From: Guo Ren
We don't have native hw xchg16 instruction, so let qspinlock
generic code to deal with it.
Using the full-word atomic xchg instructions implement xchg16 has
the semantic risk for atomic operations.
This patch cancels the dependency of on qspinlock generic code on
architecture's xc
From: Guo Ren
We don't have native hw xchg16 instruction, so let qspinlock
generic code to deal with it.
Using the full-word atomic xchg instructions implement xchg16 has
the semantic risk for atomic operations.
This patch cancels the dependency of on qspinlock generic code on
architecture's xc
From: Guo Ren
We don't have native hw xchg16 instruction, so let qspinlock
generic code to deal with it.
Using the full-word atomic xchg instructions implement xchg16 has
the semantic risk for atomic operations.
This patch cancels the dependency of on qspinlock generic code on
architecture's xc
From: Guo Ren
We don't have native hw xchg16 instruction, so let qspinlock
generic code to deal with it.
Using the full-word atomic xchg instructions implement xchg16 has
the semantic risk for atomic operations.
This patch cancels the dependency of on qspinlock generic code on
architecture's xc
From: Guo Ren
Update the C-SKY port to use the generic qspinlock and qrwlock.
C-SKY only support ldex.w/stex.w with word(double word) size &
align access. So it must select XCHG32 to let qspinlock only use
word atomic xchg_tail.
Signed-off-by: Guo Ren
Cc: Waiman Long
Cc: Peter Zijlstra
Cc: W
From: Michael Clark
Update the RISC-V port to use the generic qspinlock and qrwlock.
This patch requires support for xchg_xtail for full-word which
are added by a previous patch:
Guo added select ARCH_USE_QUEUED_SPINLOCKS_XCHG32 in Kconfig
Guo fixed up compile error which made by below include
From: Guo Ren
Some architectures don't have sub-word swap atomic instruction,
they only have the full word's one.
The sub-word swap only improve the performance when:
NR_CPUS < 16K
* 0- 7: locked byte
* 8: pending
* 9-15: not used
* 16-17: tail index
* 18-31: tail cpu (+1)
The 9-15 b
From: Guo Ren
Current riscv is still using baby spinlock implementation. It'll cause
fairness and cache line bouncing problems. Many people are involved
and pay the efforts to improve it:
- The first version of patch was made in 2019.1:
https://lore.kernel.org/linux-riscv/20190211043829.300
Hi Christophe,
On 3/27/21 5:19 PM, Christophe Leroy wrote:
[..]
>> I opportunistically Cc stable on it: I understand that usually such
>> stuff isn't a stable material, but that will allow us in CRIU have
>> one workaround less that is needed just for one release (v5.11) on
>> one platform (ppc64)
When compiling the powerpc with the SMP disabled, it shows the issue:
arch/powerpc/kernel/watchdog.c: In function ‘watchdog_smp_panic’:
arch/powerpc/kernel/watchdog.c:177:4: error: implicit declaration of function
‘smp_send_nmi_ipi’; did you mean ‘smp_send_stop’?
[-Werror=implicit-function-decla
On 3/26/21 5:38 PM, Christoph Hellwig wrote:
> Just call compat_do_execve instead.
compat_do_execveat(), maybe?
> Signed-off-by: Christoph Hellwig
> ---
> fs/exec.c | 17 +
> 1 file changed, 1 insertion(+), 16 deletions(-)
>
> diff --git a/fs/exec.c b/fs/exec.c
> index b63f
Le 12/03/2021 à 13:50, Christophe Leroy a écrit :
This can be done in C, do it.
Unrolling the loop gains approx. 15% performance.
From now on, prepare_transfer_to_handler() is only for
interrupts from kernel.
Signed-off-by: Christophe Leroy
---
arch/powerpc/include/asm/book3s/32/kup.h |
Le 26/03/2021 à 20:17, Dmitry Safonov a écrit :
Since commit 511157ab641e ("powerpc/vdso: Move vdso datapage up front")
VVAR page is in front of the VDSO area. In result it breaks CRIU
(Checkpoint Restore In Userspace) [1], where CRIU expects that "[vdso]"
from /proc/../maps points at ELF/vdso
Arnaldo writes:
> On March 25, 2021 11:38:01 AM GMT-03:00, Peter Zijlstra
> wrote:
>>On Thu, Mar 25, 2021 at 10:01:35AM -0300, Arnaldo Carvalho de Melo
>>wrote:.
>>> > > Also for CPU_FTR_ARCH_31, capture the two cycle counter
>>information in
>>> > > two 16 bit fields of perf_sample_weight struc
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