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authorAkira Takeuchi <takeuchi.akr@jp.panasonic.com>2010-10-27 17:28:52 +0100
committerDavid Howells <dhowells@redhat.com>2010-10-27 17:28:52 +0100
commit278d91c4609d55202c1e63d5fc5f01466cc7bbab (patch)
tree8b0c863837508959430c1741e2e5a2d37d2890d4 /arch/mn10300/Kconfig
parent965ea4bbb9ae926358273368144ba838c561bc38 (diff)
downloadop-kernel-dev-278d91c4609d55202c1e63d5fc5f01466cc7bbab.zip
op-kernel-dev-278d91c4609d55202c1e63d5fc5f01466cc7bbab.tar.gz
MN10300: Make the FPU operate in non-lazy mode under SMP
Make the FPU operate in non-lazy mode under SMP so that when the process that is currently using the FPU migrates to a different CPU, we don't have to ping its previous CPU to flush the FPU context. Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com> Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com> Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'arch/mn10300/Kconfig')
-rw-r--r--arch/mn10300/Kconfig15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index 7bd920b..a1f334c 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -140,6 +140,21 @@ config FPU
default y
depends on MN10300_PROC_MN103E010
+config LAZY_SAVE_FPU
+ bool "Save FPU state lazily"
+ default y
+ depends on FPU && !SMP
+ help
+ Enable this to be lazy in the saving of the FPU state to the owning
+ task's thread struct. This is useful if most tasks on the system
+ don't use the FPU as only those tasks that use it will pass it
+ between them, and the state needn't be saved for a task that isn't
+ using it.
+
+ This can't be so easily used on SMP as the process that owns the FPU
+ state on a CPU may be currently running on another CPU, so for the
+ moment, it is disabled.
+
source "arch/mn10300/mm/Kconfig.cache"
config MN10300_TLB_USE_PIDR
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