diff mbox series

[v2,1/2] delayacct: support re-entrance detection of thrashing accounting

Message ID 20220815071134.74551-1-yang.yang29@zte.com.cn (mailing list archive)
State New
Headers show
Series [v2,1/2] delayacct: support re-entrance detection of thrashing accounting | expand

Commit Message

CGEL Aug. 15, 2022, 7:11 a.m. UTC 
From: Yang Yang <yang.yang29@zte.com.cn>

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].

For page cache thrashing accounting, there is no suitable place to do
it in fs level likes swap_readpage(). So we have to do it in
folio_wait_bit_common().

Then for anonymous pages thrashing accounting, we have to do it in
both swap_readpage() and folio_wait_bit_common(). This likes PSI,
so we should let thrashing accounting supports re-entrance detection.

This patch is to prepare complete thrashing accounting, and is based
on patch "filemap: make the accounting of thrashing more consistent".

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

Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: CGEL ZTE <cgel.zte@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: wangyong <wang.yong12@zte.com.cn>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
Change for v2:
 - use bool *in_thrashing instead of unsigned long *flags
---
 include/linux/delayacct.h | 16 ++++++++--------
 include/linux/sched.h     |  4 ++++
 kernel/delayacct.c        | 13 +++++++++++--
 mm/filemap.c              | 10 ++++++----
 4 files changed, 29 insertions(+), 14 deletions(-)

Comments

Joonsoo Kim Sept. 14, 2022, 2:37 p.m. UTC | #1 
2022년 8월 15일 (월) 오후 4:14, <cgel.zte@gmail.com>님이 작성:
>
> From: Yang Yang <yang.yang29@zte.com.cn>
>
> 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].
>
> For page cache thrashing accounting, there is no suitable place to do
> it in fs level likes swap_readpage(). So we have to do it in
> folio_wait_bit_common().
>
> Then for anonymous pages thrashing accounting, we have to do it in
> both swap_readpage() and folio_wait_bit_common(). This likes PSI,
> so we should let thrashing accounting supports re-entrance detection.
>
> This patch is to prepare complete thrashing accounting, and is based
> on patch "filemap: make the accounting of thrashing more consistent".
>
> [1] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")
>
> Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
> Signed-off-by: CGEL ZTE <cgel.zte@gmail.com>
> Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
> Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> Reviewed-by: wangyong <wang.yong12@zte.com.cn>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
diff mbox series

Patch

diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h
index 58aea2d7385c..0da97dba9ef8 100644
--- a/include/linux/delayacct.h
+++ b/include/linux/delayacct.h
@@ -73,8 +73,8 @@  extern int delayacct_add_tsk(struct taskstats *, struct task_struct *);
 extern __u64 __delayacct_blkio_ticks(struct task_struct *);
 extern void __delayacct_freepages_start(void);
 extern void __delayacct_freepages_end(void);
-extern void __delayacct_thrashing_start(void);
-extern void __delayacct_thrashing_end(void);
+extern void __delayacct_thrashing_start(bool *in_thrashing);
+extern void __delayacct_thrashing_end(bool *in_thrashing);
 extern void __delayacct_swapin_start(void);
 extern void __delayacct_swapin_end(void);
 extern void __delayacct_compact_start(void);
@@ -143,22 +143,22 @@  static inline void delayacct_freepages_end(void)
 		__delayacct_freepages_end();
 }
 
-static inline void delayacct_thrashing_start(void)
+static inline void delayacct_thrashing_start(bool *in_thrashing)
 {
 	if (!static_branch_unlikely(&delayacct_key))
 		return;
 
 	if (current->delays)
-		__delayacct_thrashing_start();
+		__delayacct_thrashing_start(in_thrashing);
 }
 
-static inline void delayacct_thrashing_end(void)
+static inline void delayacct_thrashing_end(bool *in_thrashing)
 {
 	if (!static_branch_unlikely(&delayacct_key))
 		return;
 
 	if (current->delays)
-		__delayacct_thrashing_end();
+		__delayacct_thrashing_end(in_thrashing);
 }
 
 static inline void delayacct_swapin_start(void)
@@ -237,9 +237,9 @@  static inline void delayacct_freepages_start(void)
 {}
 static inline void delayacct_freepages_end(void)
 {}
-static inline void delayacct_thrashing_start(void)
+static inline void delayacct_thrashing_start(bool *in_thrashing)
 {}
-static inline void delayacct_thrashing_end(void)
+static inline void delayacct_thrashing_end(bool *in_thrashing)
 {}
 static inline void delayacct_swapin_start(void)
 {}
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d6b0866c71ed..5fb942e29583 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -943,6 +943,10 @@  struct task_struct {
 #ifdef	CONFIG_CPU_SUP_INTEL
 	unsigned			reported_split_lock:1;
 #endif
+#ifdef CONFIG_TASK_DELAY_ACCT
+	/* delay due to memory thrashing */
+	unsigned                        in_thrashing:1;
+#endif
 
 	unsigned long			atomic_flags; /* Flags requiring atomic access. */
 
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 164ed9ef77a3..e39cb696cfbd 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -214,13 +214,22 @@  void __delayacct_freepages_end(void)
 		      &current->delays->freepages_count);
 }
 
-void __delayacct_thrashing_start(void)
+void __delayacct_thrashing_start(bool *in_thrashing)
 {
+	*in_thrashing = !!current->in_thrashing;
+	if (*in_thrashing)
+		return;
+
+	current->in_thrashing = 1;
 	current->delays->thrashing_start = local_clock();
 }
 
-void __delayacct_thrashing_end(void)
+void __delayacct_thrashing_end(bool *in_thrashing)
 {
+	if (*in_thrashing)
+		return;
+
+	current->in_thrashing = 0;
 	delayacct_end(&current->delays->lock,
 		      &current->delays->thrashing_start,
 		      &current->delays->thrashing_delay,
diff --git a/mm/filemap.c b/mm/filemap.c
index cfe15e89b3c2..bc37a93bb29a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1222,10 +1222,11 @@  static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
 	wait_queue_entry_t *wait = &wait_page.wait;
 	bool thrashing = false;
 	unsigned long pflags;
+	bool in_thrashing;
 
 	if (bit_nr == PG_locked &&
 	    !folio_test_uptodate(folio) && folio_test_workingset(folio)) {
-		delayacct_thrashing_start();
+		delayacct_thrashing_start(&in_thrashing);
 		psi_memstall_enter(&pflags);
 		thrashing = true;
 	}
@@ -1325,7 +1326,7 @@  static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
 	finish_wait(q, wait);
 
 	if (thrashing) {
-		delayacct_thrashing_end();
+		delayacct_thrashing_end(&in_thrashing);
 		psi_memstall_leave(&pflags);
 	}
 
@@ -1374,12 +1375,13 @@  void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
 	wait_queue_entry_t *wait = &wait_page.wait;
 	bool thrashing = false;
 	unsigned long pflags;
+	bool in_thrashing;
 	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)) {
-		delayacct_thrashing_start();
+		delayacct_thrashing_start(&in_thrashing);
 		psi_memstall_enter(&pflags);
 		thrashing = true;
 	}
@@ -1426,7 +1428,7 @@  void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
 	finish_wait(q, wait);
 
 	if (thrashing) {
-		delayacct_thrashing_end();
+		delayacct_thrashing_end(&in_thrashing);
 		psi_memstall_leave(&pflags);
 	}
 }