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author | Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> | 2010-10-06 12:36:59 +0400 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-11-29 07:48:19 +0300 |
commit | 99d86705253dcf728dbbec4d694a6764b6edb70c (patch) | |
tree | e4c68adab6448463a77141c1797671417f58242c /arch/powerpc/kernel/smp.c | |
parent | 787d44caa5bca249d8781d21b626c417f1e3cfc4 (diff) | |
download | linux-99d86705253dcf728dbbec4d694a6764b6edb70c.tar.xz |
powerpc: Cleanup APIs for cpu/thread/core mappings
These APIs take logical cpu number as input
Change cpu_first_thread_in_core() to cpu_first_thread_sibling()
Change cpu_last_thread_in_core() to cpu_last_thread_sibling()
These APIs convert core number (index) to logical cpu/thread numbers
Add cpu_first_thread_of_core(int core)
Changed cpu_thread_to_core() to cpu_core_index_of_thread(int cpu)
The goal is to make 'threads_per_core' accessible to the
pseries_energy module. Instead of making an API to read
threads_per_core, this is a higher level wrapper function to
convert from logical cpu number to core number.
The current APIs cpu_first_thread_in_core() and
cpu_last_thread_in_core() returns logical CPU number while
cpu_thread_to_core() returns core number or index which is
not a logical CPU number. The new APIs are now clearly named to
distinguish 'core number' versus first and last 'logical cpu
number' in that core.
The new APIs cpu_{first,last}_thread_sibling() work on
logical cpu numbers. While cpu_first_thread_of_core() and
cpu_core_index_of_thread() work on core index.
Example usage: (4 threads per core system)
cpu_first_thread_sibling(5) = 4
cpu_last_thread_sibling(5) = 7
cpu_core_index_of_thread(5) = 1
cpu_first_thread_of_core(1) = 4
cpu_core_index_of_thread() is used in cpu_to_drc_index() in the
module and cpu_first_thread_of_core() is used in
drc_index_to_cpu() in the module.
Make API changes to few callers. Export symbols for use in modules.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/smp.c')
-rw-r--r-- | arch/powerpc/kernel/smp.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 68034bbf2e4f..981360509172 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -466,7 +466,20 @@ out: return id; } -/* Must be called when no change can occur to cpu_present_mask, +/* Helper routines for cpu to core mapping */ +int cpu_core_index_of_thread(int cpu) +{ + return cpu >> threads_shift; +} +EXPORT_SYMBOL_GPL(cpu_core_index_of_thread); + +int cpu_first_thread_of_core(int core) +{ + return core << threads_shift; +} +EXPORT_SYMBOL_GPL(cpu_first_thread_of_core); + +/* Must be called when no change can occur to cpu_present_map, * i.e. during cpu online or offline. */ static struct device_node *cpu_to_l2cache(int cpu) @@ -514,7 +527,7 @@ int __devinit start_secondary(void *unused) notify_cpu_starting(cpu); set_cpu_online(cpu, true); /* Update sibling maps */ - base = cpu_first_thread_in_core(cpu); + base = cpu_first_thread_sibling(cpu); for (i = 0; i < threads_per_core; i++) { if (cpu_is_offline(base + i)) continue; @@ -600,7 +613,7 @@ int __cpu_disable(void) return err; /* Update sibling maps */ - base = cpu_first_thread_in_core(cpu); + base = cpu_first_thread_sibling(cpu); for (i = 0; i < threads_per_core; i++) { cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i)); cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu)); |