ia64/xen-unstable

changeset 8042:f887ddae2b03

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>
author kaf24@firebug.cl.cam.ac.uk
date Thu Nov 24 20:01:16 2005 +0100 (2005-11-24)
parents 877d738e7a40
children 78b5e590be34
files linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_32 linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_64 linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_32 linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_64 linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_32 linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_64 linux-2.6-xen-sparse/arch/xen/i386/Kconfig linux-2.6-xen-sparse/arch/xen/x86_64/Kconfig
line diff
     1.1 --- a/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_32	Thu Nov 24 19:49:15 2005 +0100
     1.2 +++ b/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_32	Thu Nov 24 20:01:16 2005 +0100
     1.3 @@ -35,7 +35,6 @@ CONFIG_EXPERIMENTAL=y
     1.4  # CONFIG_CLEAN_COMPILE is not set
     1.5  CONFIG_BROKEN=y
     1.6  CONFIG_BROKEN_ON_SMP=y
     1.7 -CONFIG_LOCK_KERNEL=y
     1.8  CONFIG_INIT_ENV_ARG_LIMIT=32
     1.9  
    1.10  #
    1.11 @@ -125,8 +124,6 @@ CONFIG_X86_USE_PPRO_CHECKSUM=y
    1.12  # CONFIG_HPET_TIMER is not set
    1.13  # CONFIG_HPET_EMULATE_RTC is not set
    1.14  # CONFIG_SMP is not set
    1.15 -CONFIG_PREEMPT=y
    1.16 -CONFIG_PREEMPT_BKL=y
    1.17  # CONFIG_X86_REBOOTFIXUPS is not set
    1.18  CONFIG_MICROCODE=y
    1.19  CONFIG_X86_CPUID=y
    1.20 @@ -141,7 +138,6 @@ CONFIG_HIGHMEM4G=y
    1.21  # CONFIG_HIGHMEM64G is not set
    1.22  CONFIG_HIGHMEM=y
    1.23  CONFIG_MTRR=y
    1.24 -CONFIG_HAVE_DEC_LOCK=y
    1.25  # CONFIG_REGPARM is not set
    1.26  CONFIG_X86_LOCAL_APIC=y
    1.27  CONFIG_X86_IO_APIC=y
    1.28 @@ -1259,7 +1255,6 @@ CONFIG_MAGIC_SYSRQ=y
    1.29  CONFIG_LOG_BUF_SHIFT=14
    1.30  # CONFIG_SCHEDSTATS is not set
    1.31  # CONFIG_DEBUG_SLAB is not set
    1.32 -# CONFIG_DEBUG_PREEMPT is not set
    1.33  # CONFIG_DEBUG_SPINLOCK is not set
    1.34  # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
    1.35  # CONFIG_DEBUG_KOBJECT is not set
     2.1 --- a/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_64	Thu Nov 24 19:49:15 2005 +0100
     2.2 +++ b/linux-2.6-xen-sparse/arch/xen/configs/xen0_defconfig_x86_64	Thu Nov 24 20:01:16 2005 +0100
     2.3 @@ -90,7 +90,6 @@ CONFIG_GENERIC_CALIBRATE_DELAY=y
     2.4  CONFIG_X86_GOOD_APIC=y
     2.5  # CONFIG_HPET_TIMER is not set
     2.6  # CONFIG_SMP is not set
     2.7 -# CONFIG_PREEMPT is not set
     2.8  CONFIG_MICROCODE=y
     2.9  # CONFIG_X86_CPUID is not set
    2.10  CONFIG_SWIOTLB=y
     3.1 --- a/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_32	Thu Nov 24 19:49:15 2005 +0100
     3.2 +++ b/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_32	Thu Nov 24 20:01:16 2005 +0100
     3.3 @@ -125,8 +125,6 @@ CONFIG_SMP=y
     3.4  CONFIG_SMP_ALTERNATIVES=y
     3.5  CONFIG_NR_CPUS=8
     3.6  # CONFIG_SCHED_SMT is not set
     3.7 -CONFIG_PREEMPT=y
     3.8 -CONFIG_PREEMPT_BKL=y
     3.9  # CONFIG_X86_REBOOTFIXUPS is not set
    3.10  CONFIG_X86_CPUID=y
    3.11  
    3.12 @@ -550,7 +548,6 @@ CONFIG_MAGIC_SYSRQ=y
    3.13  CONFIG_LOG_BUF_SHIFT=14
    3.14  # CONFIG_SCHEDSTATS is not set
    3.15  # CONFIG_DEBUG_SLAB is not set
    3.16 -# CONFIG_DEBUG_PREEMPT is not set
    3.17  # CONFIG_DEBUG_SPINLOCK is not set
    3.18  # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
    3.19  # CONFIG_DEBUG_KOBJECT is not set
     4.1 --- a/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_64	Thu Nov 24 19:49:15 2005 +0100
     4.2 +++ b/linux-2.6-xen-sparse/arch/xen/configs/xenU_defconfig_x86_64	Thu Nov 24 20:01:16 2005 +0100
     4.3 @@ -92,7 +92,6 @@ CONFIG_X86_GOOD_APIC=y
     4.4  CONFIG_SMP=y
     4.5  CONFIG_NR_CPUS=8
     4.6  # CONFIG_SCHED_SMT is not set
     4.7 -# CONFIG_PREEMPT is not set
     4.8  # CONFIG_MICROCODE is not set
     4.9  CONFIG_X86_CPUID=y
    4.10  # CONFIG_NUMA is not set
     5.1 --- a/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_32	Thu Nov 24 19:49:15 2005 +0100
     5.2 +++ b/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_32	Thu Nov 24 20:01:16 2005 +0100
     5.3 @@ -132,8 +132,6 @@ CONFIG_SMP=y
     5.4  CONFIG_SMP_ALTERNATIVES=y
     5.5  CONFIG_NR_CPUS=8
     5.6  # CONFIG_SCHED_SMT is not set
     5.7 -CONFIG_PREEMPT=y
     5.8 -CONFIG_PREEMPT_BKL=y
     5.9  # CONFIG_X86_REBOOTFIXUPS is not set
    5.10  CONFIG_MICROCODE=y
    5.11  CONFIG_X86_CPUID=m
    5.12 @@ -2951,7 +2949,6 @@ CONFIG_MAGIC_SYSRQ=y
    5.13  CONFIG_LOG_BUF_SHIFT=14
    5.14  # CONFIG_SCHEDSTATS is not set
    5.15  # CONFIG_DEBUG_SLAB is not set
    5.16 -CONFIG_DEBUG_PREEMPT=y
    5.17  # CONFIG_DEBUG_SPINLOCK is not set
    5.18  # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
    5.19  # CONFIG_DEBUG_KOBJECT is not set
     6.1 --- a/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_64	Thu Nov 24 19:49:15 2005 +0100
     6.2 +++ b/linux-2.6-xen-sparse/arch/xen/configs/xen_defconfig_x86_64	Thu Nov 24 20:01:16 2005 +0100
     6.3 @@ -95,7 +95,6 @@ CONFIG_X86_GOOD_APIC=y
     6.4  CONFIG_SMP=y
     6.5  CONFIG_NR_CPUS=8
     6.6  # CONFIG_SCHED_SMT is not set
     6.7 -# CONFIG_PREEMPT is not set
     6.8  CONFIG_MICROCODE=y
     6.9  # CONFIG_X86_CPUID is not set
    6.10  # CONFIG_NUMA is not set
     7.1 --- a/linux-2.6-xen-sparse/arch/xen/i386/Kconfig	Thu Nov 24 19:49:15 2005 +0100
     7.2 +++ b/linux-2.6-xen-sparse/arch/xen/i386/Kconfig	Thu Nov 24 20:01:16 2005 +0100
     7.3 @@ -415,17 +415,17 @@ config SCHED_SMT
     7.4  	  cost of slightly increased overhead in some places. If unsure say
     7.5  	  N here.
     7.6  
     7.7 -config PREEMPT
     7.8 -	bool "Preemptible Kernel"
     7.9 -	help
    7.10 -	  This option reduces the latency of the kernel when reacting to
    7.11 -	  real-time or interactive events by allowing a low priority process to
    7.12 -	  be preempted even if it is in kernel mode executing a system call.
    7.13 -	  This allows applications to run more reliably even when the system is
    7.14 -	  under load.
    7.15 -
    7.16 -	  Say Y here if you are building a kernel for a desktop, embedded
    7.17 -	  or real-time system.  Say N if you are unsure.
    7.18 +#config PREEMPT
    7.19 +#	bool "Preemptible Kernel"
    7.20 +#	help
    7.21 +#	  This option reduces the latency of the kernel when reacting to
    7.22 +#	  real-time or interactive events by allowing a low priority process to
    7.23 +#	  be preempted even if it is in kernel mode executing a system call.
    7.24 +#	  This allows applications to run more reliably even when the system is
    7.25 +#	  under load.
    7.26 +#
    7.27 +#	  Say Y here if you are building a kernel for a desktop, embedded
    7.28 +#	  or real-time system.  Say N if you are unsure.
    7.29  
    7.30  config PREEMPT_BKL
    7.31  	bool "Preempt The Big Kernel Lock"
     8.1 --- a/linux-2.6-xen-sparse/arch/xen/x86_64/Kconfig	Thu Nov 24 19:49:15 2005 +0100
     8.2 +++ b/linux-2.6-xen-sparse/arch/xen/x86_64/Kconfig	Thu Nov 24 20:01:16 2005 +0100
     8.3 @@ -224,21 +224,21 @@ config SMP
     8.4  
     8.5  	  If you don't know what to do here, say N.
     8.6  
     8.7 -config PREEMPT
     8.8 -	bool "Preemptible Kernel"
     8.9 -	---help---
    8.10 -	  This option reduces the latency of the kernel when reacting to
    8.11 -	  real-time or interactive events by allowing a low priority process to
    8.12 -	  be preempted even if it is in kernel mode executing a system call.
    8.13 -	  This allows applications to run more reliably even when the system is
    8.14 -	  under load. On contrary it may also break your drivers and add
    8.15 -	  priority inheritance problems to your system. Don't select it if
    8.16 -	  you rely on a stable system or have slightly obscure hardware.
    8.17 -	  It's also not very well tested on x86-64 currently.
    8.18 -	  You have been warned.
    8.19 -
    8.20 -	  Say Y here if you are feeling brave and building a kernel for a
    8.21 -	  desktop, embedded or real-time system.  Say N if you are unsure.
    8.22 +#config PREEMPT
    8.23 +#	bool "Preemptible Kernel"
    8.24 +#	---help---
    8.25 +#	  This option reduces the latency of the kernel when reacting to
    8.26 +#	  real-time or interactive events by allowing a low priority process to
    8.27 +#	  be preempted even if it is in kernel mode executing a system call.
    8.28 +#	  This allows applications to run more reliably even when the system is
    8.29 +#	  under load. On contrary it may also break your drivers and add
    8.30 +#	  priority inheritance problems to your system. Don't select it if
    8.31 +#	  you rely on a stable system or have slightly obscure hardware.
    8.32 +#	  It's also not very well tested on x86-64 currently.
    8.33 +#	  You have been warned.
    8.34 +#
    8.35 +#	  Say Y here if you are feeling brave and building a kernel for a
    8.36 +#	  desktop, embedded or real-time system.  Say N if you are unsure.
    8.37  
    8.38  config SCHED_SMT
    8.39  	bool "SMT (Hyperthreading) scheduler support"