mm: numa: Add fault driven placement and migration
NOTE: This patch is based on "sched, numa, mm: Add fault driven
placement and migration policy" but as it throws away all the policy
to just leave a basic foundation I had to drop the signed-offs-by.
This patch creates a bare-bones method for setting PTEs pte_numa in the
context of the scheduler that when faulted later will be faulted onto the
node the CPU is running on. In itself this does nothing useful but any
placement policy will fundamentally depend on receiving hints on placement
from fault context and doing something intelligent about it.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
diff --git a/mm/memory.c b/mm/memory.c
index d525426..8012c19 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3454,7 +3454,8 @@
{
struct page *page = NULL;
spinlock_t *ptl;
- int current_nid, target_nid;
+ int current_nid = -1;
+ int target_nid;
/*
* The "pte" at this point cannot be used safely without
@@ -3501,6 +3502,7 @@
current_nid = target_nid;
out:
+ task_numa_fault(current_nid, 1);
return 0;
}
@@ -3537,6 +3539,7 @@
for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) {
pte_t pteval = *pte;
struct page *page;
+ int curr_nid;
if (!pte_present(pteval))
continue;
if (!pte_numa(pteval))
@@ -3554,6 +3557,15 @@
page = vm_normal_page(vma, addr, pteval);
if (unlikely(!page))
continue;
+ /* only check non-shared pages */
+ if (unlikely(page_mapcount(page) != 1))
+ continue;
+ pte_unmap_unlock(pte, ptl);
+
+ curr_nid = page_to_nid(page);
+ task_numa_fault(curr_nid, 1);
+
+ pte = pte_offset_map_lock(mm, pmdp, addr, &ptl);
}
pte_unmap_unlock(orig_pte, ptl);