lkml.org 
[lkml]   [2013]   [Sep]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/4] full_nohz: Kconfig: add HAVE_VIRT_CPU_ACCOUNTING_GEN
Date
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 <fweisbec@gmail.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
---
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


\
 
 \ /
  Last update: 2013-09-17 00:41    [W:0.062 / U:0.276 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site