The patch titled
adjust nosmp handling
has been added to the -mm tree. Its filename is
adjust-nosmp-handling.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: adjust nosmp handling
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Especially when !CONFIG_HOTPLUG_CPU, avoid needlessy allocating resources for
CPUs that can never become available.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/main.c | 42 +++++++++++++++++++++++++++---------------
1 files changed, 27 insertions(+), 15 deletions(-)
diff -puN init/main.c~adjust-nosmp-handling init/main.c
--- a/init/main.c~adjust-nosmp-handling
+++ a/init/main.c
@@ -115,20 +115,9 @@ static char *static_command_line;
static char *execute_command;
static char *ramdisk_execute_command;
+#ifdef CONFIG_SMP
/* Setup configured maximum number of CPUs to activate */
-static unsigned int max_cpus = NR_CPUS;
-
-/*
- * If set, this is an indication to the drivers that reset the underlying
- * device before going ahead with the initialization otherwise driver might
- * rely on the BIOS and skip the reset operation.
- *
- * This is useful if kernel is booting in an unreliable environment.
- * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
- * skipped and devices will be in unknown state.
- */
-unsigned int reset_devices;
-EXPORT_SYMBOL(reset_devices);
+static unsigned int __initdata max_cpus = NR_CPUS;
/*
* Setup routine for controlling SMP activation
@@ -143,10 +132,10 @@ EXPORT_SYMBOL(reset_devices);
static int __init nosmp(char *str)
{
max_cpus = 0;
- return 1;
+ return 0;
}
-__setup("nosmp", nosmp);
+early_param("nosmp", nosmp);
static int __init maxcpus(char *str)
{
@@ -155,6 +144,21 @@ static int __init maxcpus(char *str)
}
__setup("maxcpus=", maxcpus);
+#else
+#define max_cpus NR_CPUS
+#endif
+
+/*
+ * If set, this is an indication to the drivers that reset the underlying
+ * device before going ahead with the initialization otherwise driver might
+ * rely on the BIOS and skip the reset operation.
+ *
+ * This is useful if kernel is booting in an unreliable environment.
+ * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
+ * skipped and devices will be in unknown state.
+ */
+unsigned int reset_devices;
+EXPORT_SYMBOL(reset_devices);
static int __init set_reset_devices(char *str)
{
@@ -368,6 +372,10 @@ static void __init smp_init(void)
{
unsigned int cpu;
+#ifndef CONFIG_HOTPLUG_CPU
+ cpu_possible_map = cpu_present_map;
+#endif
+
/* FIXME: This should be done in userspace --RR */
for_each_present_cpu(cpu) {
if (num_online_cpus() >= max_cpus)
@@ -512,6 +520,10 @@ asmlinkage void __init start_kernel(void
setup_arch(&command_line);
setup_command_line(command_line);
unwind_setup();
+#ifndef CONFIG_HOTPLUG_CPU
+ if (max_cpus < 2)
+ cpu_possible_map = cpu_online_map;
+#endif
setup_per_cpu_areas();
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
_
Patches currently in -mm which might be from jbeulich@xxxxxxxxxx are
remove-pci_dac_dma_-apis.patch
more-fix-x86_64-mm-xen-xen-smp-guest-support.patch
i386-minor-nx-handling-adjustment.patch
mm-fix-improper-init-type-section-references.patch
page-table-handling-cleanup.patch
modpost-white-list-pattern-adjustment.patch
adjust-nosmp-handling.patch
kill-vmalloc_earlyreserve.patch
x86-fix-change_page_attr-tlb-and-cache-flushing.patch
x86-smp-alt-once-option-is-only-useful-with-hotplug_cpu.patch
x86-64-remove-unused-variable-maxcpus.patch
-
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