIOWB
depends on SMP