memory_hotplug: introduce memhp_default_state= command line parameter (86dd995d) · Commits · 戴 / test

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>

Documentation/kernel-parameters.txt

+8 −0

Original line number	Diff line number	Diff line
		@@ -2161,6 +2161,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
		[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

mm/memory_hotplug.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -85,6 +85,17 @@ bool memhp_auto_online = true;
		#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();

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