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authorHeiko Carstens <heiko.carstens@de.ibm.com>2014-03-10 14:50:16 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2014-03-17 15:53:06 +0100
commitcf813db0b448b45b454f0983329c3c7b007f9ab7 (patch)
tree2ccbddbc0c1494d92e4fa4f1c2f7d337595e1dd2 /arch/s390
parent36a554021b44d146178ae98e598c9502a1269f7d (diff)
s390/smp: limit number of cpus in possible cpu mask
Limit the number of bits to the maximum number of cpus a machine can have. possible_cpu_mask typically will have more bits set than a machine may physically have. This results in wasted memory during per-cpu memory allocations, if the possible mask contains more cpus than physically possible for a given configuration. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/sclp.h1
-rw-r--r--arch/s390/kernel/smp.c8
2 files changed, 5 insertions, 4 deletions
diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h
index abaca2275c7a..2f5e9932b4de 100644
--- a/arch/s390/include/asm/sclp.h
+++ b/arch/s390/include/asm/sclp.h
@@ -46,6 +46,7 @@ int sclp_cpu_configure(u8 cpu);
int sclp_cpu_deconfigure(u8 cpu);
unsigned long long sclp_get_rnmax(void);
unsigned long long sclp_get_rzm(void);
+unsigned int sclp_get_max_cpu(void);
int sclp_sdias_blk_count(void);
int sclp_sdias_copy(void *dest, int blk_num, int nr_blks);
int sclp_chp_configure(struct chp_id chpid);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index a7125b62a9a6..8827883310dd 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -773,11 +773,11 @@ void __noreturn cpu_die(void)
void __init smp_fill_possible_mask(void)
{
- unsigned int possible, cpu;
+ unsigned int possible, sclp, cpu;
- possible = setup_possible_cpus;
- if (!possible)
- possible = MACHINE_IS_VM ? 64 : nr_cpu_ids;
+ sclp = sclp_get_max_cpu() ?: nr_cpu_ids;
+ possible = setup_possible_cpus ?: nr_cpu_ids;
+ possible = min(possible, sclp);
for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
set_cpu_possible(cpu, true);
}