diff options
| author | Kevin Hilman <khilman@linaro.org> | 2013-09-17 00:28:21 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-09-30 15:35:53 +0200 |
| commit | 554b0004d0ec4fbd11e08668dfc400f211e8d5c5 (patch) | |
| tree | 962305270252e407cd887ba9ed949bde346b8f81 | |
| parent | Linux 3.12-rc3 (diff) | |
| download | linux-554b0004d0ec4fbd11e08668dfc400f211e8d5c5.tar.xz linux-554b0004d0ec4fbd11e08668dfc400f211e8d5c5.zip | |
vtime: Add HAVE_VIRT_CPU_ACCOUNTING_GEN Kconfig
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 <khilman@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Arm Linux <linux-arm-kernel@lists.infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| -rw-r--r-- | arch/Kconfig | 12 | ||||
| -rw-r--r-- | init/Kconfig | 1 | ||||
| -rw-r--r-- | kernel/time/Kconfig | 1 |
3 files changed, 14 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index af2cc6eabcc7..185f8b007643 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 3ecd8a1178f1..68c1a0ed704d 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 2b62fe86f9ec..f148475e5194 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 |