On 17/11/2020 16.42, Janosch Frank wrote:
> Let's only read the information once and pass a pointer to it instead
> of calling sclp multiple times.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> lib/s390x/io.c | 1 +
> lib/s390x/sclp.c | 29 +++++++++++++++++++++++------
> lib/s390x/sclp.h | 3 +++
> lib/s390x/smp.c | 23 +++++++++--------------
> 4 files changed, 36 insertions(+), 20 deletions(-)
>
> diff --git a/lib/s390x/io.c b/lib/s390x/io.c
> index c0f0bf7..e19a1f3 100644
> --- a/lib/s390x/io.c
> +++ b/lib/s390x/io.c
> @@ -36,6 +36,7 @@ void setup(void)
> {
> setup_args_progname(ipl_args);
> setup_facilities();
> + sclp_read_info();
> sclp_console_setup();
> sclp_memory_setup();
> smp_setup();
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 4054d0e..ea6324e 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -25,6 +25,8 @@ extern unsigned long stacktop;
> static uint64_t storage_increment_size;
> static uint64_t max_ram_size;
> static uint64_t ram_size;
> +char _read_info[PAGE_SIZE] __attribute__((__aligned__(4096)));
> +static ReadInfo *read_info;
>
> char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> static volatile bool sclp_busy;
> @@ -110,6 +112,22 @@ static void sclp_read_scp_info(ReadInfo *ri, int length)
> report_abort("READ_SCP_INFO failed");
> }
>
> +void sclp_read_info(void)
> +{
> + sclp_read_scp_info((void *)_read_info, SCCB_SIZE);
> + read_info = (ReadInfo *)_read_info;
> +}
> +
> +int sclp_get_cpu_num(void)
> +{
> + return read_info->entries_cpu;
> +}
[...]
> int smp_query_num_cpus(void)
> {
> - struct ReadCpuInfo *info = (void *)cpu_info_buffer;
> - return info->nr_configured;
> + return sclp_get_cpu_num();
> }
You've changed from ->nr_configured to ->entries_cpu ... I assume that's ok?
Worth to mention the change and rationale in the patch description?
> struct cpu *smp_cpu_from_addr(uint16_t addr)
> @@ -245,22 +244,18 @@ extern uint64_t *stackptr;
> void smp_setup(void)
> {
> int i = 0;
> + int num = smp_query_num_cpus();
> unsigned short cpu0_addr = stap();
> - struct ReadCpuInfo *info = (void *)cpu_info_buffer;
> + struct CPUEntry *entry = sclp_get_cpu_entries();
>
> - spin_lock(&lock);
> - sclp_mark_busy();
> - info->h.length = PAGE_SIZE;
> - sclp_service_call(SCLP_READ_CPU_INFO, cpu_info_buffer);
> + if (num > 1)
> + printf("SMP: Initializing, found %d cpus\n", num);
>
> - if (smp_query_num_cpus() > 1)
> - printf("SMP: Initializing, found %d cpus\n", info->nr_configured);
> -
> - cpus = calloc(info->nr_configured, sizeof(cpus));
> - for (i = 0; i < info->nr_configured; i++) {
> - cpus[i].addr = info->entries[i].address;
> + cpus = calloc(num, sizeof(cpus));
> + for (i = 0; i < num; i++) {
> + cpus[i].addr = entry[i].address;
> cpus[i].active = false;
> - if (info->entries[i].address == cpu0_addr) {
> + if (entry[i].address == cpu0_addr) {
> cpu0 = &cpus[i];
> cpu0->stack = stackptr;
> cpu0->lowcore = (void *)0;
>
What about smp_teardown()? It seems to use cpu_info_buffer->nr_configured,
too, which is now likely not valid anymore?
Thomas
