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author | John Hawkes <hawkes@sgi.com> | 2005-09-07 00:18:06 +0200 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-08 01:57:39 +0200 |
commit | f68f447e8389de9a62e3e80c3c5823cce484c2e5 (patch) | |
tree | 218ec8e11ecbfc730e248b3dae7ebbbe9fdc5da6 /mm/oom_kill.c | |
parent | [PATCH] block: CFQ refcounting fix (diff) | |
download | linux-f68f447e8389de9a62e3e80c3c5823cce484c2e5.tar.xz linux-f68f447e8389de9a62e3e80c3c5823cce484c2e5.zip |
[PATCH] ia64 cpuset + build_sched_domains() mangles structures
I've already sent this to the maintainers, and this is now being sent to a
larger community audience. I have fixed a problem with the ia64 version of
build_sched_domains(), but a similar fix still needs to be made to the
generic build_sched_domains() in kernel/sched.c.
The "dynamic sched domains" functionality has recently been merged into
2.6.13-rcN that sees the dynamic declaration of a cpu-exclusive (a.k.a.
"isolated") cpuset and rebuilds the CPU Scheduler sched domains and sched
groups to separate away the CPUs in this cpu-exclusive cpuset from the
remainder of the non-isolated CPUs. This allows the non-isolated CPUs to
completely ignore the isolated CPUs when doing load-balancing.
Unfortunately, build_sched_domains() expects that a sched domain will
include all the CPUs of each node in the domain, i.e., that no node will
belong in both an isolated cpuset and a non-isolated cpuset. Declaring a
cpuset that violates this presumption will produce flawed data structures
and will oops the kernel.
To trigger the problem (on a NUMA system with >1 CPUs per node):
cd /dev/cpuset
mkdir newcpuset
cd newcpuset
echo 0 >cpus
echo 0 >mems
echo 1 >cpu_exclusive
I have fixed this shortcoming for ia64 NUMA (with multiple CPUs per node).
A similar shortcoming exists in the generic build_sched_domains() (in
kernel/sched.c) for NUMA, and that needs to be fixed also. The fix
involves dynamically allocating sched_group_nodes[] and
sched_group_allnodes[] for each invocation of build_sched_domains(), rather
than using global arrays for these structures. Care must be taken to
remember kmalloc() addresses so that arch_destroy_sched_domains() can
properly kfree() the new dynamic structures.
Signed-off-by: John Hawkes <hawkes@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/oom_kill.c')
0 files changed, 0 insertions, 0 deletions