sched: Refactor task_struct to use numa_faults instead of numa_* pointers
This patch simplifies task_struct by removing the four numa_* pointers in the same array and replacing them with the array pointer. By doing this, on x86_64, the size of task_struct is reduced by 3 ulong pointers (24 bytes on x86_64). A new parameter is added to the task_faults_idx function so that it can return an index to the correct offset, corresponding with the old precalculated pointers. All of the code in sched/ that depended on task_faults_idx and numa_* was changed in order to match the new logic. Signed-off-by: Iulia Manda <iulia.manda21@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: mgorman@suse.de Cc: dave@stgolabs.net Cc: riel@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20141031001331.GA30662@winterfell Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Iulia Manda
Ingo Molnar
parent
cad3bb32e1
commit
44dba3d5d6
@ -1597,27 +1597,22 @@ struct task_struct {
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struct numa_group *numa_group;
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/*
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* Exponential decaying average of faults on a per-node basis.
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* Scheduling placement decisions are made based on the these counts.
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* The values remain static for the duration of a PTE scan
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* numa_faults is an array split into four regions:
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* faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
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* in this precise order.
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*
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* faults_memory: Exponential decaying average of faults on a per-node
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* basis. Scheduling placement decisions are made based on these
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* counts. The values remain static for the duration of a PTE scan.
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* faults_cpu: Track the nodes the process was running on when a NUMA
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* hinting fault was incurred.
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* faults_memory_buffer and faults_cpu_buffer: Record faults per node
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* during the current scan window. When the scan completes, the counts
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* in faults_memory and faults_cpu decay and these values are copied.
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*/
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unsigned long *numa_faults_memory;
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unsigned long *numa_faults;
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unsigned long total_numa_faults;
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/*
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* numa_faults_buffer records faults per node during the current
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* scan window. When the scan completes, the counts in
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* numa_faults_memory decay and these values are copied.
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*/
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unsigned long *numa_faults_buffer_memory;
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/*
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* Track the nodes the process was running on when a NUMA hinting
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* fault was incurred.
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*/
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unsigned long *numa_faults_cpu;
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unsigned long *numa_faults_buffer_cpu;
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/*
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* numa_faults_locality tracks if faults recorded during the last
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* scan window were remote/local. The task scan period is adapted
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@ -1857,8 +1857,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
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p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;
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p->numa_scan_period = sysctl_numa_balancing_scan_delay;
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p->numa_work.next = &p->numa_work;
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p->numa_faults_memory = NULL;
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p->numa_faults_buffer_memory = NULL;
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p->numa_faults = NULL;
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p->last_task_numa_placement = 0;
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p->last_sum_exec_runtime = 0;
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@ -535,8 +535,8 @@ static void sched_show_numa(struct task_struct *p, struct seq_file *m)
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unsigned long nr_faults = -1;
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int cpu_current, home_node;
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if (p->numa_faults_memory)
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nr_faults = p->numa_faults_memory[2*node + i];
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if (p->numa_faults)
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nr_faults = p->numa_faults[2*node + i];
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cpu_current = !i ? (task_node(p) == node) :
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(pol && node_isset(node, pol->v.nodes));
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@ -896,18 +896,24 @@ pid_t task_numa_group_id(struct task_struct *p)
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return p->numa_group ? p->numa_group->gid : 0;
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}
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static inline int task_faults_idx(int nid, int priv)
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/*
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* The averaged statistics, shared & private, memory & cpu,
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* occupy the first half of the array. The second half of the
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* array is for current counters, which are averaged into the
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* first set by task_numa_placement.
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*/
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static inline int task_faults_idx(enum numa_faults_stats s, int nid, int priv)
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{
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return NR_NUMA_HINT_FAULT_TYPES * nid + priv;
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return NR_NUMA_HINT_FAULT_TYPES * (s * nr_node_ids + nid) + priv;
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}
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static inline unsigned long task_faults(struct task_struct *p, int nid)
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{
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if (!p->numa_faults_memory)
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if (!p->numa_faults)
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return 0;
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return p->numa_faults_memory[task_faults_idx(nid, 0)] +
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p->numa_faults_memory[task_faults_idx(nid, 1)];
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return p->numa_faults[task_faults_idx(NUMA_MEM, nid, 0)] +
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p->numa_faults[task_faults_idx(NUMA_MEM, nid, 1)];
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}
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static inline unsigned long group_faults(struct task_struct *p, int nid)
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@ -915,14 +921,14 @@ static inline unsigned long group_faults(struct task_struct *p, int nid)
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if (!p->numa_group)
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return 0;
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return p->numa_group->faults[task_faults_idx(nid, 0)] +
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p->numa_group->faults[task_faults_idx(nid, 1)];
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return p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 0)] +
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p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 1)];
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}
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static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
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{
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return group->faults_cpu[task_faults_idx(nid, 0)] +
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group->faults_cpu[task_faults_idx(nid, 1)];
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return group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 0)] +
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group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 1)];
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}
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/* Handle placement on systems where not all nodes are directly connected. */
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@ -1001,7 +1007,7 @@ static inline unsigned long task_weight(struct task_struct *p, int nid,
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{
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unsigned long faults, total_faults;
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if (!p->numa_faults_memory)
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if (!p->numa_faults)
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return 0;
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total_faults = p->total_numa_faults;
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@ -1517,7 +1523,7 @@ static void numa_migrate_preferred(struct task_struct *p)
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unsigned long interval = HZ;
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/* This task has no NUMA fault statistics yet */
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if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults_memory))
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if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults))
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return;
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/* Periodically retry migrating the task to the preferred node */
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@ -1779,18 +1785,23 @@ static void task_numa_placement(struct task_struct *p)
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/* Find the node with the highest number of faults */
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for_each_online_node(nid) {
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/* Keep track of the offsets in numa_faults array */
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int mem_idx, membuf_idx, cpu_idx, cpubuf_idx;
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unsigned long faults = 0, group_faults = 0;
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int priv, i;
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int priv;
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for (priv = 0; priv < NR_NUMA_HINT_FAULT_TYPES; priv++) {
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long diff, f_diff, f_weight;
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i = task_faults_idx(nid, priv);
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mem_idx = task_faults_idx(NUMA_MEM, nid, priv);
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membuf_idx = task_faults_idx(NUMA_MEMBUF, nid, priv);
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cpu_idx = task_faults_idx(NUMA_CPU, nid, priv);
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cpubuf_idx = task_faults_idx(NUMA_CPUBUF, nid, priv);
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/* Decay existing window, copy faults since last scan */
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diff = p->numa_faults_buffer_memory[i] - p->numa_faults_memory[i] / 2;
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fault_types[priv] += p->numa_faults_buffer_memory[i];
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p->numa_faults_buffer_memory[i] = 0;
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diff = p->numa_faults[membuf_idx] - p->numa_faults[mem_idx] / 2;
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fault_types[priv] += p->numa_faults[membuf_idx];
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p->numa_faults[membuf_idx] = 0;
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/*
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* Normalize the faults_from, so all tasks in a group
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@ -1800,21 +1811,27 @@ static void task_numa_placement(struct task_struct *p)
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* faults are less important.
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*/
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f_weight = div64_u64(runtime << 16, period + 1);
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f_weight = (f_weight * p->numa_faults_buffer_cpu[i]) /
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f_weight = (f_weight * p->numa_faults[cpubuf_idx]) /
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(total_faults + 1);
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f_diff = f_weight - p->numa_faults_cpu[i] / 2;
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p->numa_faults_buffer_cpu[i] = 0;
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f_diff = f_weight - p->numa_faults[cpu_idx] / 2;
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p->numa_faults[cpubuf_idx] = 0;
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p->numa_faults_memory[i] += diff;
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p->numa_faults_cpu[i] += f_diff;
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faults += p->numa_faults_memory[i];
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p->numa_faults[mem_idx] += diff;
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p->numa_faults[cpu_idx] += f_diff;
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faults += p->numa_faults[mem_idx];
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p->total_numa_faults += diff;
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if (p->numa_group) {
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/* safe because we can only change our own group */
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p->numa_group->faults[i] += diff;
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p->numa_group->faults_cpu[i] += f_diff;
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/*
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* safe because we can only change our own group
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*
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* mem_idx represents the offset for a given
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* nid and priv in a specific region because it
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* is at the beginning of the numa_faults array.
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*/
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p->numa_group->faults[mem_idx] += diff;
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p->numa_group->faults_cpu[mem_idx] += f_diff;
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p->numa_group->total_faults += diff;
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group_faults += p->numa_group->faults[i];
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group_faults += p->numa_group->faults[mem_idx];
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}
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}
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@ -1886,7 +1903,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
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node_set(task_node(current), grp->active_nodes);
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for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
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grp->faults[i] = p->numa_faults_memory[i];
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grp->faults[i] = p->numa_faults[i];
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grp->total_faults = p->total_numa_faults;
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@ -1945,8 +1962,8 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
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double_lock_irq(&my_grp->lock, &grp->lock);
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for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) {
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my_grp->faults[i] -= p->numa_faults_memory[i];
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grp->faults[i] += p->numa_faults_memory[i];
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my_grp->faults[i] -= p->numa_faults[i];
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grp->faults[i] += p->numa_faults[i];
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}
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my_grp->total_faults -= p->total_numa_faults;
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grp->total_faults += p->total_numa_faults;
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@ -1971,14 +1988,14 @@ no_join:
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void task_numa_free(struct task_struct *p)
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{
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struct numa_group *grp = p->numa_group;
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void *numa_faults = p->numa_faults_memory;
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void *numa_faults = p->numa_faults;
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unsigned long flags;
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int i;
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if (grp) {
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spin_lock_irqsave(&grp->lock, flags);
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for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
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grp->faults[i] -= p->numa_faults_memory[i];
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grp->faults[i] -= p->numa_faults[i];
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grp->total_faults -= p->total_numa_faults;
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list_del(&p->numa_entry);
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@ -1988,10 +2005,7 @@ void task_numa_free(struct task_struct *p)
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put_numa_group(grp);
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}
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p->numa_faults_memory = NULL;
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p->numa_faults_buffer_memory = NULL;
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p->numa_faults_cpu= NULL;
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p->numa_faults_buffer_cpu = NULL;
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p->numa_faults = NULL;
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kfree(numa_faults);
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}
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@ -2014,24 +2028,14 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
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return;
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/* Allocate buffer to track faults on a per-node basis */
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if (unlikely(!p->numa_faults_memory)) {
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int size = sizeof(*p->numa_faults_memory) *
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if (unlikely(!p->numa_faults)) {
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int size = sizeof(*p->numa_faults) *
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NR_NUMA_HINT_FAULT_BUCKETS * nr_node_ids;
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p->numa_faults_memory = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
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if (!p->numa_faults_memory)
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p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
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if (!p->numa_faults)
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return;
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BUG_ON(p->numa_faults_buffer_memory);
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/*
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* The averaged statistics, shared & private, memory & cpu,
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* occupy the first half of the array. The second half of the
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* array is for current counters, which are averaged into the
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* first set by task_numa_placement.
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*/
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p->numa_faults_cpu = p->numa_faults_memory + (2 * nr_node_ids);
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p->numa_faults_buffer_memory = p->numa_faults_memory + (4 * nr_node_ids);
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p->numa_faults_buffer_cpu = p->numa_faults_memory + (6 * nr_node_ids);
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p->total_numa_faults = 0;
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memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
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}
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@ -2071,8 +2075,8 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
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if (migrated)
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p->numa_pages_migrated += pages;
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p->numa_faults_buffer_memory[task_faults_idx(mem_node, priv)] += pages;
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p->numa_faults_buffer_cpu[task_faults_idx(cpu_node, priv)] += pages;
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p->numa_faults[task_faults_idx(NUMA_MEMBUF, mem_node, priv)] += pages;
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p->numa_faults[task_faults_idx(NUMA_CPUBUF, cpu_node, priv)] += pages;
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p->numa_faults_locality[local] += pages;
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}
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@ -5361,7 +5365,7 @@ static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env)
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struct numa_group *numa_group = rcu_dereference(p->numa_group);
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int src_nid, dst_nid;
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if (!sched_feat(NUMA_FAVOUR_HIGHER) || !p->numa_faults_memory ||
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if (!sched_feat(NUMA_FAVOUR_HIGHER) || !p->numa_faults ||
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!(env->sd->flags & SD_NUMA)) {
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return false;
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}
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@ -5400,7 +5404,7 @@ static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
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if (!sched_feat(NUMA) || !sched_feat(NUMA_RESIST_LOWER))
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return false;
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if (!p->numa_faults_memory || !(env->sd->flags & SD_NUMA))
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if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
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return false;
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src_nid = cpu_to_node(env->src_cpu);
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@ -709,6 +709,13 @@ extern bool find_numa_distance(int distance);
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#endif
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#ifdef CONFIG_NUMA_BALANCING
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/* The regions in numa_faults array from task_struct */
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enum numa_faults_stats {
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NUMA_MEM = 0,
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NUMA_CPU,
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NUMA_MEMBUF,
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NUMA_CPUBUF
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};
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extern void sched_setnuma(struct task_struct *p, int node);
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extern int migrate_task_to(struct task_struct *p, int cpu);
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extern int migrate_swap(struct task_struct *, struct task_struct *);
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