Commit aa1cf99b authored by Yang Yang's avatar Yang Yang Committed by Andrew Morton
Browse files

delayacct: support re-entrance detection of thrashing accounting 

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 aae466b0 ("mm/swap: implement workingset detection for anonymous LRU")

Link: https://lkml.kernel.org/r/20220815071134.74551-1-yang.yang29@zte.com.cn


Signed-off-by: default avatarYang Yang <yang.yang29@zte.com.cn>
Signed-off-by: default avatarCGEL ZTE <cgel.zte@gmail.com>
Reviewed-by: default avatarRan Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: default avatarwangyong <wang.yong12@zte.com.cn>
Acked-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7047b5a4

include/linux/delayacct.h

+8 −8
Original line number Diff line number Diff line
@@ -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)

{}

include/linux/sched.h

+4 −0
Original line number Diff line number Diff line
@@ -944,6 +944,10 @@ 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. */

kernel/delayacct.c

+11 −2
Original line number Diff line number Diff line
@@ -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,

mm/filemap.c

+6 −4
Original line number Diff line number Diff line
@@ -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);

	}

}