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-rw-r--r--arch/x86/mm/numa.c67
1 files changed, 44 insertions, 23 deletions
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index d04f8094b..f70c1ff46 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -465,46 +465,67 @@ static bool __init numa_meminfo_cover_memory(const struct numa_meminfo *mi)
return true;
}
+/*
+ * Mark all currently memblock-reserved physical memory (which covers the
+ * kernel's own memory ranges) as hot-unswappable.
+ */
static void __init numa_clear_kernel_node_hotplug(void)
{
- int i, nid;
- nodemask_t numa_kernel_nodes = NODE_MASK_NONE;
- phys_addr_t start, end;
- struct memblock_region *r;
+ nodemask_t reserved_nodemask = NODE_MASK_NONE;
+ struct memblock_region *mb_region;
+ int i;
/*
+ * We have to do some preprocessing of memblock regions, to
+ * make them suitable for reservation.
+ *
* At this time, all memory regions reserved by memblock are
- * used by the kernel. Set the nid in memblock.reserved will
- * mark out all the nodes the kernel resides in.
+ * used by the kernel, but those regions are not split up
+ * along node boundaries yet, and don't necessarily have their
+ * node ID set yet either.
+ *
+ * So iterate over all memory known to the x86 architecture,
+ * and use those ranges to set the nid in memblock.reserved.
+ * This will split up the memblock regions along node
+ * boundaries and will set the node IDs as well.
*/
for (i = 0; i < numa_meminfo.nr_blks; i++) {
- struct numa_memblk *mb = &numa_meminfo.blk[i];
+ struct numa_memblk *mb = numa_meminfo.blk + i;
+ int ret;
- memblock_set_node(mb->start, mb->end - mb->start,
- &memblock.reserved, mb->nid);
+ ret = memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid);
+ WARN_ON_ONCE(ret);
}
/*
- * Mark all kernel nodes.
+ * Now go over all reserved memblock regions, to construct a
+ * node mask of all kernel reserved memory areas.
*
- * When booting with mem=nn[kMG] or in a kdump kernel, numa_meminfo
- * may not include all the memblock.reserved memory ranges because
- * trim_snb_memory() reserves specific pages for Sandy Bridge graphics.
+ * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
+ * numa_meminfo might not include all memblock.reserved
+ * memory ranges, because quirks such as trim_snb_memory()
+ * reserve specific pages for Sandy Bridge graphics. ]
*/
- for_each_memblock(reserved, r)
- if (r->nid != MAX_NUMNODES)
- node_set(r->nid, numa_kernel_nodes);
+ for_each_memblock(reserved, mb_region) {
+ if (mb_region->nid != MAX_NUMNODES)
+ node_set(mb_region->nid, reserved_nodemask);
+ }
- /* Clear MEMBLOCK_HOTPLUG flag for memory in kernel nodes. */
+ /*
+ * Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
+ * belonging to the reserved node mask.
+ *
+ * Note that this will include memory regions that reside
+ * on nodes that contain kernel memory - entire nodes
+ * become hot-unpluggable:
+ */
for (i = 0; i < numa_meminfo.nr_blks; i++) {
- nid = numa_meminfo.blk[i].nid;
- if (!node_isset(nid, numa_kernel_nodes))
- continue;
+ struct numa_memblk *mb = numa_meminfo.blk + i;
- start = numa_meminfo.blk[i].start;
- end = numa_meminfo.blk[i].end;
+ if (!node_isset(mb->nid, reserved_nodemask))
+ continue;
- memblock_clear_hotplug(start, end - start);
+ memblock_clear_hotplug(mb->start, mb->end - mb->start);
}
}