Hi Kevin,
Your patchset was fine but I just did a second round. Namely I did the following changes:
* Drop the 64 bits dependency after we settle the new dependency on HAVE_VIRT_CPU_ACCOUNTING_GEN
and not before. This way we don't have a middle state that loose the dependency in the middle of
the patchset. Probablyt no big deal but it looks more natural this way.
* Refined a few changelogs.
If you're ok I'll send a pull request to Ingo.
Thanks.
Kevin Hilman (3):
vtime: Add HAVE_VIRT_CPU_ACCOUNTING_GEN Kconfig
nohz: Drop generic vtime obsolete dependency on CONFIG_64BIT
ARM: Kconfig: allow full nohz CPU accounting
arch/Kconfig | 12 ++++++++++++
arch/arm/Kconfig | 1 +
init/Kconfig | 3 ++-
kernel/time/Kconfig | 2 +-
4 files changed, 16 insertions(+), 2 deletions(-)
--
1.8.3.1
From: Kevin Hilman <[email protected]>
With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. In order
to use that feature, arch code should be audited to ensure there are no
races in concurrent read/write of cputime_t. For example,
reading/writing 64-bit cputime_t on some 32-bit arches may require
multiple accesses for low and high value parts, so proper locking
is needed to protect against concurrent accesses.
Therefore, add CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN which arches can
enable after they've been audited for potential races.
This option is automatically enabled on 64-bit platforms.
Feature requested by Frederic Weisbecker.
Signed-off-by: Kevin Hilman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Russell King <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Arm Linux <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
---
arch/Kconfig | 12 ++++++++++++
init/Kconfig | 1 +
kernel/time/Kconfig | 1 +
3 files changed, 14 insertions(+)
diff --git a/arch/Kconfig b/arch/Kconfig
index af2cc6e..185f8b0 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -353,6 +353,18 @@ config HAVE_CONTEXT_TRACKING
config HAVE_VIRT_CPU_ACCOUNTING
bool
+config HAVE_VIRT_CPU_ACCOUNTING_GEN
+ bool
+ default y if 64BIT
+ help
+ With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
+ Before enabling this option, arch code must be audited
+ to ensure there are no races in concurrent read/write of
+ cputime_t. For example, reading/writing 64-bit cputime_t on
+ some 32-bit arches may require multiple accesses, so proper
+ locking is needed to protect against concurrent accesses.
+
+
config HAVE_IRQ_TIME_ACCOUNTING
bool
help
diff --git a/init/Kconfig b/init/Kconfig
index 3ecd8a1..68c1a0e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -355,6 +355,7 @@ config VIRT_CPU_ACCOUNTING_NATIVE
config VIRT_CPU_ACCOUNTING_GEN
bool "Full dynticks CPU time accounting"
depends on HAVE_CONTEXT_TRACKING && 64BIT
+ depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
select VIRT_CPU_ACCOUNTING
select CONTEXT_TRACKING
help
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 2b62fe8..f148475 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -101,6 +101,7 @@ config NO_HZ_FULL
depends on HAVE_CONTEXT_TRACKING
# VIRT_CPU_ACCOUNTING_GEN dependency
depends on 64BIT
+ depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
select NO_HZ_COMMON
select RCU_USER_QS
select RCU_NOCB_CPU
--
1.8.3.1
From: Kevin Hilman <[email protected]>
With the 64-bit requirement removed from VIRT_CPU_ACCOUNTING_GEN,
allow ARM platforms to enable it. Since VIRT_CPU_ACCOUNTING_GEN is a
dependency for full NO_HZ, this allows ARM platforms to enable full
NO_HZ as well.
Signed-off-by: Kevin Hilman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Russell King <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Arm Linux <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
---
arch/arm/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1ad6fb6..323baf0 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -54,6 +54,7 @@ config ARM
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UID16
+ select HAVE_VIRT_CPU_ACCOUNTING_GEN
select IRQ_FORCED_THREADING
select KTIME_SCALAR
select MODULES_USE_ELF_REL
--
1.8.3.1
From: Kevin Hilman <[email protected]>
The CONFIG_64BIT requirement on vtime can finally be removed
since we now depend on HAVE_VIRT_CPU_ACCOUNTING_GEN which
already takes care of the arch ability to handle nsecs based
cputime_t safely.
Signed-off-by: Kevin Hilman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Russell King <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Arm Linux <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
---
init/Kconfig | 2 +-
kernel/time/Kconfig | 1 -
2 files changed, 1 insertion(+), 2 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index 68c1a0e..841e79c 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -354,7 +354,7 @@ config VIRT_CPU_ACCOUNTING_NATIVE
config VIRT_CPU_ACCOUNTING_GEN
bool "Full dynticks CPU time accounting"
- depends on HAVE_CONTEXT_TRACKING && 64BIT
+ depends on HAVE_CONTEXT_TRACKING
depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
select VIRT_CPU_ACCOUNTING
select CONTEXT_TRACKING
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index f148475..3ce6e8c 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -100,7 +100,6 @@ config NO_HZ_FULL
# RCU_USER_QS dependency
depends on HAVE_CONTEXT_TRACKING
# VIRT_CPU_ACCOUNTING_GEN dependency
- depends on 64BIT
depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
select NO_HZ_COMMON
select RCU_USER_QS
--
1.8.3.1
Frederic Weisbecker <[email protected]> writes:
> Hi Kevin,
>
> Your patchset was fine but I just did a second round. Namely I did the following changes:
>
> * Drop the 64 bits dependency after we settle the new dependency on HAVE_VIRT_CPU_ACCOUNTING_GEN
> and not before. This way we don't have a middle state that loose the dependency in the middle of
> the patchset. Probablyt no big deal but it looks more natural this way.
>
> * Refined a few changelogs.
>
> If you're ok I'll send a pull request to Ingo.
Looks good to me, thanks.
Kevin
> Kevin Hilman (3):
> vtime: Add HAVE_VIRT_CPU_ACCOUNTING_GEN Kconfig
> nohz: Drop generic vtime obsolete dependency on CONFIG_64BIT
> ARM: Kconfig: allow full nohz CPU accounting
>
> arch/Kconfig | 12 ++++++++++++
> arch/arm/Kconfig | 1 +
> init/Kconfig | 3 ++-
> kernel/time/Kconfig | 2 +-
> 4 files changed, 16 insertions(+), 2 deletions(-)
* Frederic Weisbecker <[email protected]> wrote:
> config VIRT_CPU_ACCOUNTING_GEN
> bool "Full dynticks CPU time accounting"
> - depends on HAVE_CONTEXT_TRACKING && 64BIT
> + depends on HAVE_CONTEXT_TRACKING
> depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
> select VIRT_CPU_ACCOUNTING
> select CONTEXT_TRACKING
> @@ -100,7 +100,6 @@ config NO_HZ_FULL
> # RCU_USER_QS dependency
> depends on HAVE_CONTEXT_TRACKING
> # VIRT_CPU_ACCOUNTING_GEN dependency
> - depends on 64BIT
> depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Yay!
Thanks,
Ingo