sched/numa: Call task_numa_free() from do_execve()

It is possible for a task in a numa group to call exec, and
have the new (unrelated) executable inherit the numa group
association from its former self.

This has the potential to break numa grouping, and is trivial
to fix.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-51-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/fs/exec.c b/fs/exec.c
index 8875dd10ae7ac77444db95e33c9fde83dde67512..2ea437e5acf4d9b0064b48c900d3fa1597573e3b 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1547,6 +1547,7 @@ static int do_execve_common(const char *filename,
        current->fs->in_exec = 0;
        current->in_execve = 0;
        acct_update_integrals(current);
+       task_numa_free(current);
        free_bprm(bprm);
        if (displaced)
                put_files_struct(displaced);

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 724482200b83e640667cc7a392bda015ef05b72d..f6385107c35243d9eecbce5861572b7fd4c1e103 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1458,6 +1458,7 @@ struct task_struct {
 extern void task_numa_fault(int last_node, int node, int pages, int flags);
 extern pid_t task_numa_group_id(struct task_struct *p);
 extern void set_numabalancing_state(bool enabled);
+extern void task_numa_free(struct task_struct *p);
 #else
 static inline void task_numa_fault(int last_node, int node, int pages,
                                   int flags)
@@ -1470,6 +1471,9 @@ static inline pid_t task_numa_group_id(struct task_struct *p)
 static inline void set_numabalancing_state(bool enabled)
 {
 }
+static inline void task_numa_free(struct task_struct *p)
+{
+}
 #endif
 
 static inline struct pid *task_pid(struct task_struct *task)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 4c40e13310e9527534da84a6d3e46b357db3ea4e..c4df2de6ca4a75b1905bfb9718a3ae2991e87bee 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1418,6 +1418,7 @@ void task_numa_free(struct task_struct *p)
 {
        struct numa_group *grp = p->numa_group;
        int i;
+       void *numa_faults = p->numa_faults;
 
        if (grp) {
                for (i = 0; i < 2*nr_node_ids; i++)
@@ -1433,7 +1434,9 @@ void task_numa_free(struct task_struct *p)
                put_numa_group(grp);
        }
 
-       kfree(p->numa_faults);
+       p->numa_faults = NULL;
+       p->numa_faults_buffer = NULL;
+       kfree(numa_faults);
 }
 
 /*
@@ -1452,6 +1455,10 @@ void task_numa_fault(int last_cpupid, int node, int pages, int flags)
        if (!p->mm)
                return;
 
+       /* Do not worry about placement if exiting */
+       if (p->state == TASK_DEAD)
+               return;
+
        /* Allocate buffer to track faults on a per-node basis */
        if (unlikely(!p->numa_faults)) {
                int size = sizeof(*p->numa_faults) * 2 * nr_node_ids;

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 8037b10a256f2d1619fc3cfe3861197c8b52e128..eeb1923812a1285c89288de76d1115dac84ba83f 100644 (file)
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -559,11 +559,6 @@ static inline u64 rq_clock_task(struct rq *rq)
 #ifdef CONFIG_NUMA_BALANCING
 extern int migrate_task_to(struct task_struct *p, int cpu);
 extern int migrate_swap(struct task_struct *, struct task_struct *);
-extern void task_numa_free(struct task_struct *p);
-#else /* CONFIG_NUMA_BALANCING */
-static inline void task_numa_free(struct task_struct *p)
-{
-}
 #endif /* CONFIG_NUMA_BALANCING */
 
 #ifdef CONFIG_SMP