Remove CONFIG_PREEMPT configuration option from Xen kernel builds.

The option reduces overall system performance and makes little sense
when running over a preemptive hypervisor. Removing the option also
fixes some hypothetical races.

The forthcoming voluntary-preemption option will make much more sense
to enable when running over Xen.

Signed-off-by: Keir Fraser <keir@xensource.com>

diff --git a/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_32 b/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_32
index bae115ecc7ee1386fd84e9155b5498c1e23dffe4..1370fc77d8521be16325a660263ba2c6b9bec80b 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_32
+++ b/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_32
@@ -35,7 +35,6 @@ CONFIG_EXPERIMENTAL=y
 # CONFIG_CLEAN_COMPILE is not set
 CONFIG_BROKEN=y
 CONFIG_BROKEN_ON_SMP=y
-CONFIG_LOCK_KERNEL=y
 CONFIG_INIT_ENV_ARG_LIMIT=32
 
 #
@@ -125,8 +124,6 @@ CONFIG_X86_USE_PPRO_CHECKSUM=y
 # CONFIG_HPET_TIMER is not set
 # CONFIG_HPET_EMULATE_RTC is not set
 # CONFIG_SMP is not set
-CONFIG_PREEMPT=y
-CONFIG_PREEMPT_BKL=y
 # CONFIG_X86_REBOOTFIXUPS is not set
 CONFIG_MICROCODE=y
 CONFIG_X86_CPUID=y
@@ -141,7 +138,6 @@ CONFIG_HIGHMEM4G=y
 # CONFIG_HIGHMEM64G is not set
 CONFIG_HIGHMEM=y
 CONFIG_MTRR=y
-CONFIG_HAVE_DEC_LOCK=y
 # CONFIG_REGPARM is not set
 CONFIG_X86_LOCAL_APIC=y
 CONFIG_X86_IO_APIC=y
@@ -1259,7 +1255,6 @@ CONFIG_MAGIC_SYSRQ=y
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_SCHEDSTATS is not set
 # CONFIG_DEBUG_SLAB is not set
-# CONFIG_DEBUG_PREEMPT is not set
 # CONFIG_DEBUG_SPINLOCK is not set
 # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
 # CONFIG_DEBUG_KOBJECT is not set

diff --git a/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_64 b/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_64
index cb54da3b0e6da59436c9afe1a13d16b37a8288f3..70897076f9b04561d1cc07a4d8ab40a5682ea8f0 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_64
+++ b/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_64
@@ -90,7 +90,6 @@ CONFIG_GENERIC_CALIBRATE_DELAY=y
 CONFIG_X86_GOOD_APIC=y
 # CONFIG_HPET_TIMER is not set
 # CONFIG_SMP is not set
-# CONFIG_PREEMPT is not set
 CONFIG_MICROCODE=y
 # CONFIG_X86_CPUID is not set
 CONFIG_SWIOTLB=y

diff --git a/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_32 b/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_32
index 0715a553615cfab6256ceacab05e142f181e2297..a4e9d33376c98899dbbc32d481f340df9e35aaae 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_32
+++ b/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_32
@@ -125,8 +125,6 @@ CONFIG_SMP=y
 CONFIG_SMP_ALTERNATIVES=y
 CONFIG_NR_CPUS=8
 # CONFIG_SCHED_SMT is not set
-CONFIG_PREEMPT=y
-CONFIG_PREEMPT_BKL=y
 # CONFIG_X86_REBOOTFIXUPS is not set
 CONFIG_X86_CPUID=y
 
@@ -550,7 +548,6 @@ CONFIG_MAGIC_SYSRQ=y
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_SCHEDSTATS is not set
 # CONFIG_DEBUG_SLAB is not set
-# CONFIG_DEBUG_PREEMPT is not set
 # CONFIG_DEBUG_SPINLOCK is not set
 # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
 # CONFIG_DEBUG_KOBJECT is not set

diff --git a/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_64 b/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_64
index 87ca4d45e1a494dd88484ce1d01a645d5121157d..7e9d1a5888cbc4e77e34dfdc5a3dde7347f832f7 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_64
+++ b/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_64
@@ -92,7 +92,6 @@ CONFIG_X86_GOOD_APIC=y
 CONFIG_SMP=y
 CONFIG_NR_CPUS=8
 # CONFIG_SCHED_SMT is not set
-# CONFIG_PREEMPT is not set
 # CONFIG_MICROCODE is not set
 CONFIG_X86_CPUID=y
 # CONFIG_NUMA is not set

diff --git a/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_32 b/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_32
index 6a210a8fc5918b5e0ba3b9bd99c96689e52d65b0..5bfa138e807fe479ef6ac5fa24beab864baeb646 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_32
+++ b/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_32
@@ -132,8 +132,6 @@ CONFIG_SMP=y
 CONFIG_SMP_ALTERNATIVES=y
 CONFIG_NR_CPUS=8
 # CONFIG_SCHED_SMT is not set
-CONFIG_PREEMPT=y
-CONFIG_PREEMPT_BKL=y
 # CONFIG_X86_REBOOTFIXUPS is not set
 CONFIG_MICROCODE=y
 CONFIG_X86_CPUID=m
@@ -2951,7 +2949,6 @@ CONFIG_MAGIC_SYSRQ=y
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_SCHEDSTATS is not set
 # CONFIG_DEBUG_SLAB is not set
-CONFIG_DEBUG_PREEMPT=y
 # CONFIG_DEBUG_SPINLOCK is not set
 # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
 # CONFIG_DEBUG_KOBJECT is not set

diff --git a/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_64 b/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_64
index 4a14a2d9ba9797fb1302be971647e9d30d8405d4..d5c01d3a6f357837572b5fbf48c9874cb0a84b0a 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_64
+++ b/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_64
@@ -95,7 +95,6 @@ CONFIG_X86_GOOD_APIC=y
 CONFIG_SMP=y
 CONFIG_NR_CPUS=8
 # CONFIG_SCHED_SMT is not set
-# CONFIG_PREEMPT is not set
 CONFIG_MICROCODE=y
 # CONFIG_X86_CPUID is not set
 # CONFIG_NUMA is not set

diff --git a/linux-2.6-xen-sparse/arch/xen/i386/Kconfig b/linux-2.6-xen-sparse/arch/xen/i386/Kconfig
index 91873ae4b6b9cfc3de720b6a6bc2ecd6ca39a083..d301b89a6212ce0901bb509ee54b7c51c5ee455a 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/i386/Kconfig
+++ b/linux-2.6-xen-sparse/arch/xen/i386/Kconfig
@@ -415,17 +415,17 @@ config SCHED_SMT
          cost of slightly increased overhead in some places. If unsure say
          N here.
 
-config PREEMPT
-       bool "Preemptible Kernel"
-       help
-         This option reduces the latency of the kernel when reacting to
-         real-time or interactive events by allowing a low priority process to
-         be preempted even if it is in kernel mode executing a system call.
-         This allows applications to run more reliably even when the system is
-         under load.
-
-         Say Y here if you are building a kernel for a desktop, embedded
-         or real-time system.  Say N if you are unsure.
+#config PREEMPT
+#      bool "Preemptible Kernel"
+#      help
+#        This option reduces the latency of the kernel when reacting to
+#        real-time or interactive events by allowing a low priority process to
+#        be preempted even if it is in kernel mode executing a system call.
+#        This allows applications to run more reliably even when the system is
+#        under load.
+#
+#        Say Y here if you are building a kernel for a desktop, embedded
+#        or real-time system.  Say N if you are unsure.
 
 config PREEMPT_BKL
        bool "Preempt The Big Kernel Lock"

diff --git a/linux-2.6-xen-sparse/arch/xen/x86_64/Kconfig b/linux-2.6-xen-sparse/arch/xen/x86_64/Kconfig
index efed94b44595c2e977f82b4240cc1e1facfcc5d7..b047c9528dc38b4c8c45835354c02009e0ee6814 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/x86_64/Kconfig
+++ b/linux-2.6-xen-sparse/arch/xen/x86_64/Kconfig
@@ -224,21 +224,21 @@ config SMP
 
          If you don't know what to do here, say N.
 
-config PREEMPT
-       bool "Preemptible Kernel"
-       ---help---
-         This option reduces the latency of the kernel when reacting to
-         real-time or interactive events by allowing a low priority process to
-         be preempted even if it is in kernel mode executing a system call.
-         This allows applications to run more reliably even when the system is
-         under load. On contrary it may also break your drivers and add
-         priority inheritance problems to your system. Don't select it if
-         you rely on a stable system or have slightly obscure hardware.
-         It's also not very well tested on x86-64 currently.
-         You have been warned.
-
-         Say Y here if you are feeling brave and building a kernel for a
-         desktop, embedded or real-time system.  Say N if you are unsure.
+#config PREEMPT
+#      bool "Preemptible Kernel"
+#      ---help---
+#        This option reduces the latency of the kernel when reacting to
+#        real-time or interactive events by allowing a low priority process to
+#        be preempted even if it is in kernel mode executing a system call.
+#        This allows applications to run more reliably even when the system is
+#        under load. On contrary it may also break your drivers and add
+#        priority inheritance problems to your system. Don't select it if
+#        you rely on a stable system or have slightly obscure hardware.
+#        It's also not very well tested on x86-64 currently.
+#        You have been warned.
+#
+#        Say Y here if you are feeling brave and building a kernel for a
+#        desktop, embedded or real-time system.  Say N if you are unsure.
 
 config SCHED_SMT
        bool "SMT (Hyperthreading) scheduler support"