The cpu<->node mappings under CONFIG_DEBUG_PER_CPU_MAPS=y
when NUMA emulation is enabled is currently broken because it does
not iterate through every emulated node and bind cpus that have
affinity to it.
NUMA emulation should bind each cpu to every local node to
accurately represent the true NUMA topology of the underlying
machine.
debug_cpumask_set_cpu() needs to be fixed at the same time so
that the debugging information that it emits shows the new
cpumask of the node being assigned when the cpu is being added
or removed.
It can now take responsibility of setting or clearing the cpu
itself to remove the need for duplicate code.
Also change its last parameter, "enable", to have the correct bool
type since it can only be true or false.
-v2: Fix the return statements, by Kosaki Motohiro
Acked-and-Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Andreas Herrmann <herrmann.der.user@googlemail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1104201918470.12634@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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 <tj@kernel.org>
Reported-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Yinghai Lu <yinghai@kernel.org>
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: Tejun Heo <tj@kernel.org>
Reported-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1103020628210.31626@chino.kir.corp.google.com>
Handling of out-of-bounds distances and allocation failure can use
better documentation. Add it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
NUMA distance table handling has the following problems.
* numa_reset_distance() uses numa_distance * sizeof(numa_distance[0])
as the table size when it should be using the square of
numa_distance.
* The same size miscalculation when allocation space for phys_dist in
numa_emulation().
* In numa_emulation(), phys_dist must be reserved; otherwise, the new
emulated distance table may overlap it.
Fix them and, while at it, take numa_distance_cnt resetting in
numa_reset_distance() out of the if block to simplify the code a bit.
David Rientjes reported incorrect handling of distance table during
emulation.
-tj: Edited out numa_alloc_distance() related changes which weren't
necessary and rewrote patch description.
-v2: Ingo was unhappy with 80-column limit induced linebreaks. Let
lines run over 80-column.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reported-by: David Rientjes <rientjes@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: David Rientjes <rientjes@google.com>
Create numa_emulation.c and move all NUMA emulation code there. The
definitions of struct numa_memblk and numa_meminfo are moved to
numa_64.h. Also, numa_remove_memblk_from(), numa_cleanup_meminfo(),
numa_reset_distance() along with numa_emulation() are made global.
- v2: Internal declarations moved to numa_internal.h as suggested by
Yinghai.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
