2024-04-22 07:34:02

by Baolin Wang

Subject: [PATCH v2] mm: huge_memory: add the missing folio_test_pmd_mappable() for THP split statistics

Now the mTHP can also be split or added into the deferred list, so add
folio_test_pmd_mappable() validation for PMD mapped THP, to avoid confusion
with PMD mapped THP related statistics.

Signed-off-by: Baolin Wang <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
---
Changes from v1:
- Add acked tag from David.
- Check the THP earlier in case the folio is split per Lance.
---
mm/huge_memory.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 716d29c21b6e..a9789ca823bc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2994,6 +2994,7 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
XA_STATE_ORDER(xas, &folio->mapping->i_pages, folio->index, new_order);
struct anon_vma *anon_vma = NULL;
struct address_space *mapping = NULL;
+ bool is_thp = folio_test_pmd_mappable(folio);
int extra_pins, ret;
pgoff_t end;
bool is_hzp;
@@ -3172,7 +3173,8 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
i_mmap_unlock_read(mapping);
out:
xas_destroy(&xas);
- count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
+ if (is_thp)
+ count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
return ret;
}

@@ -3234,7 +3236,8 @@ void deferred_split_folio(struct folio *folio)

spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
if (list_empty(&folio->_deferred_list)) {
- count_vm_event(THP_DEFERRED_SPLIT_PAGE);
+ if (folio_test_pmd_mappable(folio))
+ count_vm_event(THP_DEFERRED_SPLIT_PAGE);
list_add_tail(&folio->_deferred_list, &ds_queue->split_queue);
ds_queue->split_queue_len++;
#ifdef CONFIG_MEMCG
--
2.39.3

2024-04-22 07:58:32

by Lance Yang

Subject: Re: [PATCH v2] mm: huge_memory: add the missing folio_test_pmd_mappable() for THP split statistics

On Mon, Apr 22, 2024 at 3:33 PM Baolin Wang
<[email protected]> wrote:
>
> Now the mTHP can also be split or added into the deferred list, so add
> folio_test_pmd_mappable() validation for PMD mapped THP, to avoid confusion
> with PMD mapped THP related statistics.
>
> Signed-off-by: Baolin Wang <[email protected]>
> Acked-by: David Hildenbrand <[email protected]>

LGTM!

Reviewed-by: Lance Yang <[email protected]>

Thanks,
Lance

> ---
> Changes from v1:
> - Add acked tag from David.
> - Check the THP earlier in case the folio is split per Lance.
> ---
> mm/huge_memory.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 716d29c21b6e..a9789ca823bc 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -2994,6 +2994,7 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
> XA_STATE_ORDER(xas, &folio->mapping->i_pages, folio->index, new_order);
> struct anon_vma *anon_vma = NULL;
> struct address_space *mapping = NULL;
> + bool is_thp = folio_test_pmd_mappable(folio);
> int extra_pins, ret;
> pgoff_t end;
> bool is_hzp;
> @@ -3172,7 +3173,8 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
> i_mmap_unlock_read(mapping);
> out:
> xas_destroy(&xas);
> - count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
> + if (is_thp)
> + count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
> return ret;
> }
>
> @@ -3234,7 +3236,8 @@ void deferred_split_folio(struct folio *folio)
>
> spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
> if (list_empty(&folio->_deferred_list)) {
> - count_vm_event(THP_DEFERRED_SPLIT_PAGE);
> + if (folio_test_pmd_mappable(folio))
> + count_vm_event(THP_DEFERRED_SPLIT_PAGE);
> list_add_tail(&folio->_deferred_list, &ds_queue->split_queue);
> ds_queue->split_queue_len++;
> #ifdef CONFIG_MEMCG
> --
> 2.39.3
>