linux/mm
Keika Kobayashi 873b477177 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>
2008-07-25 10:53:47 -07:00
..
allocpercpu.c Merge commit 'v2.6.26-rc9' into cpus4096 2008-07-06 14:23:39 +02:00
backing-dev.c mm: bdi: fix race in bdi_class device creation 2008-05-20 13:31:53 -07:00
bootmem.c bootmem: replace node_boot_start in struct bootmem_data 2008-07-24 10:47:20 -07:00
bounce.c
dmapool.c dmapool: enable debugging for CONFIG_SLUB_DEBUG_ON too 2008-04-28 08:58:20 -07:00
fadvise.c xip: support non-struct page backed memory 2008-04-28 08:58:23 -07:00
filemap_xip.c xip: support non-struct page backed memory 2008-04-28 08:58:23 -07:00
filemap.c memcg: remove refcnt from page_cgroup 2008-07-25 10:53:37 -07:00
fremap.c mm: fix various kernel-doc comments 2008-03-19 18:53:35 -07:00
highmem.c highmem: Export totalhigh_pages. 2008-07-19 22:39:46 -07:00
hugetlb.c hugetlb: quota is not freed for unused reserved private huge pages 2008-07-24 10:47:19 -07:00
internal.h mm: export prep_compound_page to mm 2008-07-24 10:47:17 -07:00
Kconfig mm: make CONFIG_MIGRATION available w/o CONFIG_NUMA 2008-07-24 10:47:21 -07:00
maccess.c kgdb: fix optional arch functions and probe_kernel_* 2008-04-17 20:05:39 +02:00
madvise.c xip: support non-struct page backed memory 2008-04-28 08:58:23 -07:00
Makefile mm: remove mm_init compilation dependency on CONFIG_DEBUG_MEMORY_INIT 2008-07-24 10:47:17 -07:00
memcontrol.c memcg: limit change shrink usage 2008-07-25 10:53:37 -07:00
memory_hotplug.c memory-hotplug: add sysfs removable attribute for hotplug memory remove 2008-07-24 10:47:21 -07:00
memory.c hugetlb: introduce pud_huge 2008-07-24 10:47:18 -07:00
mempolicy.c hugetlb: modular state for hugetlb page size 2008-07-24 10:47:17 -07:00
mempool.c
migrate.c memcg: remove refcnt from page_cgroup 2008-07-25 10:53:37 -07:00
mincore.c mm: remove nopage 2008-04-28 08:58:18 -07:00
mlock.c
mm_init.c mm: create /sys/kernel/mm 2008-07-24 10:47:17 -07:00
mmap.c hugetlb: modular state for hugetlb page size 2008-07-24 10:47:17 -07:00
mmzone.c mm: filter based on a nodemask as well as a gfp_mask 2008-04-28 08:58:19 -07:00
mprotect.c mm: record MAP_NORESERVE status on vmas and fix small page mprotect reservations 2008-07-24 10:47:16 -07:00
mremap.c
msync.c
nommu.c nommu: Correct kobjsize() page validity checks. 2008-06-12 07:56:17 -07:00
oom_kill.c oom_kill: remove unused parameter in badness() 2008-04-28 08:58:26 -07:00
page_alloc.c memory hotplug: small fixes to bootmem freeing for memory hotremove 2008-07-24 10:47:21 -07:00
page_io.c mm: fix PageUptodate data race 2008-02-05 09:44:19 -08:00
page_isolation.c
page-writeback.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2008-07-15 08:36:38 -07:00
pagewalk.c pagemap: pass mm into pagewalkers 2008-06-12 18:05:41 -07:00
pdflush.c pdflush: use time_after() instead of open-coding it 2008-07-25 10:53:28 -07:00
prio_tree.c
quicklist.c
readahead.c mm: bdi: export BDI attributes in sysfs 2008-04-30 08:29:49 -07:00
rmap.c memcg: remove refcnt from page_cgroup 2008-07-25 10:53:37 -07:00
shmem_acl.c
shmem.c memcg: helper function for relcaim from shmem. 2008-07-25 10:53:37 -07:00
slab.c Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
slob.c slob: record page flag overlays explicitly 2008-07-24 10:47:15 -07:00
slub.c slub: record page flag overlays explicitly 2008-07-24 10:47:15 -07:00
sparse-vmemmap.c Christoph has moved 2008-07-04 10:40:04 -07:00
sparse.c memory hotplug: allocate usemap on the section with pgdat 2008-07-24 10:47:21 -07:00
swap_state.c mm: bdi: add separate writeback accounting capability 2008-04-30 08:29:50 -07:00
swap.c mm: remove initialization of static per-cpu variables 2008-07-24 10:47:21 -07:00
swapfile.c mm: fix ever-decreasing swap priority 2008-07-24 10:47:21 -07:00
thrash.c
tiny-shmem.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2008-03-25 08:57:47 -07:00
truncate.c fix invalidate_inode_pages2_range() to not clear ret 2008-04-28 08:58:18 -07:00
util.c
vmalloc.c vmallocinfo: add NUMA information 2008-07-24 10:47:17 -07:00
vmscan.c per-task-delay-accounting: add memory reclaim delay 2008-07-25 10:53:47 -07:00
vmstat.c mm/vmstat.c: proper externs 2008-07-24 10:47:14 -07:00