memory_hotplug: introduce memhp_default_state= command line parameter
CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE specifies the default value for the
memory hotplug onlining policy. Add a command line parameter to make it
possible to override the default. It may come handy for debug and
testing purposes.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7944031..2edb27b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2161,6 +2161,14 @@
[KNL,SH] Allow user to override the default size for
per-device physically contiguous DMA buffers.
+ memhp_default_state=online/offline
+ [KNL] Set the initial state for the memory hotplug
+ onlining policy. If not specified, the default value is
+ set according to the
+ CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel config
+ option.
+ See Documentation/memory-hotplug.txt.
+
memmap=exactmap [KNL,X86] Enable setting of an exact
E820 memory map, as specified by the user.
Such memmap=exactmap lines can be constructed based on
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index fcafbfc..caf2a14 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -85,6 +85,17 @@
#endif
EXPORT_SYMBOL_GPL(memhp_auto_online);
+static int __init setup_memhp_default_state(char *str)
+{
+ if (!strcmp(str, "online"))
+ memhp_auto_online = true;
+ else if (!strcmp(str, "offline"))
+ memhp_auto_online = false;
+
+ return 1;
+}
+__setup("memhp_default_state=", setup_memhp_default_state);
+
void get_online_mems(void)
{
might_sleep();