forked from Minki/linux
Memoryless nodes: Use N_HIGH_MEMORY for cpusets
cpusets try to ensure that any node added to a cpuset's mems_allowed is on-line and contains memory. The assumption was that online nodes contained memory. Thus, it is possible to add memoryless nodes to a cpuset and then add tasks to this cpuset. This results in continuous series of oom-kill and apparent system hang. Change cpusets to use node_states[N_HIGH_MEMORY] [a.k.a. node_memory_map] in place of node_online_map when vetting memories. Return error if admin attempts to write a non-empty mems_allowed node mask containing only memoryless-nodes. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@skynet.ie> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Lameter
Linus Torvalds
parent
523b945855
commit
0e1e7c7a73
@ -35,7 +35,8 @@ CONTENTS:
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----------------------
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Cpusets provide a mechanism for assigning a set of CPUs and Memory
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Nodes to a set of tasks.
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Nodes to a set of tasks. In this document "Memory Node" refers to
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an on-line node that contains memory.
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Cpusets constrain the CPU and Memory placement of tasks to only
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the resources within a tasks current cpuset. They form a nested
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@ -220,8 +221,8 @@ and name space for cpusets, with a minimum of additional kernel code.
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The cpus and mems files in the root (top_cpuset) cpuset are
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read-only. The cpus file automatically tracks the value of
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cpu_online_map using a CPU hotplug notifier, and the mems file
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automatically tracks the value of node_online_map using the
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cpuset_track_online_nodes() hook.
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automatically tracks the value of node_states[N_MEMORY]--i.e.,
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nodes with memory--using the cpuset_track_online_nodes() hook.
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1.4 What are exclusive cpusets ?
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@ -93,7 +93,7 @@ static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
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return node_possible_map;
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}
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#define cpuset_current_mems_allowed (node_online_map)
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#define cpuset_current_mems_allowed (node_states[N_HIGH_MEMORY])
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static inline void cpuset_init_current_mems_allowed(void) {}
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static inline void cpuset_update_task_memory_state(void) {}
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#define cpuset_nodes_subset_current_mems_allowed(nodes) (1)
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@ -581,26 +581,28 @@ static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
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/*
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* Return in *pmask the portion of a cpusets's mems_allowed that
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* are online. If none are online, walk up the cpuset hierarchy
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* until we find one that does have some online mems. If we get
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* all the way to the top and still haven't found any online mems,
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* return node_online_map.
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* are online, with memory. If none are online with memory, walk
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* up the cpuset hierarchy until we find one that does have some
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* online mems. If we get all the way to the top and still haven't
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* found any online mems, return node_states[N_HIGH_MEMORY].
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*
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* One way or another, we guarantee to return some non-empty subset
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* of node_online_map.
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* of node_states[N_HIGH_MEMORY].
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*
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* Call with callback_mutex held.
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*/
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static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
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{
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while (cs && !nodes_intersects(cs->mems_allowed, node_online_map))
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while (cs && !nodes_intersects(cs->mems_allowed,
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node_states[N_HIGH_MEMORY]))
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cs = cs->parent;
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if (cs)
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nodes_and(*pmask, cs->mems_allowed, node_online_map);
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nodes_and(*pmask, cs->mems_allowed,
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node_states[N_HIGH_MEMORY]);
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else
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*pmask = node_online_map;
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BUG_ON(!nodes_intersects(*pmask, node_online_map));
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*pmask = node_states[N_HIGH_MEMORY];
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BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY]));
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}
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/**
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@ -924,7 +926,10 @@ static int update_nodemask(struct cpuset *cs, char *buf)
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int fudge;
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int retval;
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/* top_cpuset.mems_allowed tracks node_online_map; it's read-only */
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/*
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* top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
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* it's read-only
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*/
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if (cs == &top_cpuset)
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return -EACCES;
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@ -941,8 +946,21 @@ static int update_nodemask(struct cpuset *cs, char *buf)
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retval = nodelist_parse(buf, trialcs.mems_allowed);
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if (retval < 0)
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goto done;
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if (!nodes_intersects(trialcs.mems_allowed,
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node_states[N_HIGH_MEMORY])) {
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/*
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* error if only memoryless nodes specified.
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*/
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retval = -ENOSPC;
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goto done;
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}
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}
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nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map);
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/*
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* Exclude memoryless nodes. We know that trialcs.mems_allowed
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* contains at least one node with memory.
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*/
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nodes_and(trialcs.mems_allowed, trialcs.mems_allowed,
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node_states[N_HIGH_MEMORY]);
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oldmem = cs->mems_allowed;
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if (nodes_equal(oldmem, trialcs.mems_allowed)) {
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retval = 0; /* Too easy - nothing to do */
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@ -2098,8 +2116,9 @@ static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur)
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/*
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* The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
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* cpu_online_map and node_online_map. Force the top cpuset to track
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* whats online after any CPU or memory node hotplug or unplug event.
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* cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to
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* track what's online after any CPU or memory node hotplug or unplug
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* event.
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*
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* To ensure that we don't remove a CPU or node from the top cpuset
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* that is currently in use by a child cpuset (which would violate
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@ -2119,7 +2138,7 @@ static void common_cpu_mem_hotplug_unplug(void)
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guarantee_online_cpus_mems_in_subtree(&top_cpuset);
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top_cpuset.cpus_allowed = cpu_online_map;
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top_cpuset.mems_allowed = node_online_map;
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top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
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mutex_unlock(&callback_mutex);
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mutex_unlock(&manage_mutex);
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@ -2147,8 +2166,9 @@ static int cpuset_handle_cpuhp(struct notifier_block *nb,
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#ifdef CONFIG_MEMORY_HOTPLUG
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/*
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* Keep top_cpuset.mems_allowed tracking node_online_map.
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* Call this routine anytime after you change node_online_map.
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* Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY].
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* Call this routine anytime after you change
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* node_states[N_HIGH_MEMORY].
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* See also the previous routine cpuset_handle_cpuhp().
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*/
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@ -2167,7 +2187,7 @@ void cpuset_track_online_nodes(void)
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void __init cpuset_init_smp(void)
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{
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top_cpuset.cpus_allowed = cpu_online_map;
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top_cpuset.mems_allowed = node_online_map;
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top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
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hotcpu_notifier(cpuset_handle_cpuhp, 0);
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}
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@ -2309,7 +2329,7 @@ void cpuset_init_current_mems_allowed(void)
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*
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* Description: Returns the nodemask_t mems_allowed of the cpuset
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* attached to the specified @tsk. Guaranteed to return some non-empty
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* subset of node_online_map, even if this means going outside the
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* subset of node_states[N_HIGH_MEMORY], even if this means going outside the
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* tasks cpuset.
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**/
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