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| author |   Heiko Carstens <heiko.carstens@de.ibm.com> | 2006-02-17 13:52:48 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-17 13:59:27 -0800 |
| commit | 54330456b2e3398743586254f6d7695061ea0d49 (patch) | |
| tree | 1527f8c2a5ff6247e88b73f6529b2b6b7aa9d724 | |
| parent | [PATCH] s390: possible_cpus parameter (diff) | |
| download | linux-dev-54330456b2e3398743586254f6d7695061ea0d49.tar.xz linux-dev-54330456b2e3398743586254f6d7695061ea0d49.zip | |
[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>
| -rw-r--r-- | arch/s390/kernel/smp.c | 15 |
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; } /* |