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ae7eae9e03
linux/arch/arc/include/asm
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Vineet Gupta ae7eae9e03 ARC: LLOCK/SCOND based spin_lock 
Current spin_lock uses EXchange instruction to implement the atomic test
and set of lock location (reads orig value and ST 1). This however forces
the cacheline into exclusive state (because of the ST) and concurrent
loops in multiple cores will bounce the line around between cores.

Instead, use LLOCK/SCOND to implement the atomic test and set which is
better as line is in shared state while lock is spinning on LLOCK

The real motivation of this change however is to make way for future
changes in atomics to implement delayed retry (with backoff).
Initial experiment with delayed retry in atomics combined with orig
EX based spinlock was a total disaster (broke even LMBench) as
struct sock has a cache line sharing an atomic_t and spinlock. The
tight spinning on lock, caused the atomic retry to keep backing off
such that it would never finish.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-08-04 09:26:33 +05:30
..
arcregs.h ARCv2: Fix the peripheral address space detection 2015-08-03 19:34:07 +05:30
asm-offsets.h
atomic.h ARC: refactor atomic inline asm operands with symbolic names 2015-08-04 09:26:32 +05:30
barrier.h ARCv2: barriers 2015-06-25 06:00:17 +05:30
bitops.h ARC: Make ARC bitops "safer" (add anti-optimization) 2015-07-09 17:36:32 +05:30
bug.h ARC: BUG() dumps stack after @msg (@msg now same as in generic BUG)) 2014-10-13 14:46:18 +05:30
cache.h ARCv2: SLC: Handle explcit flush for DMA ops (w/o IO-coherency) 2015-06-25 06:00:19 +05:30
cacheflush.h ARC: fold ___flush_dcache_page into __flush_dcache_page 2015-05-19 11:27:13 +05:30
checksum.h ARC: Checksum/byteorder/swab routines 2013-02-11 20:00:34 +05:30
clk.h ARC: [DeviceTree] Convert some Kconfig items to runtime values 2013-02-15 23:15:56 +05:30
cmpxchg.h ARC: add smp barriers around atomics per Documentation/atomic_ops.txt 2015-06-25 06:00:16 +05:30
current.h ARC: remove extraneous __KERNEL__ guards 2014-10-13 14:46:20 +05:30
delay.h ARCv2: Adhere to Zero Delay loop restriction 2015-06-22 14:06:56 +05:30
disasm.h ARC: disassembly (needed by kprobes/kgdb/unaligned-access-emul) 2013-02-15 23:16:04 +05:30
dma-mapping.h Merge branch 'akpm' (patches from Andrew) 2015-07-01 17:47:51 -07:00
dma.h ARC: I/O and DMA Mappings 2013-02-15 23:15:54 +05:30
elf.h ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
entry-arcv2.h ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
entry-compact.h ARC: intc: split into ARCompact ISA specific, common bits 2015-06-19 18:09:40 +05:30
entry.h ARCv2: STAR 9000808988: signals involving Delay Slot 2015-06-22 14:06:55 +05:30
exec.h ARC: Fundamental ARCH data-types/defines 2013-02-11 20:00:34 +05:30
futex.h ARC: Add llock/scond to futex backend 2015-07-09 17:36:33 +05:30
io.h - Support for HS38 cores based on ARCv2 ISA 2015-07-01 09:24:26 -07:00
irq.h ARCv2: SMP: Support ARConnect (MCIP) for Inter-Core-Interrupts et al 2015-06-22 14:06:56 +05:30
irqflags-arcv2.h ARCv2: STAR 9000814690: Really Re-enable interrupts to avoid deadlocks 2015-06-22 14:06:55 +05:30
irqflags-compact.h ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
irqflags.h ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
Kbuild mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
kdebug.h ARC: Fundamental ARCH data-types/defines 2013-02-11 20:00:34 +05:30
kgdb.h ARC: Update order of registers in KGDB to match GDB 7.5 2014-10-13 14:46:20 +05:30
kprobes.h ARC: Remove explicit passing around of ECR 2013-06-26 15:30:50 +05:30
linkage.h ARC: switch to generic ENTRY/END assembler annotations 2014-03-26 14:31:28 +05:30
mach_desc.h arc: use common of_flat_dt_match_machine 2013-10-09 20:03:55 -05:00
mcip.h ARCv2: SMP: clocksource: Enable Global Real Time counter 2015-06-22 14:06:57 +05:30
mmu_context.h ARC: [SMP] TLB flush 2013-11-06 10:41:45 +05:30
mmu.h ARCv2: MMUv4: TLB programming Model changes 2015-06-22 14:06:55 +05:30
module.h ARC: DWARF2 .debug_frame based stack unwinder 2013-02-15 23:16:03 +05:30
mutex.h ARC: SMP support 2013-02-15 23:16:02 +05:30
page.h ARC: [mm] Make stack/heap Non-executable by default 2013-06-22 19:23:20 +05:30
perf_event.h ARC: perf: support cache hit/miss ratio 2015-04-20 18:27:34 +05:30
pgalloc.h arc: handle pgtable_page_ctor() fail 2013-11-15 09:32:16 +09:00
pgtable.h ARCv2: MMUv4: TLB programming Model changes 2015-06-22 14:06:55 +05:30
processor.h ARC: mm: document system mem map clearly 2015-06-19 18:09:29 +05:30
ptrace.h ARC: make sure instruction_pointer() returns unsigned value 2015-07-13 13:33:18 +05:30
sections.h of/fdt: consolidate built-in dtb section variables 2014-04-30 00:59:13 -05:00
segment.h ARC: uaccess friends 2013-02-11 20:00:31 +05:30
serial.h ARC: Dynamically determine BASE_BAUD from DeviceTree 2015-02-02 17:08:37 +05:30
setup.h ARC: RIP @running_on_hw 2014-10-13 14:46:17 +05:30
shmparam.h ARC: [mm] Aliasing VIPT dcache support 4/4 2013-05-09 22:00:57 +05:30
smp.h ARC: Allow SMP kernel to build/boot on UP-only infrastructure 2014-09-27 14:49:01 +05:30
spinlock_types.h ARC: Code cosmetics (Nothing semantical) 2013-08-29 17:51:15 +05:30
spinlock.h ARC: LLOCK/SCOND based spin_lock 2015-08-04 09:26:33 +05:30
stacktrace.h ARC: Make arc_unwind_core accessible externally 2015-02-27 10:15:00 +05:30
string.h ARC: remove extraneous __KERNEL__ guards 2014-10-13 14:46:20 +05:30
switch_to.h ARC: Process-creation/scheduling/idle-loop 2013-02-11 20:00:38 +05:30
syscall.h ARC: stop using pt_regs->orig_r8 2013-06-22 19:23:26 +05:30
syscalls.h ARC: remove extraneous __KERNEL__ guards 2014-10-13 14:46:20 +05:30
thread_info.h ARCv2: Support for ARCv2 ISA and HS38x cores 2015-06-22 14:06:55 +05:30
timex.h ARC: Timers/counters/delay management 2013-02-11 20:00:39 +05:30
tlb-mmu1.h ARC: Disintegrate arcregs.h 2013-06-22 13:46:42 +05:30
tlb.h ARC: Disintegrate arcregs.h 2013-06-22 13:46:42 +05:30
tlbflush.h ARC: [SMP] TLB flush 2013-11-06 10:41:45 +05:30
uaccess.h ARCv2: Adhere to Zero Delay loop restriction 2015-06-22 14:06:56 +05:30
unaligned.h ARC: rename kconfig option for unaligned emulation 2014-10-13 14:46:15 +05:30
unwind.h ARC: DWARF2 .debug_frame based stack unwinder 2013-02-15 23:16:03 +05:30