mm: numa: Change page last {nid,pid} into {cpu,pid}

Change the per page last fault tracking to use cpu,pid instead of
nid,pid. This will allow us to try and lookup the alternate task more
easily. Note that even though it is the cpu that is store in the page
flags that the mpol_misplaced decision is still based on the node.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1381141781-10992-43-git-send-email-mgorman@suse.de
[ Fixed build failure on 32-bit systems. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 9 insertions, 7 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 0e895a2eed5f..a5867ef24bda 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2324,6 +2324,8 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
         struct zone *zone;
         int curnid = page_to_nid(page);
         unsigned long pgoff;
+        int thiscpu = raw_smp_processor_id();
+        int thisnid = cpu_to_node(thiscpu);
         int polnid = -1;
         int ret = -1;
 
@@ -2372,11 +2374,11 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
 
         /* Migrate the page towards the node whose CPU is referencing it */
         if (pol->flags & MPOL_F_MORON) {
-                int last_nidpid;
-                int this_nidpid;
+                int last_cpupid;
+                int this_cpupid;
 
-                polnid = numa_node_id();
-                this_nidpid = nid_pid_to_nidpid(polnid, current->pid);
+                polnid = thisnid;
+                this_cpupid = cpu_pid_to_cpupid(thiscpu, current->pid);
 
                 /*
                  * Multi-stage node selection is used in conjunction
@@ -2399,8 +2401,8 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
                  * it less likely we act on an unlikely task<->page
                  * relation.
                  */
-                last_nidpid = page_nidpid_xchg_last(page, this_nidpid);
-                if (!nidpid_pid_unset(last_nidpid) && nidpid_to_nid(last_nidpid) != polnid)
+                last_cpupid = page_cpupid_xchg_last(page, this_cpupid);
+                if (!cpupid_pid_unset(last_cpupid) && cpupid_to_nid(last_cpupid) != thisnid)
                         goto out;
 
 #ifdef CONFIG_NUMA_BALANCING
@@ -2410,7 +2412,7 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
                  * This way a short and temporary process migration will
                  * not cause excessive memory migration.
                  */
-                if (polnid != current->numa_preferred_nid &&
+                if (thisnid != current->numa_preferred_nid &&
                                 !current->numa_migrate_seq)
                         goto out;
 #endif