The patch titled
Subject: delayacct: support swapin delay accounting for swapping without blkio
has been added to the -mm tree. Its filename is
delayacct-support-swapin-delay-accounting-for-swapping-without-blkio.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/delayacct-support-swapin-delay-accounting-for-swapping-without-blkio.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/delayacct-support-swapin-delay-accounting-for-swapping-without-blkio.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Yang Yang <yang.yang29@xxxxxxxxxx>
Subject: delayacct: support swapin delay accounting for swapping without blkio
Currently delayacct accounts swapin delay only for swapping that cause
blkio. If we use zram for swapping, tools/accounting/getdelays can't get
any SWAP delay.
It's useful to get zram swapin delay information, for example to adjust
compress algorithm or /proc/sys/vm/swappiness.
Reference to PSI, it accounts any kind of swapping by doing its work in
swap_readpage(), no matter whether swapping causes blkio. Let delayacct
do the similar work.
Link: https://lkml.kernel.org/r/20211112083813.8559-1-yang.yang29@xxxxxxxxxx
Signed-off-by: Yang Yang <yang.yang29@xxxxxxxxxx>
Reported-by: Zeal Robot <zealci@xxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/delayacct.h | 44 ++++++++++++++++++------------------
kernel/delayacct.c | 34 +++++++++++++++------------
mm/memory.c | 4 ---
mm/page_io.c | 3 ++
4 files changed, 44 insertions(+), 41 deletions(-)
--- a/include/linux/delayacct.h~delayacct-support-swapin-delay-accounting-for-swapping-without-blkio
+++ a/include/linux/delayacct.h
@@ -9,14 +9,6 @@
#include <uapi/linux/taskstats.h>
-/*
- * Per-task flags relevant to delay accounting
- * maintained privately to avoid exhausting similar flags in sched.h:PF_*
- * Used to set current->delays->flags
- */
-#define DELAYACCT_PF_SWAPIN 0x00000001 /* I am doing a swapin */
-#define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */
-
#ifdef CONFIG_TASK_DELAY_ACCT
struct task_delay_info {
raw_spinlock_t lock;
@@ -37,13 +29,13 @@ struct task_delay_info {
* associated with the operation is added to XXX_delay.
* XXX_delay contains the accumulated delay time in nanoseconds.
*/
- u64 blkio_start; /* Shared by blkio, swapin */
+ u64 blkio_start;
u64 blkio_delay; /* wait for sync block io completion */
- u64 swapin_delay; /* wait for swapin block io completion */
+ u64 swapin_start;
+ u64 swapin_delay; /* wait for swapin */
u32 blkio_count; /* total count of the number of sync block */
/* io operations performed */
- u32 swapin_count; /* total count of the number of swapin block */
- /* io operations performed */
+ u32 swapin_count; /* total count of swapin */
u64 freepages_start;
u64 freepages_delay; /* wait for memory reclaim */
@@ -79,14 +71,8 @@ extern void __delayacct_freepages_start(
extern void __delayacct_freepages_end(void);
extern void __delayacct_thrashing_start(void);
extern void __delayacct_thrashing_end(void);
-
-static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
-{
- if (p->delays)
- return (p->delays->flags & DELAYACCT_PF_BLKIO);
- else
- return 0;
-}
+extern void __delayacct_swapin_start(void);
+extern void __delayacct_swapin_end(void);
static inline void delayacct_set_flag(struct task_struct *p, int flag)
{
@@ -123,7 +109,6 @@ static inline void delayacct_blkio_start
if (!static_branch_unlikely(&delayacct_key))
return;
- delayacct_set_flag(current, DELAYACCT_PF_BLKIO);
if (current->delays)
__delayacct_blkio_start();
}
@@ -135,7 +120,6 @@ static inline void delayacct_blkio_end(s
if (p->delays)
__delayacct_blkio_end(p);
- delayacct_clear_flag(p, DELAYACCT_PF_BLKIO);
}
static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
@@ -169,6 +153,18 @@ static inline void delayacct_thrashing_e
__delayacct_thrashing_end();
}
+static inline void delayacct_swapin_start(void)
+{
+ if (current->delays)
+ __delayacct_swapin_start();
+}
+
+static inline void delayacct_swapin_end(void)
+{
+ if (current->delays)
+ __delayacct_swapin_end();
+}
+
#else
static inline void delayacct_set_flag(struct task_struct *p, int flag)
{}
@@ -199,6 +195,10 @@ static inline void delayacct_thrashing_s
{}
static inline void delayacct_thrashing_end(void)
{}
+static inline void delayacct_swapin_start(void)
+{}
+static inline void delayacct_swapin_end(void)
+{}
#endif /* CONFIG_TASK_DELAY_ACCT */
--- a/kernel/delayacct.c~delayacct-support-swapin-delay-accounting-for-swapping-without-blkio
+++ a/kernel/delayacct.c
@@ -100,19 +100,10 @@ void __delayacct_blkio_start(void)
*/
void __delayacct_blkio_end(struct task_struct *p)
{
- struct task_delay_info *delays = p->delays;
- u64 *total;
- u32 *count;
-
- if (p->delays->flags & DELAYACCT_PF_SWAPIN) {
- total = &delays->swapin_delay;
- count = &delays->swapin_count;
- } else {
- total = &delays->blkio_delay;
- count = &delays->blkio_count;
- }
-
- delayacct_end(&delays->lock, &delays->blkio_start, total, count);
+ delayacct_end(&p->delays->lock,
+ &p->delays->blkio_start,
+ &p->delays->blkio_delay,
+ &p->delays->blkio_count);
}
int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
@@ -179,8 +170,7 @@ __u64 __delayacct_blkio_ticks(struct tas
unsigned long flags;
raw_spin_lock_irqsave(&tsk->delays->lock, flags);
- ret = nsec_to_clock_t(tsk->delays->blkio_delay +
- tsk->delays->swapin_delay);
+ ret = nsec_to_clock_t(tsk->delays->blkio_delay);
raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return ret;
}
@@ -210,3 +200,17 @@ void __delayacct_thrashing_end(void)
¤t->delays->thrashing_delay,
¤t->delays->thrashing_count);
}
+
+void __delayacct_swapin_start(void)
+{
+ current->delays->swapin_start = local_clock();
+}
+
+void __delayacct_swapin_end(void)
+{
+ delayacct_end(¤t->delays->lock,
+ ¤t->delays->swapin_start,
+ ¤t->delays->swapin_delay,
+ ¤t->delays->swapin_count);
+}
+
--- a/mm/memory.c~delayacct-support-swapin-delay-accounting-for-swapping-without-blkio
+++ a/mm/memory.c
@@ -3507,7 +3507,6 @@ vm_fault_t do_swap_page(struct vm_fault
if (unlikely(!si))
goto out;
- delayacct_set_flag(current, DELAYACCT_PF_SWAPIN);
page = lookup_swap_cache(entry, vma, vmf->address);
swapcache = page;
@@ -3555,7 +3554,6 @@ vm_fault_t do_swap_page(struct vm_fault
vmf->address, &vmf->ptl);
if (likely(pte_same(*vmf->pte, vmf->orig_pte)))
ret = VM_FAULT_OOM;
- delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN);
goto unlock;
}
@@ -3569,13 +3567,11 @@ vm_fault_t do_swap_page(struct vm_fault
* owner processes (which may be unknown at hwpoison time)
*/
ret = VM_FAULT_HWPOISON;
- delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN);
goto out_release;
}
locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags);
- delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN);
if (!locked) {
ret |= VM_FAULT_RETRY;
goto out_release;
--- a/mm/page_io.c~delayacct-support-swapin-delay-accounting-for-swapping-without-blkio
+++ a/mm/page_io.c
@@ -25,6 +25,7 @@
#include <linux/psi.h>
#include <linux/uio.h>
#include <linux/sched/task.h>
+#include <linux/delayacct.h>
void end_swap_bio_write(struct bio *bio)
{
@@ -370,6 +371,7 @@ int swap_readpage(struct page *page, boo
* significant part of overall IO time.
*/
psi_memstall_enter(&pflags);
+ delayacct_swapin_start();
if (frontswap_load(page) == 0) {
SetPageUptodate(page);
@@ -432,6 +434,7 @@ int swap_readpage(struct page *page, boo
out:
psi_memstall_leave(&pflags);
+ delayacct_swapin_end();
return ret;
}
_
Patches currently in -mm which might be from yang.yang29@xxxxxxxxxx are
delayacct-support-swapin-delay-accounting-for-swapping-without-blkio.patch
