So user could check those interface for more detailed
information about how much DAX mappings are currently
created.
Here we use vma_is_dax method to find specific page
struture with DAX {huge, normal}page mappings,
vm_normal_page routine works as before without any
impact on the existing logical where _vm_normal_page
are called.
With this patch, user could check Device DAX usage at Ptes@ readings,
fox example, statistics from a Device DAX algined by 2MB:
7f6c17800000-7f6c17e00000 rw-s 00000000 00:06 20559 /dev/dax12.0
Size: 6144 kB
.
.
.
Ptes@2MB: 6144 kB
Signed-off-by: Fan Du <fan.du@xxxxxxxxx>
---
v3:
* Elaborate more about the usage suggested by Michal Hocko
v2:
* Using pte_devmap to check valid pfn page structure,
Pointed out by Dan. thx!
---
fs/proc/task_mmu.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 30dbf37..5c4535c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -531,7 +531,10 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
struct page *page = NULL;
if (pte_present(*pte)) {
- page = vm_normal_page(vma, addr, *pte);
+ if (!vma_is_dax(vma))
+ page = vm_normal_page(vma, addr, *pte);
+ else if (pte_devmap(*pte))
+ page = pte_page(*pte);
mss->rss_pte += PAGE_SIZE;
} else if (is_swap_pte(*pte)) {
swp_entry_t swpent = pte_to_swp_entry(*pte);
@@ -583,7 +586,11 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
struct page *page;
/* FOLL_DUMP will return -EFAULT on huge zero page */
- page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
+ if (!vma_is_dax(vma))
+ page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
+ else if (pmd_devmap(*pmd))
+ page = pmd_page(*pmd);
+
if (IS_ERR_OR_NULL(page))
return;
if (PageAnon(page))
@@ -1770,13 +1777,15 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
spinlock_t *ptl;
pte_t *orig_pte;
pte_t *pte;
+ struct page *page;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
- struct page *page;
-
- page = can_gather_numa_stats_pmd(*pmd, vma, addr);
+ if (!vma_is_dax(vma))
+ page = can_gather_numa_stats_pmd(*pmd, vma, addr);
+ else if (pmd_devmap(*pmd))
+ page = pmd_page(*pmd);
if (page)
gather_stats(page, md, pmd_dirty(*pmd),
HPAGE_PMD_SIZE/PAGE_SIZE);
@@ -1789,7 +1798,10 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
#endif
orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
do {
- struct page *page = can_gather_numa_stats(*pte, vma, addr);
+ if (!vma_is_dax(vma))
+ page = can_gather_numa_stats(*pte, vma, addr);
+ else if (pte_devmap(*pte))
+ page = pte_page(*pte);
if (!page)
continue;
gather_stats(page, md, pte_dirty(*pte), 1);
--
1.8.3.1
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