2022-08-05 03:43:21

by CGEL

Subject: [PATCH] filemap: Make the accounting of thrashing more consistent

From: Yang Yang <[email protected]>

Once upon a time, we only support accounting thrashing of page cache.
Then Joonsoo introduced workingset detection for anonymous pages and
we gained the ability to account thrashing of them[1].

So let delayacct account both the thrashing of page cache and anonymous
pages, this could make the codes more consistent and simpler.

[1] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")

Signed-off-by: Yang Yang <[email protected]>
Signed-off-by: CGEL ZTE <[email protected]>
---
Documentation/accounting/delay-accounting.rst | 2 +-
mm/filemap.c | 18 ++++--------------
2 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst
index 241d1a87f2cd..7103b62ba6d7 100644
--- a/Documentation/accounting/delay-accounting.rst
+++ b/Documentation/accounting/delay-accounting.rst
@@ -13,7 +13,7 @@ a) waiting for a CPU (while being runnable)
b) completion of synchronous block I/O initiated by the task
c) swapping in pages
d) memory reclaim
-e) thrashing page cache
+e) thrashing
f) direct compact
g) write-protect copy

diff --git a/mm/filemap.c b/mm/filemap.c
index 15800334147b..cfe15e89b3c2 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1221,15 +1221,11 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
struct wait_page_queue wait_page;
wait_queue_entry_t *wait = &wait_page.wait;
bool thrashing = false;
- bool delayacct = false;
unsigned long pflags;

if (bit_nr == PG_locked &&
!folio_test_uptodate(folio) && folio_test_workingset(folio)) {
- if (!folio_test_swapbacked(folio)) {
- delayacct_thrashing_start();
- delayacct = true;
- }
+ delayacct_thrashing_start();
psi_memstall_enter(&pflags);
thrashing = true;
}
@@ -1329,8 +1325,7 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
finish_wait(q, wait);

if (thrashing) {
- if (delayacct)
- delayacct_thrashing_end();
+ delayacct_thrashing_end();
psi_memstall_leave(&pflags);
}

@@ -1378,17 +1373,13 @@ void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
struct wait_page_queue wait_page;
wait_queue_entry_t *wait = &wait_page.wait;
bool thrashing = false;
- bool delayacct = false;
unsigned long pflags;
wait_queue_head_t *q;
struct folio *folio = page_folio(pfn_swap_entry_to_page(entry));

q = folio_waitqueue(folio);
if (!folio_test_uptodate(folio) && folio_test_workingset(folio)) {
- if (!folio_test_swapbacked(folio)) {
- delayacct_thrashing_start();
- delayacct = true;
- }
+ delayacct_thrashing_start();
psi_memstall_enter(&pflags);
thrashing = true;
}
@@ -1435,8 +1426,7 @@ void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
finish_wait(q, wait);

if (thrashing) {
- if (delayacct)
- delayacct_thrashing_end();
+ delayacct_thrashing_end();
psi_memstall_leave(&pflags);
}
}
--
2.25.1

2022-09-14 14:44:04

by Joonsoo Kim

Subject: Re: [PATCH] filemap: Make the accounting of thrashing more consistent

2022년 8월 5일 (금) 오후 12:39, <[email protected]>님이 작성:
>
> From: Yang Yang <[email protected]>
>
> Once upon a time, we only support accounting thrashing of page cache.
> Then Joonsoo introduced workingset detection for anonymous pages and
> we gained the ability to account thrashing of them[1].
>
> So let delayacct account both the thrashing of page cache and anonymous
> pages, this could make the codes more consistent and simpler.
>
> [1] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")
>
> Signed-off-by: Yang Yang <[email protected]>
> Signed-off-by: CGEL ZTE <[email protected]>

Acked-by: Joonsoo Kim <[email protected]>