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873b477177
Sometimes, application responses become bad under heavy memory load.
Applications take a bit time to reclaim memory. The statistics, how long
memory reclaim takes, will be useful to measure memory usage.
This patch adds accounting memory reclaim to per-task-delay-accounting for
accounting the time of do_try_to_free_pages().
<i.e>
- When System is under low memory load,
memory reclaim may not occur.
$ free
total used free shared buffers cached
Mem: 8197800 1577300 6620500 0 4808 1516724
-/+ buffers/cache: 55768 8142032
Swap: 16386292 0 16386292
$ vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 0 0 5069748 10612 3014060 0 0 0 0 3 26 0 0 100 0
0 0 0 5069748 10612 3014060 0 0 0 0 4 22 0 0 100 0
0 0 0 5069748 10612 3014060 0 0 0 0 3 18 0 0 100 0
Measure the time of tar command.
$ ls -s test.dat
1501472 test.dat
$ time tar cvf test.tar test.dat
real 0m13.388s
user 0m0.116s
sys 0m5.304s
$ ./delayget -d -p <pid>
CPU count real total virtual total delay total
428 5528345500 5477116080 62749891
IO count delay total
338 8078977189
SWAP count delay total
0 0
RECLAIM count delay total
0 0
- When system is under heavy memory load
memory reclaim may occur.
$ vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 0 7159032 49724 1812 3012 0 0 0 0 3 24 0 0 100 0
0 0 7159032 49724 1812 3012 0 0 0 0 4 24 0 0 100 0
0 0 7159032 49848 1812 3012 0 0 0 0 3 22 0 0 100 0
In this case, one process uses more 8G memory
by execution of malloc() and memset().
$ time tar cvf test.tar test.dat
real 1m38.563s <- increased by 85 sec
user 0m0.140s
sys 0m7.060s
$ ./delayget -d -p <pid>
CPU count real total virtual total delay total
9021 7140446250 7315277975 923201824
IO count delay total
8965 90466349669
SWAP count delay total
3 21036367
RECLAIM count delay total
740 61011951153
In the later case, the value of RECLAIM is increasing.
So, taskstats can show how much memory reclaim influences TAT.
Signed-off-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujistu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
154 lines
4.0 KiB
C
154 lines
4.0 KiB
C
/* delayacct.h - per-task delay accounting
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*
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* Copyright (C) Shailabh Nagar, IBM Corp. 2006
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU General Public License for more details.
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*
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*/
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#ifndef _LINUX_DELAYACCT_H
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#define _LINUX_DELAYACCT_H
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#include <linux/sched.h>
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#include <linux/taskstats_kern.h>
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/*
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* Per-task flags relevant to delay accounting
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* maintained privately to avoid exhausting similar flags in sched.h:PF_*
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* Used to set current->delays->flags
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*/
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#define DELAYACCT_PF_SWAPIN 0x00000001 /* I am doing a swapin */
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#define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */
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#ifdef CONFIG_TASK_DELAY_ACCT
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extern int delayacct_on; /* Delay accounting turned on/off */
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extern struct kmem_cache *delayacct_cache;
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extern void delayacct_init(void);
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extern void __delayacct_tsk_init(struct task_struct *);
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extern void __delayacct_tsk_exit(struct task_struct *);
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extern void __delayacct_blkio_start(void);
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extern void __delayacct_blkio_end(void);
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extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
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extern __u64 __delayacct_blkio_ticks(struct task_struct *);
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extern void __delayacct_freepages_start(void);
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extern void __delayacct_freepages_end(void);
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static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
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{
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if (p->delays)
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return (p->delays->flags & DELAYACCT_PF_BLKIO);
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else
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return 0;
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}
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static inline void delayacct_set_flag(int flag)
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{
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if (current->delays)
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current->delays->flags |= flag;
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}
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static inline void delayacct_clear_flag(int flag)
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{
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if (current->delays)
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current->delays->flags &= ~flag;
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}
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static inline void delayacct_tsk_init(struct task_struct *tsk)
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{
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/* reinitialize in case parent's non-null pointer was dup'ed*/
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tsk->delays = NULL;
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if (delayacct_on)
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__delayacct_tsk_init(tsk);
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}
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/* Free tsk->delays. Called from bad fork and __put_task_struct
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* where there's no risk of tsk->delays being accessed elsewhere
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*/
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static inline void delayacct_tsk_free(struct task_struct *tsk)
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{
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if (tsk->delays)
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kmem_cache_free(delayacct_cache, tsk->delays);
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tsk->delays = NULL;
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}
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static inline void delayacct_blkio_start(void)
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{
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delayacct_set_flag(DELAYACCT_PF_BLKIO);
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if (current->delays)
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__delayacct_blkio_start();
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}
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static inline void delayacct_blkio_end(void)
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{
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if (current->delays)
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__delayacct_blkio_end();
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delayacct_clear_flag(DELAYACCT_PF_BLKIO);
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}
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static inline int delayacct_add_tsk(struct taskstats *d,
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struct task_struct *tsk)
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{
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if (!delayacct_on || !tsk->delays)
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return 0;
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return __delayacct_add_tsk(d, tsk);
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}
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static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
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{
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if (tsk->delays)
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return __delayacct_blkio_ticks(tsk);
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return 0;
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}
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static inline void delayacct_freepages_start(void)
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{
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if (current->delays)
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__delayacct_freepages_start();
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}
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static inline void delayacct_freepages_end(void)
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{
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if (current->delays)
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__delayacct_freepages_end();
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}
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#else
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static inline void delayacct_set_flag(int flag)
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{}
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static inline void delayacct_clear_flag(int flag)
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{}
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static inline void delayacct_init(void)
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{}
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static inline void delayacct_tsk_init(struct task_struct *tsk)
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{}
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static inline void delayacct_tsk_free(struct task_struct *tsk)
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{}
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static inline void delayacct_blkio_start(void)
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{}
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static inline void delayacct_blkio_end(void)
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{}
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static inline int delayacct_add_tsk(struct taskstats *d,
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struct task_struct *tsk)
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{ return 0; }
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static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
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{ return 0; }
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static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
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{ return 0; }
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static inline void delayacct_freepages_start(void)
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{}
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static inline void delayacct_freepages_end(void)
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{}
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#endif /* CONFIG_TASK_DELAY_ACCT */
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#endif
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