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Commit 078a1989 authored by Tejun Heo's avatar Tejun Heo
Browse files

x86-64, NUMA: Don't assume phys node 0 is always online in numa_emulation() 



Undetermined entries in emu_nid_to_phys[] are filled with zero
assuming that physical node 0 is always online; however, this might
not be true depending on hardware configuration.  Find a physical node
which is actually online and use it instead.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarDavid Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1103020628210.31626@chino.kir.corp.google.com>
parent c09cedf4

arch/x86/mm/numa_emulation.c

+15 −1
Original line number Diff line number Diff line
@@ -301,6 +301,7 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) 
	const u64 max_addr = max_pfn << PAGE_SHIFT;

	u8 *phys_dist = NULL;

	size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);

	int dfl_phys_nid;

	int i, j, ret;



	if (!emu_cmdline)
@@ -357,6 +358,19 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) 
					node_distance(i, j);

	}



	/* determine the default phys nid to use for unmapped nodes */

	dfl_phys_nid = NUMA_NO_NODE;

	for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {

		if (emu_nid_to_phys[i] != NUMA_NO_NODE) {

			dfl_phys_nid = emu_nid_to_phys[i];

			break;

		}

	}

	if (dfl_phys_nid == NUMA_NO_NODE) {

		pr_warning("NUMA: Warning: can't determine default physical node, disabling emulation\n");

		goto no_emu;

	}



	/* commit */

	*numa_meminfo = ei;
@@ -377,7 +391,7 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) 
	/* make sure all emulated nodes are mapped to a physical node */

	for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)

		if (emu_nid_to_phys[i] == NUMA_NO_NODE)

			emu_nid_to_phys[i] = 0;

			emu_nid_to_phys[i] = dfl_phys_nid;



	/*

	 * Transform distance table.  numa_set_distance() ignores all