Re: [PATCH RFC 6/6] mm: madvise: don't split mTHP for MADV_PAGEOUT

Barry Song
2024-02-28T03:49:32Z

>> I'm going to rework this patch and integrate it into my series if that's ok with
>> you?
>
> This is perfect. Please integrate it into your swap-out series which is the
> perfect place for this MADV_PAGEOUT.

BTW, Ryan, while you integrate this into your swap-put series, can you also
add the below one which is addressing one comment of Chris,

From: Barry Song <v-songbaohua@oppo.com>
Date: Tue, 27 Feb 2024 22:03:59 +1300
Subject: [PATCH] mm: madvise: extract common function
folio_deactivate_or_add_to_reclaim_list

For madvise_cold_or_pageout_pte_range, both pmd-mapped and pte-mapped
normal folios are duplicating the same code right now, and we might
have more such as pte-mapped large folios to use it. It is better
to extract a common function.

Cc: Chris Li <chrisl@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
---
mm/madvise.c | 52 ++++++++++++++++++++--------------------------------
1 file changed, 20 insertions(+), 32 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 44a498c94158..1812457144ea 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -321,6 +321,24 @@ static inline bool can_do_file_pageout(struct vm_area_struct *vma)
file_permission(vma->vm_file, MAY_WRITE) == 0;
}

+static inline void folio_deactivate_or_add_to_reclaim_list(struct folio *folio, bool pageout,
+ struct list_head *folio_list)
+{
+ folio_clear_referenced(folio);
+ folio_test_clear_young(folio);
+
+ if (folio_test_active(folio))
+ folio_set_workingset(folio);
+ if (!pageout)
+ return folio_deactivate(folio);
+ if (folio_isolate_lru(folio)) {
+ if (folio_test_unevictable(folio))
+ folio_putback_lru(folio);
+ else
+ list_add(&folio->lru, folio_list);
+ }
+}
+
static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
@@ -394,19 +412,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
}

- folio_clear_referenced(folio);
- folio_test_clear_young(folio);
- if (folio_test_active(folio))
- folio_set_workingset(folio);
- if (pageout) {
- if (folio_isolate_lru(folio)) {
- if (folio_test_unevictable(folio))
- folio_putback_lru(folio);
- else
- list_add(&folio->lru, &folio_list);
- }
- } else
- folio_deactivate(folio);
+ folio_deactivate_or_add_to_reclaim_list(folio, pageout, &folio_list);
huge_unlock:
spin_unlock(ptl);
if (pageout)
@@ -498,25 +504,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
tlb_remove_tlb_entry(tlb, pte, addr);
}

- /*
- * We are deactivating a folio for accelerating reclaiming.
- * VM couldn't reclaim the folio unless we clear PG_young.
- * As a side effect, it makes confuse idle-page tracking
- * because they will miss recent referenced history.
- */
- folio_clear_referenced(folio);
- folio_test_clear_young(folio);
- if (folio_test_active(folio))
- folio_set_workingset(folio);
- if (pageout) {
- if (folio_isolate_lru(folio)) {
- if (folio_test_unevictable(folio))
- folio_putback_lru(folio);
- else
- list_add(&folio->lru, &folio_list);
- }
- } else
- folio_deactivate(folio);
+ folio_deactivate_or_add_to_reclaim_list(folio, pageout, &folio_list);
}

if (start_pte) {
--
2.34.1

Thanks
Barry