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authorKeika Kobayashi <kobayashi.kk@ncos.nec.co.jp>2008-07-25 01:48:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:47 -0700
commit873b47717732c2f33a4b14de02571a4295a02f0c (patch)
treeaaef0fe872dbd4ce5c290f3509e5db69f9a3f04a /kernel/delayacct.c
parent3e85ba034deec351f02cb55ff225bbd616463841 (diff)
downloadlinux-2.6.34-ux500-873b47717732c2f33a4b14de02571a4295a02f0c.tar.gz
per-task-delay-accounting: add memory reclaim delay
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>
Diffstat (limited to 'kernel/delayacct.c')
-rw-r--r--kernel/delayacct.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 10e43fd8b72..84b6782a2ce 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -165,3 +165,16 @@ __u64 __delayacct_blkio_ticks(struct task_struct *tsk)
return ret;
}
+void __delayacct_freepages_start(void)
+{
+ delayacct_start(&current->delays->freepages_start);
+}
+
+void __delayacct_freepages_end(void)
+{
+ delayacct_end(&current->delays->freepages_start,
+ &current->delays->freepages_end,
+ &current->delays->freepages_delay,
+ &current->delays->freepages_count);
+}
+