With HAVE_VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. In order to use that feature, arch code should be audited 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.
Therefore, add CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN which arches can enabled after they've been audited for potential races. This option is automatically enabled on 64-bit platforms. Feature requested by Frederic Weisbecker. Cc: Frederic Weisbecker <[email protected]> Signed-off-by: Kevin Hilman <[email protected]> --- arch/Kconfig | 11 +++++++++++ init/Kconfig | 1 + 2 files changed, 12 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 1feb169..3c94a2d 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -356,6 +356,17 @@ config HAVE_CONTEXT_TRACKING config HAVE_VIRT_CPU_ACCOUNTING bool +config HAVE_VIRT_CPU_ACCOUNTING_GEN + bool + default y if 64BIT + help + With HAVE_VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. + Before enabling this option, arch code must be audited + 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 e9cd23b..7c283a5 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 + depends on HAVE_VIRT_CPU_ACCOUNTING_GEN select VIRT_CPU_ACCOUNTING select CONTEXT_TRACKING help -- 1.8.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
