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linux/arch/mips/include/asm/spinlock.h

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Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 22:20:36 +00:00
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
[MIPS] Improve branch prediction in ll/sc atomic operations. Now that finally all supported versions of binutils have functioning support for .subsection use .subsection to tweak the branch prediction I did not modify the R10000 errata variants because it seems unclear if this will invalidate the workaround which actually relies on the cheesy prediction of branch likely to cause a misspredict if the sc was successful. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-09-28 00:45:21 +00:00
* Copyright (C) 1999, 2000, 06 Ralf Baechle (ralf@linux-mips.org)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 22:20:36 +00:00
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
*/
#ifndef _ASM_SPINLOCK_H
#define _ASM_SPINLOCK_H
locking/spinlock, arch: Update and fix spin_unlock_wait() implementations This patch updates/fixes all spin_unlock_wait() implementations. The update is in semantics; where it previously was only a control dependency, we now upgrade to a full load-acquire to match the store-release from the spin_unlock() we waited on. This ensures that when spin_unlock_wait() returns, we're guaranteed to observe the full critical section we waited on. This fixes a number of spin_unlock_wait() users that (not unreasonably) rely on this. I also fixed a number of ticket lock versions to only wait on the current lock holder, instead of for a full unlock, as this is sufficient. Furthermore; again for ticket locks; I added an smp_rmb() in between the initial ticket load and the spin loop testing the current value because I could not convince myself the address dependency is sufficient, esp. if the loads are of different sizes. I'm more than happy to remove this smp_rmb() again if people are certain the address dependency does indeed work as expected. Note: PPC32 will be fixed independently Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: chris@zankel.net Cc: cmetcalf@mellanox.com Cc: davem@davemloft.net Cc: dhowells@redhat.com Cc: james.hogan@imgtec.com Cc: jejb@parisc-linux.org Cc: linux@armlinux.org.uk Cc: mpe@ellerman.id.au Cc: ralf@linux-mips.org Cc: realmz6@gmail.com Cc: rkuo@codeaurora.org Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Cc: vgupta@synopsys.com Cc: ysato@users.sourceforge.jp Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-26 08:35:03 +00:00
#include <asm/processor.h>
MIPS: Use queued read/write locks (qrwlock) This patch switches MIPS to make use of generically implemented queued read/write locks, rather than the custom implementation used previously. This allows us to drop a whole load of inline assembly, share more generic code, and is also a performance win. Results from running the AIM7 short workload on a MIPS Creator Ci40 (ie. 2 core 2 thread interAptiv CPU clocked at 546MHz) with v4.12-rc4 pistachio_defconfig, with ftrace disabled due to a current bug, and both with & without use of queued rwlocks & spinlocks: Forks | v4.12-rc4 | +qlocks | Change -------|-----------|----------|-------- 10 | 52630.32 | 53316.31 | +1.01% 20 | 51777.80 | 52623.15 | +1.02% 30 | 51645.92 | 52517.26 | +1.02% 40 | 51634.88 | 52419.89 | +1.02% 50 | 51506.75 | 52307.81 | +1.02% 60 | 51500.74 | 52322.72 | +1.02% 70 | 51434.81 | 52288.60 | +1.02% 80 | 51423.22 | 52434.85 | +1.02% 90 | 51428.65 | 52410.10 | +1.02% The kernels used for these tests also had my "MIPS: Hardcode cpu_has_* where known at compile time due to ISA" patch applied, which allows the kernel_uses_llsc checks in cmpxchg() & xchg() to be optimised away at compile time. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16357/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-06-10 00:26:42 +00:00
#include <asm/qrwlock.h>
MIPS: Use queued spinlocks (qspinlock) This patch switches MIPS to make use of generically implemented queued spinlocks, rather than the ticket spinlocks used previously. This allows us to drop a whole load of inline assembly, share more generic code, and is also a performance win. Results from running the AIM7 short workload on a MIPS Creator Ci40 (ie. 2 core 2 thread interAptiv CPU clocked at 546MHz) with v4.12-rc4 pistachio_defconfig, with ftrace disabled due to a current bug, and both with & without use of queued rwlocks & spinlocks: Forks | v4.12-rc4 | +qlocks | Change -------|-----------|----------|-------- 10 | 52630.32 | 53316.31 | +1.01% 20 | 51777.80 | 52623.15 | +1.02% 30 | 51645.92 | 52517.26 | +1.02% 40 | 51634.88 | 52419.89 | +1.02% 50 | 51506.75 | 52307.81 | +1.02% 60 | 51500.74 | 52322.72 | +1.02% 70 | 51434.81 | 52288.60 | +1.02% 80 | 51423.22 | 52434.85 | +1.02% 90 | 51428.65 | 52410.10 | +1.02% The kernels used for these tests also had my "MIPS: Hardcode cpu_has_* where known at compile time due to ISA" patch applied, which allows the kernel_uses_llsc checks in cmpxchg() & xchg() to be optimised away at compile time. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16358/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-06-10 00:26:43 +00:00
#include <asm/qspinlock.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 22:20:36 +00:00
locking: Convert raw_rwlock functions to arch_rwlock Name space cleanup for rwlock functions. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org
2009-12-03 19:08:46 +00:00
#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
[MIPS] Replace generic__raw_read_trylock usage generic__raw_read_trylock() is a defect generic function actually doing a __raw_read_lock ... Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-08-31 13:16:06 +00:00
locking: Convert __raw_spin* functions to arch_spin* Name space cleanup. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org
2009-12-02 19:01:25 +00:00
#define arch_spin_relax(lock) cpu_relax()
#define arch_read_relax(lock) cpu_relax()
#define arch_write_relax(lock) cpu_relax()
[PATCH] Directed yield: cpu_relax variants for spinlocks and rw-locks On systems running with virtual cpus there is optimization potential in regard to spinlocks and rw-locks. If the virtual cpu that has taken a lock is known to a cpu that wants to acquire the same lock it is beneficial to yield the timeslice of the virtual cpu in favour of the cpu that has the lock (directed yield). With CONFIG_PREEMPT="n" this can be implemented by the architecture without common code changes. Powerpc already does this. With CONFIG_PREEMPT="y" the lock loops are coded with _raw_spin_trylock, _raw_read_trylock and _raw_write_trylock in kernel/spinlock.c. If the lock could not be taken cpu_relax is called. A directed yield is not possible because cpu_relax doesn't know anything about the lock. To be able to yield the lock in favour of the current lock holder variants of cpu_relax for spinlocks and rw-locks are needed. The new _raw_spin_relax, _raw_read_relax and _raw_write_relax primitives differ from cpu_relax insofar that they have an argument: a pointer to the lock structure. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 06:27:43 +00:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 22:20:36 +00:00
#endif /* _ASM_SPINLOCK_H */
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