From 56396e6823fe9b42fe9cf9403d6ed67756255f70 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 11 Mar 2011 10:33:31 +0100 Subject: x86-64, NUMA: Don't call numa_set_distanc() for all possible node combinations during emulation The distance transforming in numa_emulation() used to call numa_set_distance() for all MAX_NUMNODES * MAX_NUMNODES node combinations regardless of which are enabled. As numa_set_distance() ignores all out-of-bound distance settings, this doesn't cause any problem other than looping unnecessarily many times during boot. However, as MAX_NUMNODES * MAX_NUMNODES can be pretty high, update the code such that it iterates through only the enabled combinations. Yinghai Lu identified the issue and provided an initial patch to address the issue; however, the patch was incorrect in that it didn't build emulated distance table when there's no physical distance table and unnecessarily complex. http://thread.gmane.org/gmane.linux.kernel/1107986/focus=1107988 Signed-off-by: Tejun Heo Reported-by: Yinghai Lu Acked-by: Yinghai Lu --- arch/x86/mm/numa_emulation.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c index 3696be0c2204..ad091e4cff17 100644 --- a/arch/x86/mm/numa_emulation.c +++ b/arch/x86/mm/numa_emulation.c @@ -301,7 +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 max_emu_nid, dfl_phys_nid; int i, j, ret; if (!emu_cmdline) @@ -358,12 +358,17 @@ 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 */ + /* + * Determine the max emulated nid and the default phys nid to use + * for unmapped nodes. + */ + max_emu_nid = 0; 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; + max_emu_nid = i; + if (dfl_phys_nid == NUMA_NO_NODE) + dfl_phys_nid = emu_nid_to_phys[i]; } } if (dfl_phys_nid == NUMA_NO_NODE) { @@ -393,14 +398,10 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) if (emu_nid_to_phys[i] == NUMA_NO_NODE) emu_nid_to_phys[i] = dfl_phys_nid; - /* - * Transform distance table. numa_set_distance() ignores all - * out-of-bound distances. Just call it for every possible node - * combination. - */ + /* transform distance table */ numa_reset_distance(); - for (i = 0; i < MAX_NUMNODES; i++) { - for (j = 0; j < MAX_NUMNODES; j++) { + for (i = 0; i < max_emu_nid + 1; i++) { + for (j = 0; j < max_emu_nid + 1; j++) { int physi = emu_nid_to_phys[i]; int physj = emu_nid_to_phys[j]; int dist; -- cgit v1.2.3