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authorHeiko Carstens <heiko.carstens@de.ibm.com>2006-02-17 13:52:48 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-17 13:59:27 -0800
commit54330456b2e3398743586254f6d7695061ea0d49 (patch)
tree1527f8c2a5ff6247e88b73f6529b2b6b7aa9d724 /arch/s390
parent37a3302618a51520e2056494715ea6b4776dd8ab (diff)
downloadlinux-54330456b2e3398743586254f6d7695061ea0d49.tar.bz2
[PATCH] s390: smp initialization speed
The last changes that introduced the additional_cpus command line parameter also introduced a regression regarding smp initialization speed. In smp_setup_cpu_possible_map() cpu_present_map is set to the same value as cpu_possible_map. Especially that means that bits in the present map will be set for cpus that are not present. This will cause a slow down in the initial cpu_up() loop in smp_init() since trying to take cpus online that aren't present takes a while. Fix this by setting only bits for present cpus in cpu_present_map and set cpu_present_map to cpu_possible_map in smp_cpus_done(). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/smp.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index d0a2745aec7f..7dbe00c76c6b 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -677,17 +677,21 @@ static unsigned int __initdata possible_cpus;
void __init smp_setup_cpu_possible_map(void)
{
- unsigned int pcpus, cpu;
+ unsigned int phy_cpus, pos_cpus, cpu;
- pcpus = min(smp_count_cpus() + additional_cpus, (unsigned int) NR_CPUS);
+ phy_cpus = smp_count_cpus();
+ pos_cpus = min(phy_cpus + additional_cpus, (unsigned int) NR_CPUS);
if (possible_cpus)
- pcpus = min(possible_cpus, (unsigned int) NR_CPUS);
+ pos_cpus = min(possible_cpus, (unsigned int) NR_CPUS);
- for (cpu = 0; cpu < pcpus; cpu++)
+ for (cpu = 0; cpu < pos_cpus; cpu++)
cpu_set(cpu, cpu_possible_map);
- cpu_present_map = cpu_possible_map;
+ phy_cpus = min(phy_cpus, pos_cpus);
+
+ for (cpu = 0; cpu < phy_cpus; cpu++)
+ cpu_set(cpu, cpu_present_map);
}
#ifdef CONFIG_HOTPLUG_CPU
@@ -843,6 +847,7 @@ void __devinit smp_prepare_boot_cpu(void)
void smp_cpus_done(unsigned int max_cpus)
{
+ cpu_present_map = cpu_possible_map;
}
/*