This patch updates the handling of the smt-enabled=X boot option to handle
settings on systems with more than two threads per core. This change involves
moving all of the handling of the boot option to the check_smt_enabled()
routine and the calling of this routine in setup_system() until after the
smp_setup_cpu_maps() call. This is done so that we can use the
threads_per_core variable when validating the smt boot option specified.
Signed-off-by: Nathan Fontenot<nf...@austin.ibm.com>
---
arch/powerpc/kernel/setup_64.c | 61 ++++++++++++++++++++---------------
arch/powerpc/platforms/pseries/smp.c | 11 ++++--
2 files changed, 42 insertions(+), 30 deletions(-)
Index: powerpc/arch/powerpc/kernel/setup_64.c
===================================================================
--- powerpc.orig/arch/powerpc/kernel/setup_64.c 2010-05-12 08:33:38.000000000
-0500
+++ powerpc/arch/powerpc/kernel/setup_64.c 2010-05-12 08:48:10.000000000
-0500
@@ -95,7 +95,7 @@
#ifdef CONFIG_SMP
-static int smt_enabled_cmdline;
+static char *smt_enabled_cmdline;
/* Look for ibm,smt-enabled OF option */
static void check_smt_enabled(void)
@@ -103,37 +103,46 @@
struct device_node *dn;
const char *smt_option;
- /* Allow the command line to overrule the OF option */
- if (smt_enabled_cmdline)
- return;
-
- dn = of_find_node_by_path("/options");
+ /* Default to enabling all threads */
+ smt_enabled_at_boot = threads_per_core;
- if (dn) {
- smt_option = of_get_property(dn, "ibm,smt-enabled", NULL);
+ /* Allow the command line to overrule the OF option */
+ if (smt_enabled_cmdline) {
+ if (!strcmp(smt_enabled_cmdline, "on"))
+ smt_enabled_at_boot = threads_per_core;
+ else if (!strcmp(smt_enabled_cmdline, "off"))
+ smt_enabled_at_boot = 0;
+ else {
+ long smt;
+ int rc;
+
+ rc = strict_strtol(smt_enabled_cmdline, 10,&smt);
+ if (!rc)
+ smt_enabled_at_boot =
+ min(threads_per_core, (int)smt);
+ }
+ } else {
+ dn = of_find_node_by_path("/options");
+ if (dn) {
+ smt_option = of_get_property(dn, "ibm,smt-enabled",
+ NULL);
+
+ if (smt_option) {
+ if (!strcmp(smt_option, "on"))
+ smt_enabled_at_boot = threads_per_core;
+ else if (!strcmp(smt_option, "off"))
+ smt_enabled_at_boot = 0;
+ }
- if (smt_option) {
- if (!strcmp(smt_option, "on"))
- smt_enabled_at_boot = 1;
- else if (!strcmp(smt_option, "off"))
- smt_enabled_at_boot = 0;
- }
- }
+ of_node_put(dn);
+ }
+ }
}
/* Look for smt-enabled= cmdline option */
static int __init early_smt_enabled(char *p)
{
- smt_enabled_cmdline = 1;
-
- if (!p)
- return 0;
-
- if (!strcmp(p, "on") || !strcmp(p, "1"))
- smt_enabled_at_boot = 1;
- else if (!strcmp(p, "off") || !strcmp(p, "0"))
- smt_enabled_at_boot = 0;
-
+ smt_enabled_cmdline = p;
return 0;
}
early_param("smt-enabled", early_smt_enabled);
@@ -390,8 +399,8 @@
*/
xmon_setup();
- check_smt_enabled();
smp_setup_cpu_maps();
+ check_smt_enabled();
#ifdef CONFIG_SMP
/* Release secondary cpus out of their spinloops at 0x60 now that
Index: powerpc/arch/powerpc/platforms/pseries/smp.c
===================================================================
--- powerpc.orig/arch/powerpc/platforms/pseries/smp.c 2010-05-12
08:33:38.000000000 -0500
+++ powerpc/arch/powerpc/platforms/pseries/smp.c 2010-05-12
08:36:09.000000000 -0500
@@ -154,10 +154,13 @@
/* Special case - we inhibit secondary thread startup
* during boot if the user requests it.
*/
- if (system_state< SYSTEM_RUNNING&&
- cpu_has_feature(CPU_FTR_SMT)&&
- !smt_enabled_at_boot&& cpu_thread_in_core(nr) != 0)
- return 0;
+ if (system_state< SYSTEM_RUNNING&& cpu_has_feature(CPU_FTR_SMT)) {
+ if (!smt_enabled_at_boot&& cpu_thread_in_core(nr) != 0)
+ return 0;
+ if (smt_enabled_at_boot
+ && cpu_thread_in_core(nr)>= smt_enabled_at_boot)
+ return 0;
+ }
return 1;
}
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