diff options
author | Paul Jackson <pj@sgi.com> | 2005-09-07 00:18:13 +0200 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-08 01:57:40 +0200 |
commit | ef08e3b4981aebf2ba9bd7025ef7210e8eec07ce (patch) | |
tree | 3b5386e011c87dde384115c8eb0d6961c2536025 /kernel | |
parent | [PATCH] cpusets: formalize intermediate GFP_KERNEL containment (diff) | |
download | linux-ef08e3b4981aebf2ba9bd7025ef7210e8eec07ce.tar.xz linux-ef08e3b4981aebf2ba9bd7025ef7210e8eec07ce.zip |
[PATCH] cpusets: confine oom_killer to mem_exclusive cpuset
Now the real motivation for this cpuset mem_exclusive patch series seems
trivial.
This patch keeps a task in or under one mem_exclusive cpuset from provoking an
oom kill of a task under a non-overlapping mem_exclusive cpuset. Since only
interrupt and GFP_ATOMIC allocations are allowed to escape mem_exclusive
containment, there is little to gain from oom killing a task under a
non-overlapping mem_exclusive cpuset, as almost all kernel and user memory
allocation must come from disjoint memory nodes.
This patch enables configuring a system so that a runaway job under one
mem_exclusive cpuset cannot cause the killing of a job in another such cpuset
that might be using very high compute and memory resources for a prolonged
time.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/cpuset.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 214806deca99..40c6d801dd66 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1688,6 +1688,39 @@ done: return allowed; } +/** + * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors? + * @p: pointer to task_struct of some other task. + * + * Description: Return true if the nearest mem_exclusive ancestor + * cpusets of tasks @p and current overlap. Used by oom killer to + * determine if task @p's memory usage might impact the memory + * available to the current task. + * + * Acquires cpuset_sem - not suitable for calling from a fast path. + **/ + +int cpuset_excl_nodes_overlap(const struct task_struct *p) +{ + const struct cpuset *cs1, *cs2; /* my and p's cpuset ancestors */ + int overlap = 0; /* do cpusets overlap? */ + + down(&cpuset_sem); + cs1 = current->cpuset; + if (!cs1) + goto done; /* current task exiting */ + cs2 = p->cpuset; + if (!cs2) + goto done; /* task p is exiting */ + cs1 = nearest_exclusive_ancestor(cs1); + cs2 = nearest_exclusive_ancestor(cs2); + overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed); +done: + up(&cpuset_sem); + + return overlap; +} + /* * proc_cpuset_show() * - Print tasks cpuset path into seq_file. |