[v2,5/7] mm: task_mmu: use a folio in smaps_account()
Commit Message
Replace seven implicit calls to compound_head() with one page_folio().
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
fs/proc/task_mmu.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
Comments
On Fri, Nov 10, 2023 at 11:33:22AM +0800, Kefeng Wang wrote:
> Replace seven implicit calls to compound_head() with one page_folio().
You're so focused on trying to accomplish your goal (killing off the
page_idle and page_young functions) that you're doing a poor job thinkig
about the conversions you're doing along the way.
> +++ b/fs/proc/task_mmu.c
> @@ -445,23 +445,25 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
> {
> int i, nr = compound ? compound_nr(page) : 1;
> unsigned long size = nr * PAGE_SIZE;
> + struct folio *folio = page_folio(page);
Stop right here. The use of compound_nr() should give you pause.
After looking at how smaps_account() is used, it seems to me that the
two callers should each pass in PAGE_SIZE or PMD_SIZE instead of doing
this calculation.
More generally, step back from this series. Do a good job of
transforming fs/proc/task_mmu.c to use folios. Once you've done
that, you can approach the young/idle work again.
On 2023/11/11 2:29, Matthew Wilcox wrote:
> On Fri, Nov 10, 2023 at 11:33:22AM +0800, Kefeng Wang wrote:
>> Replace seven implicit calls to compound_head() with one page_folio().
>
> You're so focused on trying to accomplish your goal (killing off the
> page_idle and page_young functions) that you're doing a poor job thinkig
> about the conversions you're doing along the way.
>
>> +++ b/fs/proc/task_mmu.c
>> @@ -445,23 +445,25 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
>> {
>> int i, nr = compound ? compound_nr(page) : 1;
>> unsigned long size = nr * PAGE_SIZE;
>> + struct folio *folio = page_folio(page);
>
> Stop right here. The use of compound_nr() should give you pause.
>
> After looking at how smaps_account() is used, it seems to me that the
> two callers should each pass in PAGE_SIZE or PMD_SIZE instead of doing
> this calculation.
Yes，this will save extra calculation
>
> More generally, step back from this series. Do a good job of
> transforming fs/proc/task_mmu.c to use folios. Once you've done
> that, you can approach the young/idle work again.
>
Thanks for you advise，will try this firstly.
>
@@ -445,23 +445,25 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
{
int i, nr = compound ? compound_nr(page) : 1;
unsigned long size = nr * PAGE_SIZE;
+ struct folio *folio = page_folio(page);
/*
* First accumulate quantities that depend only on |size| and the type
* of the compound page.
*/
- if (PageAnon(page)) {
+ if (folio_test_anon(folio)) {
mss->anonymous += size;
- if (!PageSwapBacked(page) && !dirty && !PageDirty(page))
+ if (!folio_test_swapbacked(folio) && !dirty &&
+ !folio_test_dirty(folio))
mss->lazyfree += size;
}
- if (PageKsm(page))
+ if (folio_test_ksm(folio))
mss->ksm += size;
mss->resident += size;
/* Accumulate the size in pages that have been accessed. */
- if (young || page_is_young(page) || PageReferenced(page))
+ if (young || folio_test_young(folio) || folio_test_referenced(folio))
mss->referenced += size;
/*
@@ -479,7 +481,7 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
* especially for migration entries. Treat regular migration entries
* as mapcount == 1.
*/
- if ((page_count(page) == 1) || migration) {
+ if ((folio_ref_count(folio) == 1) || migration) {
smaps_page_accumulate(mss, page, size, size << PSS_SHIFT, dirty,
locked, true);
return;