At 11/21/2012 06:25 AM, Andrew Morton Wrote: > On Fri, 16 Nov 2012 19:58:09 +0800 > Wen Congyang <wency@xxxxxxxxxxxxxx> wrote: > >> From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> >> >> All are prepared, we can actually introduce N_MEMORY. >> add CONFIG_MOVABLE_NODE make we can use it for movable-dedicated node > > This description is far too short on details. > > I grabbed this from the [0/n] email: > > : We need a node which only contains movable memory. This feature is very > : important for node hotplug. If a node has normal/highmem, the memory may > : be used by the kernel and can't be offlined. If the node only contains > : movable memory, we can offline the memory and the node. > > which helps a bit, but it's still pretty thin. > > Why is this option made configurable? Why not enable it unconditionally? > > Please send a patch which adds the Kconfig help text for > CONFIG_MOVABLE_NODE. Let's make that text nice and detailed. > > The name MOVABLE_NODE is not a good one. It means "a node which is > movable", whereas the concept is actually "a node whcih contains only > movable memory". I suppose we could change it to something like > CONFIG_MOVABLE_MEMORY_ONLY_NODE or similar. But I suppose that > CONFIG_MOVABLE_NODE is good enough, as long as it is well-described in > associated comments or help text. This is not the case at present. > >> +#ifdef CONFIG_MOVABLE_NODE >> + N_MEMORY, /* The node has memory(regular, high, movable) */ >> +#else > > I think the comment should be "The node has only movable memory"? No, the comment is right. In the kernel, we need the following two mask: 1. the node contains memory that the kernel can use(N_HIGH_MEMORY) 2. the node contains memory (N_MEMORY) There is no code need the mask: the node contains only movable memory now. Thanks Wen Congyang > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>