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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-12-25 13:39:23 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-12-25 13:39:14 +0100 |
| commit | 2b1a61f0a8c714c96277bf16a823a84bafa1397d (patch) | |
| tree | a874b7717e33cb408bfd7edff115e8dba83040c2 | |
| parent | [S390] add new machine types to setup_hwcaps. (diff) | |
| download | linux-2b1a61f0a8c714c96277bf16a823a84bafa1397d.tar.xz linux-2b1a61f0a8c714c96277bf16a823a84bafa1397d.zip | |
[S390] cpu topology: introduce kernel parameter
Introduce a topology=[on|off] kernel parameter which allows to switch
cpu topology on/off. Default will be off, since it looks like that for
some workloards this doesn't behave very well (on s390).
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| -rw-r--r-- | Documentation/kernel-parameters.txt | 8 | ||||
| -rw-r--r-- | arch/s390/kernel/topology.c | 12 |
2 files changed, 19 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index c9115c1b672c..09ede6c90ad7 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2252,6 +2252,14 @@ and is between 256 and 4096 characters. It is defined in the file See comment before function dc390_setup() in drivers/scsi/tmscsim.c. + topology= [S390] + Format: {off | on} + Specify if the kernel should make use of the cpu + topology informations if the hardware supports these. + The scheduler will make use of these informations and + e.g. base its process migration decisions on it. + Default is off. + tp720= [HW,PS2] trix= [HW,OSS] MediaTrix AudioTrix Pro diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c index 36faac50e774..71e6f56bfead 100644 --- a/arch/s390/kernel/topology.c +++ b/arch/s390/kernel/topology.c @@ -58,6 +58,7 @@ struct core_info { cpumask_t mask; }; +static int topology_enabled; static void topology_work_fn(struct work_struct *work); static struct tl_info *tl_info; static struct core_info core_info; @@ -78,7 +79,7 @@ cpumask_t cpu_coregroup_map(unsigned int cpu) cpumask_t mask; cpus_clear(mask); - if (!machine_has_topology) + if (!topology_enabled || !machine_has_topology) return cpu_possible_map; spin_lock_irqsave(&topology_lock, flags); while (core) { @@ -263,6 +264,15 @@ static void topology_interrupt(__u16 code) schedule_work(&topology_work); } +static int __init early_parse_topology(char *p) +{ + if (strncmp(p, "on", 2)) + return 0; + topology_enabled = 1; + return 0; +} +early_param("topology", early_parse_topology); + static int __init init_topology_update(void) { int rc; |