On Sun, Mar 27, 2011 at 5:07 PM, KAMEZAWA Hiroyuki
[off-list ref] wrote:

On Sat, 26 Mar 2011 17:14:44 -0700
Ying Han [off-list ref] wrote:

quoted

Two new stats in per-memcg memory.stat which tracks the number of
page faults and number of major page faults.

"pgfault"
"pgmajfault"

It is valuable to track the two stats for both measuring application's
performance as well as the efficiency of the kernel page reclaim path.

Functional test: check the total number of pgfault/pgmajfault of all
memcgs and compare with global vmstat value:

$ cat /proc/vmstat | grep fault
pgfault 1070751
pgmajfault 553

$ cat /dev/cgroup/memory.stat | grep fault
pgfault 1069962
pgmajfault 553
total_pgfault 1069966
total_pgmajfault 553

$ cat /dev/cgroup/A/memory.stat | grep fault
pgfault 199
pgmajfault 0
total_pgfault 199
total_pgmajfault 0

Performance test: run page fault test(pft) wit 16 thread on faulting in 15G
anon pages in 16G container. There is no regression noticed on the "flt/cpu/s"

Sample output from pft:
TAG pft:anon-sys-default:
  Gb  Thr CLine   User     System     Wall    flt/cpu/s fault/wsec
  15   16   1     0.67s   232.11s    14.68s   16892.130 267796.518

$ ./ministat mmotm.txt mmotm_fault.txt
x mmotm.txt (w/o patch)
+ mmotm_fault.txt (w/ patch)
+-------------------------------------------------------------------------+
    N           Min           Max        Median           Avg        Stddev
x  10     16682.962     17344.027     16913.524     16928.812      166.5362
+  10      16696.49      17480.09     16949.143     16951.448     223.56288
No difference proven at 95.0% confidence

Signed-off-by: Ying Han <redacted>

Hmm, maybe useful ? (It's good to describe what is difference with PGPGIN)
Especially, you should show why this is useful than per process pgfault count.
What I thought of this, I thought that I need per-process information, finally...
and didn't add this.

Anyway, I have a request for the style of the function. (see below)

Thanks for your comment, and I will post V2 shortly.

quoted

---
 Documentation/cgroups/memory.txt |    4 +++
 fs/ncpfs/mmap.c                  |    2 +
 include/linux/memcontrol.h       |   22 +++++++++++++++
 mm/filemap.c                     |    1 +
 mm/memcontrol.c                  |   54 ++++++++++++++++++++++++++++++++++++++
 mm/memory.c                      |    2 +
 mm/shmem.c                       |    1 +
 7 files changed, 86 insertions(+), 0 deletions(-)

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index b6ed61c..2db6103 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt

@@ -385,6 +385,8 @@ mapped_file       - # of bytes of mapped file (includes tmpfs/shmem)

 pgpgin               - # of pages paged in (equivalent to # of charging events).
 pgpgout              - # of pages paged out (equivalent to # of uncharging events).
 swap         - # of bytes of swap usage
+pgfault              - # of page faults.
+pgmajfault   - # of major page faults.
 inactive_anon        - # of bytes of anonymous memory and swap cache memory on
              LRU list.
 active_anon  - # of bytes of anonymous and swap cache memory on active

@@ -406,6 +408,8 @@ total_mapped_file - sum of all children's "cache"

 total_pgpgin         - sum of all children's "pgpgin"
 total_pgpgout                - sum of all children's "pgpgout"
 total_swap           - sum of all children's "swap"
+total_pgfault                - sum of all children's "pgfault"
+total_pgmajfault     - sum of all children's "pgmajfault"
 total_inactive_anon  - sum of all children's "inactive_anon"
 total_active_anon    - sum of all children's "active_anon"
 total_inactive_file  - sum of all children's "inactive_file"

diff --git a/fs/ncpfs/mmap.c b/fs/ncpfs/mmap.c
index a7c07b4..adb3f45 100644
--- a/fs/ncpfs/mmap.c
+++ b/fs/ncpfs/mmap.c

@@ -16,6 +16,7 @@

 #include <linux/mman.h>
 #include <linux/string.h>
 #include <linux/fcntl.h>
+#include <linux/memcontrol.h>

 #include <asm/uaccess.h>
 #include <asm/system.h>

@@ -92,6 +93,7 @@ static int ncp_file_mmap_fault(struct vm_area_struct *area,

       * -- wli
       */
      count_vm_event(PGMAJFAULT);
+     mem_cgroup_pgmajfault_from_mm(area->vm_mm);

Could you do this as  mem_cgroup_count_vm_event(area->vm_mm, PGMAJFAULT) ?

will be included in V2.

<snip>

quoted

+void mem_cgroup_pgfault_from_mm(struct mm_struct *mm)
+{
+     struct mem_cgroup *mem;
+
+     if (!mm)
+             return;
+
+     rcu_read_lock();
+     mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+     if (unlikely(!mem))
+             goto out;
+     mem_cgroup_pgfault(mem, 1);
+
+out:
+     rcu_read_unlock();
+}
+
+void mem_cgroup_pgmajfault_from_mm(struct mm_struct *mm)
+{
+     struct mem_cgroup *mem;
+
+     if (!mm)
+             return;
+
+     rcu_read_lock();
+     mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+     if (unlikely(!mem))
+             goto out;
+     mem_cgroup_pgmajfault(mem, 1);
+out:
+     rcu_read_unlock();
+}
+EXPORT_SYMBOL(mem_cgroup_pgmajfault_from_mm);
+

Then, you can do above 2 in a function.

--Ying

Thanks,
-Kame

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