From aa1cf99b87e934e761b46ce2b925335a398980da Mon Sep 17 00:00:00 2001 From: Yang Yang Date: Mon, 15 Aug 2022 07:11:35 +0000 Subject: [PATCH] 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 aae466b0052e ("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: Yang Yang Signed-off-by: CGEL ZTE Reviewed-by: Ran Xiaokai Reviewed-by: wangyong Acked-by: Joonsoo Kim Signed-off-by: Andrew Morton --- 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(-) 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 e7b2f8a5c711..d9a2466664f7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -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. */ 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) ¤t->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(¤t->delays->lock, ¤t->delays->thrashing_start, ¤t->delays->thrashing_delay, diff --git a/mm/filemap.c b/mm/filemap.c index 5570d083ec0f..68bd70fe71d5 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 @@ repeat: 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); } }