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linux/arch/mips/kernel
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Huacai Chen db0dbd57d5 MIPS: sync-r4k: reduce skew while synchronization 
While synchronization, count register will go backwards for the master.
If synchronise_count_master() runs before synchronise_count_slave(),
skew becomes even more. The skew is very harmful for CPU hotplug (CPU0
do synchronization with CPU1, then CPU0 do synchronization with CPU2
and CPU0's count goes backwards, so it will be out of sync with CPU1).

After the commit cf9bfe55f2 (MIPS: Synchronize MIPS count one
CPU at a time), we needn't evaluate count_reference at the beginning of
synchronise_count_master() any more. Thus, we evaluate the initcount (It
seems like count_reference is redundant) in the 2nd loop. Since we write
the count register in the last loop, we don't need additional barriers
(the existing memory barriers are enough).

Moreover, I think we loop 3 times is enough to get a primed instruction
cache, this can also get less skew than looping 5 times.

Comments are also updated in this patch.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/12163/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-01-24 01:31:51 +01:00
..
.gitignore
8250-platform.c
asm-offsets.c MIPS: Set trap_no field in thread_struct on exception. 2015-09-03 12:08:04 +02:00
binfmt_elfn32.c
binfmt_elfo32.c
bmips_vec.S
branch.c MIPS: Fix branch emulation for BLTC and BGEC instructions 2015-07-09 11:10:40 +02:00
cevt-bcm1480.c MIPS: cevt-bcm1480: Migrate to new 'set-state' interface 2015-09-03 12:07:51 +02:00
cevt-ds1287.c MIPS: cevt-ds1287: Migrate to new 'set-state' interface 2015-09-03 12:07:51 +02:00
cevt-gt641xx.c MIPS: cevt-gt641xx: Migrate to new 'set-state' interface 2015-09-03 12:07:51 +02:00
cevt-r4k.c MIPS: cevt-r4k: Migrate to new 'set-state' interface 2015-09-03 12:07:52 +02:00
cevt-sb1250.c MIPS: cevt-sb1250: Migrate to new 'set-state' interface 2015-09-03 12:07:52 +02:00
cevt-txx9.c MIPS: cevt-txx9: Migrate to new 'set-state' interface 2015-09-03 12:07:53 +02:00
cps-vec-ns16550.S MIPS: CPS: Early debug using an ns16550-compatible UART 2015-11-11 08:34:25 +01:00
cps-vec.S MIPS: CPS: drop .set mips64r2 directives 2015-12-22 12:16:32 +01:00
cpu-bugs64.c
cpu-probe.c MIPS: Add IEEE Std 754 conformance mode selection 2016-01-20 00:39:20 +01:00
crash_dump.c
crash.c
csrc-bcm1480.c
csrc-ioasic.c
csrc-r4k.c MIPS: VDSO: Add implementations of gettimeofday() and clock_gettime() 2015-11-11 08:36:41 +01:00
csrc-sb1250.c
early_printk_8250.c
early_printk.c
elf.c MIPS: Add IEEE Std 754 conformance mode selection 2016-01-20 00:39:20 +01:00
entry.S
ftrace.c
genex.S MIPS: Fix LLVM build issue. 2015-08-18 11:40:20 +02:00
gpio_txx9.c
head.S MIPS: Add support for vmlinux.bin appended dtb 2015-06-21 21:54:14 +02:00
i8253.c
idle.c Merge branch '4.3-fixes' into mips-for-linux-next 2015-11-12 11:36:03 +01:00
irq_txx9.c
irq-gt641xx.c
irq-msc01.c
irq-rm7000.c
irq.c MIPS: IRQ/IP27: Move IRQ allocation API to platform code. 2015-06-21 21:54:31 +02:00
jump_label.c jump_label: Rename JUMP_LABEL_{EN,DIS}ABLE to JUMP_LABEL_{JMP,NOP} 2015-08-03 11:34:12 +02:00
kgdb.c MIPS: Get rid of 'kgdb_early_setup' cruft. 2015-06-21 21:54:10 +02:00
kprobes.c
linux32.c
machine_kexec.c
Makefile MIPS: CPS: Early debug using an ns16550-compatible UART 2015-11-11 08:34:25 +01:00
mcount.S
mips_ksyms.c MIPS: uaccess: Take EVA into account in [__]clear_user 2015-12-22 11:58:43 +01:00
mips_machine.c
mips-cm.c MIPS: CM, CPC: Ensure core-other GCRs reflect the correct core 2015-11-11 08:35:18 +01:00
mips-cpc.c MIPS: CM, CPC: Ensure core-other GCRs reflect the correct core 2015-11-11 08:35:18 +01:00
mips-mt-fpaff.c MIPS: Fix sched_getaffinity with MT FPAFF enabled 2015-08-03 09:25:02 +02:00
mips-mt.c
mips-r2-to-r6-emul.c MIPS: Declare mips_debugfs_dir in a header 2015-10-26 09:49:42 +01:00
module-rela.c
module.c
octeon_switch.S MIPS: Fix octeon FP context switch handling 2015-10-02 19:16:06 +02:00
perf_event_mipsxx.c MIPS: Add cases for CPU_I6400 2015-08-26 15:23:03 +02:00
perf_event.c
pm-cps.c MIPS: Add cases for CPU_I6400 2015-08-26 15:23:03 +02:00
pm.c
proc.c
process.c This is the final removal (after several years!) of the obsolete cpus_* 2015-04-20 10:19:03 -07:00
prom.c MIPS: Fix build with CONFIG_OF=y for non OF-enabled targets 2015-08-03 09:25:00 +02:00
ptrace32.c
ptrace.c MIPS: Add uprobes support. 2015-09-03 12:08:05 +02:00
r4k_fpu.S MIPS: Save MSA extended context around signals 2015-09-03 12:07:59 +02:00
r4k_switch.S MIPS: Tidy up FPU context switching 2015-09-03 12:08:05 +02:00
r2300_fpu.S
r2300_switch.S MIPS: Fix R2300 FP context switch handling 2015-10-02 19:16:46 +02:00
r6000_fpu.S
relocate_kernel.S MIPS: Replace add and sub instructions in relocate_kernel.S with addiu 2015-08-03 15:26:30 +02:00
reset.c
rtlx-cmp.c
rtlx-mt.c
rtlx.c
scall32-o32.S mips: add entry for new mlock2 syscall 2015-11-09 15:11:24 -08:00
scall64-64.S mips: add entry for new mlock2 syscall 2015-11-09 15:11:24 -08:00
scall64-n32.S mips: add entry for new mlock2 syscall 2015-11-09 15:11:24 -08:00
scall64-o32.S mips: add entry for new mlock2 syscall 2015-11-09 15:11:24 -08:00
segment.c MIPS: Declare mips_debugfs_dir in a header 2015-10-26 09:49:42 +01:00
setup.c MIPS: vmlinux: create a section for appended DTB 2015-11-12 11:35:48 +01:00
signal32.c MIPS: Initial implementation of a VDSO 2015-11-11 08:36:36 +01:00
signal_n32.c MIPS: Initial implementation of a VDSO 2015-11-11 08:36:36 +01:00
signal-common.h MIPS: Save MSA extended context around signals 2015-09-03 12:07:59 +02:00
signal.c MIPS: Initial implementation of a VDSO 2015-11-11 08:36:36 +01:00
smp-bmips.c MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
smp-cmp.c
smp-cps.c MIPS: CM: make use of mips_cm_{lock,unlock}_other 2015-11-11 08:35:17 +01:00
smp-gic.c MIPS: CM: make use of mips_cm_{lock,unlock}_other 2015-11-11 08:35:17 +01:00
smp-mt.c
smp-up.c
smp.c MIPS: Initialise MAARs on secondary CPUs 2015-09-27 14:15:26 +02:00
spinlock_test.c MIPS: Declare mips_debugfs_dir in a header 2015-10-26 09:49:42 +01:00
spram.c MIPS: Add cases for CPU_I6400 2015-08-26 15:23:03 +02:00
stacktrace.c MIPS: Add LATENCYTOP support 2015-11-11 08:36:46 +01:00
sync-r4k.c MIPS: sync-r4k: reduce skew while synchronization 2016-01-24 01:31:51 +01:00
syscall.c
sysrq.c MIPS: Refactor dumping of TLB registers for r3k/r4k 2015-09-03 12:07:45 +02:00
time.c
topology.c
traps.c Merge branch '4.3-fixes' into mips-for-linux-next 2015-11-12 11:36:03 +01:00
unaligned.c MIPS: Declare mips_debugfs_dir in a header 2015-10-26 09:49:42 +01:00
uprobes.c MIPS: Add uprobes support. 2015-09-03 12:08:05 +02:00
vdso.c MIPS: VDSO: Add implementations of gettimeofday() and clock_gettime() 2015-11-11 08:36:41 +01:00
vmlinux.lds.S Merge branch '4.3-fixes' into mips-for-linux-next 2015-11-12 11:36:03 +01:00
vpe-cmp.c
vpe-mt.c
vpe.c MIPS: MT: Remove "weak" from vpe_run() declaration 2015-08-26 15:23:40 +02:00
watch.c