The patch titled
Subject: delayacct: track delays from thrashing cache pages
has been removed from the -mm tree. Its filename was
delayacct-track-delays-from-thrashing-cache-pages.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: delayacct: track delays from thrashing cache pages
Delay accounting already measures the time a task spends in direct reclaim
and waiting for swapin, but in low memory situations tasks spend can spend
a significant amount of their time waiting on thrashing page cache. This
isn't tracked right now.
To know the full impact of memory contention on an individual task,
measure the delay when waiting for a recently evicted active cache page to
read back into memory.
Also update tools/accounting/getdelays.c:
[hannes@computer accounting]$ sudo ./getdelays -d -p 1
print delayacct stats ON
PID 1
CPU count real total virtual total delay total delay average
50318 745000000 847346785 400533713 0.008ms
IO count delay total delay average
435 122601218 0ms
SWAP count delay total delay average
0 0 0ms
RECLAIM count delay total delay average
0 0 0ms
THRASHING count delay total delay average
19 12621439 0ms
Link: http://lkml.kernel.org/r/20180712172942.10094-4-hannes@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Tested-by: Daniel Drake <drake@xxxxxxxxxxxx>
Cc: Christopher Lameter <cl@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Johannes Weiner <jweiner@xxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vinayak Menon <vinmenon@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/delayacct.h | 23 +++++++++++++++++++++++
include/uapi/linux/taskstats.h | 6 +++++-
kernel/delayacct.c | 15 +++++++++++++++
mm/filemap.c | 11 +++++++++++
tools/accounting/getdelays.c | 8 +++++++-
5 files changed, 61 insertions(+), 2 deletions(-)
diff -puN include/linux/delayacct.h~delayacct-track-delays-from-thrashing-cache-pages include/linux/delayacct.h
--- a/include/linux/delayacct.h~delayacct-track-delays-from-thrashing-cache-pages
+++ a/include/linux/delayacct.h
@@ -57,7 +57,12 @@ struct task_delay_info {
u64 freepages_start;
u64 freepages_delay; /* wait for memory reclaim */
+
+ u64 thrashing_start;
+ u64 thrashing_delay; /* wait for thrashing page */
+
u32 freepages_count; /* total count of memory reclaim */
+ u32 thrashing_count; /* total count of thrash waits */
};
#endif
@@ -76,6 +81,8 @@ extern int __delayacct_add_tsk(struct ta
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);
static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
{
@@ -156,6 +163,18 @@ static inline void delayacct_freepages_e
__delayacct_freepages_end();
}
+static inline void delayacct_thrashing_start(void)
+{
+ if (current->delays)
+ __delayacct_thrashing_start();
+}
+
+static inline void delayacct_thrashing_end(void)
+{
+ if (current->delays)
+ __delayacct_thrashing_end();
+}
+
#else
static inline void delayacct_set_flag(int flag)
{}
@@ -182,6 +201,10 @@ static inline void delayacct_freepages_s
{}
static inline void delayacct_freepages_end(void)
{}
+static inline void delayacct_thrashing_start(void)
+{}
+static inline void delayacct_thrashing_end(void)
+{}
#endif /* CONFIG_TASK_DELAY_ACCT */
diff -puN include/uapi/linux/taskstats.h~delayacct-track-delays-from-thrashing-cache-pages include/uapi/linux/taskstats.h
--- a/include/uapi/linux/taskstats.h~delayacct-track-delays-from-thrashing-cache-pages
+++ a/include/uapi/linux/taskstats.h
@@ -34,7 +34,7 @@
*/
-#define TASKSTATS_VERSION 8
+#define TASKSTATS_VERSION 9
#define TS_COMM_LEN 32 /* should be >= TASK_COMM_LEN
* in linux/sched.h */
@@ -164,6 +164,10 @@ struct taskstats {
/* Delay waiting for memory reclaim */
__u64 freepages_count;
__u64 freepages_delay_total;
+
+ /* Delay waiting for thrashing page */
+ __u64 thrashing_count;
+ __u64 thrashing_delay_total;
};
diff -puN kernel/delayacct.c~delayacct-track-delays-from-thrashing-cache-pages kernel/delayacct.c
--- a/kernel/delayacct.c~delayacct-track-delays-from-thrashing-cache-pages
+++ a/kernel/delayacct.c
@@ -135,9 +135,12 @@ int __delayacct_add_tsk(struct taskstats
d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
+ tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
+ d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
d->blkio_count += tsk->delays->blkio_count;
d->swapin_count += tsk->delays->swapin_count;
d->freepages_count += tsk->delays->freepages_count;
+ d->thrashing_count += tsk->delays->thrashing_count;
raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return 0;
@@ -169,3 +172,15 @@ void __delayacct_freepages_end(void)
¤t->delays->freepages_count);
}
+void __delayacct_thrashing_start(void)
+{
+ current->delays->thrashing_start = ktime_get_ns();
+}
+
+void __delayacct_thrashing_end(void)
+{
+ delayacct_end(¤t->delays->lock,
+ ¤t->delays->thrashing_start,
+ ¤t->delays->thrashing_delay,
+ ¤t->delays->thrashing_count);
+}
diff -puN mm/filemap.c~delayacct-track-delays-from-thrashing-cache-pages mm/filemap.c
--- a/mm/filemap.c~delayacct-track-delays-from-thrashing-cache-pages
+++ a/mm/filemap.c
@@ -36,6 +36,7 @@
#include <linux/cleancache.h>
#include <linux/shmem_fs.h>
#include <linux/rmap.h>
+#include <linux/delayacct.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
@@ -1073,8 +1074,15 @@ static inline int wait_on_page_bit_commo
{
struct wait_page_queue wait_page;
wait_queue_entry_t *wait = &wait_page.wait;
+ bool thrashing = false;
int ret = 0;
+ if (bit_nr == PG_locked && !PageSwapBacked(page) &&
+ !PageUptodate(page) && PageWorkingset(page)) {
+ delayacct_thrashing_start();
+ thrashing = true;
+ }
+
init_wait(wait);
wait->flags = lock ? WQ_FLAG_EXCLUSIVE : 0;
wait->func = wake_page_function;
@@ -1113,6 +1121,9 @@ static inline int wait_on_page_bit_commo
finish_wait(q, wait);
+ if (thrashing)
+ delayacct_thrashing_end();
+
/*
* A signal could leave PageWaiters set. Clearing it here if
* !waitqueue_active would be possible (by open-coding finish_wait),
diff -puN tools/accounting/getdelays.c~delayacct-track-delays-from-thrashing-cache-pages tools/accounting/getdelays.c
--- a/tools/accounting/getdelays.c~delayacct-track-delays-from-thrashing-cache-pages
+++ a/tools/accounting/getdelays.c
@@ -203,6 +203,8 @@ static void print_delayacct(struct tasks
"SWAP %15s%15s%15s\n"
" %15llu%15llu%15llums\n"
"RECLAIM %12s%15s%15s\n"
+ " %15llu%15llu%15llums\n"
+ "THRASHING%12s%15s%15s\n"
" %15llu%15llu%15llums\n",
"count", "real total", "virtual total",
"delay total", "delay average",
@@ -222,7 +224,11 @@ static void print_delayacct(struct tasks
"count", "delay total", "delay average",
(unsigned long long)t->freepages_count,
(unsigned long long)t->freepages_delay_total,
- average_ms(t->freepages_delay_total, t->freepages_count));
+ average_ms(t->freepages_delay_total, t->freepages_count),
+ "count", "delay total", "delay average",
+ (unsigned long long)t->thrashing_count,
+ (unsigned long long)t->thrashing_delay_total,
+ average_ms(t->thrashing_delay_total, t->thrashing_count));
}
static void task_context_switch_counts(struct taskstats *t)
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
sched-loadavg-consolidate-load_int-load_frac-calc_load.patch
sched-loadavg-make-calc_load_n-public.patch
sched-schedh-make-rq-locking-and-clock-functions-available-in-statsh.patch
sched-introduce-this_rq_lock_irq.patch
psi-pressure-stall-information-for-cpu-memory-and-io.patch
psi-cgroup-support.patch
psi-aggregate-ongoing-stall-events-when-somebody-reads-pressure.patch
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