linux-toradex.git/arch/s390/kernel/vtime.c, branch v6.7

cputime: remove cputime_to_nsecs fallback

2022-12-27T11:52:17+00:00

The archs that use cputime_to_nsecs() internally provide their own
definition and don't need the fallback. cputime_to_usecs() unused except
in this fallback, and is not defined anywhere.

This removes the final remnant of the cputime_t code from the kernel.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Alexander Gordeev 
Link: https://lore.kernel.org/r/20221220070705.2958959-1-npiggin@gmail.com

s390: assume stckf is always present

2022-03-10T14:58:17+00:00

With z10 as minimum supported machine generation the store-clock-fast
facility (25) is always present and checked in als code.
Drop alternatives and always use stckf.

Acked-by: Ilya Leoshkevich 
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/vtime: fix increased steal time accounting

2021-03-15T18:09:25+00:00

Commit 152e9b8676c6e ("s390/vtime: steal time exponential moving average")
inadvertently changed the input value for account_steal_time() from
"cputime_to_nsecs(steal)" to just "steal", resulting in broken increased
steal time accounting.

Fix this by changing it back to "cputime_to_nsecs(steal)".

Fixes: 152e9b8676c6e ("s390/vtime: steal time exponential moving average")
Cc:  # 5.1
Reported-by: Sabine Forkel 
Reviewed-by: Heiko Carstens 
Signed-off-by: Gerald Schaefer 
Signed-off-by: Heiko Carstens

s390/vtime: use cpu alternative for stck/stckf

2021-02-09T14:57:06+00:00

Use a cpu alternative to switch between stck and stckf instead of
making it compile time dependent. This will also make kernels compiled
for old machines, but running on newer machines, use stckf.

Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/vtime: fix inline assembly clobber list

2021-02-09T14:57:05+00:00

The stck/stckf instruction used within the inline assembly within
do_account_vtime() changes the condition code. This is not reflected
with the clobber list, and therefore might result in incorrect code
generation.

It seems unlikely that the compiler could generate incorrect code
considering the surrounding C code, but it must still be fixed.

Cc: 
Reviewed-by: Christian Borntraeger 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

sched/vtime: Consolidate IRQ time accounting

2020-12-02T19:20:05+00:00

The 3 architectures implementing CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
all have their own version of irq time accounting that dispatch the
cputime to the appropriate index: hardirq, softirq, system, idle,
guest... from an all-in-one function.

Instead of having these ad-hoc versions, move the cputime destination
dispatch decision to the core code and leave only the actual per-index
cputime accounting to the architecture.

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20201202115732.27827-4-frederic@kernel.org

s390/vtime: Use the generic IRQ entry accounting

2020-12-02T19:20:04+00:00

s390 has its own version of IRQ entry accounting because it doesn't
account the idle time the same way the other architectures do. Only
the actual idle sleep time is accounted as idle time, the rest of the
idle task execution is accounted as system time.

Make the generic IRQ entry accounting aware of architectures that have
their own way of accounting idle time and convert s390 to use it.

This prepares s390 to get involved in further consolidations of IRQ
time accounting.

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20201202115732.27827-3-frederic@kernel.org

sched/cputime: Remove symbol exports from IRQ time accounting

2020-12-02T19:20:04+00:00

account_irq_enter_time() and account_irq_exit_time() are not called
from modules. EXPORT_SYMBOL_GPL() can be safely removed from the IRQ
cputime accounting functions called from there.

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20201202115732.27827-2-frederic@kernel.org

sched/cputime: Rename vtime_account_system() to vtime_account_kernel()

2019-10-09T10:39:25+00:00

vtime_account_system() decides if we need to account the time to the
system (__vtime_account_system()) or to the guest (vtime_account_guest()).

So this function is a misnomer as we are on a higher level than
"system". All we know when we call that function is that we are
accounting kernel cputime. Whether it belongs to guest or system time
is a lower level detail.

Rename this function to vtime_account_kernel(). This will clarify things
and avoid too many underscored vtime_account_system() versions.

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Cc: Wanpeng Li 
Cc: Yauheni Kaliuta 
Link: https://lkml.kernel.org/r/20191003161745.28464-2-frederic@kernel.org
Signed-off-by: Ingo Molnar

s390: correct some inline assembly constraints

2019-04-17T08:40:57+00:00

Inline assembly code changed in this patch should really use "Q"
constraint "Memory reference without index register and with short
displacement". The kernel build with kasan instrumentation enabled
might occasionally break otherwise (due to stack instrumentation).

Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky