[PATCH V2 1/6] Add check to match numa node id when gathering pte stats

[Prakash Sangappa]

Add support to check if numa node id matches when gathering pte stats,
to be used by later patches.

Signed-off-by: Prakash Sangappa <prakash.sanga...@oracle.com>
Reviewed-by: Steve Sistare <steven.sist...@oracle.com>
---
 fs/proc/task_mmu.c | 44 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 37 insertions(+), 7 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 5ea1d64..0e2095c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1569,9 +1569,15 @@ struct numa_maps {
        unsigned long mapcount_max;
        unsigned long dirty;
        unsigned long swapcache;
+        unsigned long nextaddr;
+                long nid;
+                long isvamaps;
        unsigned long node[MAX_NUMNODES];
 };
 
+#define        NUMA_VAMAPS_NID_NOPAGES         (-1)
+#define        NUMA_VAMAPS_NID_NONE    (-2)
+
 struct numa_maps_private {
        struct proc_maps_private proc_maps;
        struct numa_maps md;
@@ -1653,6 +1659,20 @@ static struct page *can_gather_numa_stats_pmd(pmd_t pmd,
 }
 #endif
 
+static bool
+vamap_match_nid(struct numa_maps *md, unsigned long addr, struct page *page)
+{
+       long target = (page ? page_to_nid(page) : NUMA_VAMAPS_NID_NOPAGES);
+
+       if (md->nid == NUMA_VAMAPS_NID_NONE)
+               md->nid = target;
+       if (md->nid == target)
+               return 0;
+       /* did not match */
+       md->nextaddr = addr;
+       return 1;
+}
+
 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
                unsigned long end, struct mm_walk *walk)
 {
@@ -1661,6 +1681,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long 
addr,
        spinlock_t *ptl;
        pte_t *orig_pte;
        pte_t *pte;
+       int ret = 0;
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
        ptl = pmd_trans_huge_lock(pmd, vma);
@@ -1668,11 +1689,13 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long 
addr,
                struct page *page;
 
                page = can_gather_numa_stats_pmd(*pmd, vma, addr);
-               if (page)
+               if (md->isvamaps)
+                       ret = vamap_match_nid(md, addr, page);
+               if (page && !ret)
                        gather_stats(page, md, pmd_dirty(*pmd),
                                     HPAGE_PMD_SIZE/PAGE_SIZE);
                spin_unlock(ptl);
-               return 0;
+               return ret;
        }
 
        if (pmd_trans_unstable(pmd))
@@ -1681,6 +1704,10 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long 
addr,
        orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
        do {
                struct page *page = can_gather_numa_stats(*pte, vma, addr);
+               if (md->isvamaps && vamap_match_nid(md, addr, page)) {
+                       ret = 1;
+                       break;
+               }
                if (!page)
                        continue;
                gather_stats(page, md, pte_dirty(*pte), 1);
@@ -1688,7 +1715,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long 
addr,
        } while (pte++, addr += PAGE_SIZE, addr != end);
        pte_unmap_unlock(orig_pte, ptl);
        cond_resched();
-       return 0;
+       return ret;
 }
 #ifdef CONFIG_HUGETLB_PAGE
 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
@@ -1697,15 +1724,18 @@ static int gather_hugetlb_stats(pte_t *pte, unsigned 
long hmask,
        pte_t huge_pte = huge_ptep_get(pte);
        struct numa_maps *md;
        struct page *page;
+       int ret = 0;
+       md = walk->private;
 
        if (!pte_present(huge_pte))
-               return 0;
+               return (md->isvamaps ? vamap_match_nid(md, addr, NULL) : 0);
 
        page = pte_page(huge_pte);
-       if (!page)
-               return 0;
+       if (md->isvamaps)
+               ret = vamap_match_nid(md, addr, page);
+       if (!page || ret)
+               return ret;
 
-       md = walk->private;
        gather_stats(page, md, pte_dirty(huge_pte), 1);
        return 0;
 }
-- 
2.7.4