On Thu, Sep 28, 2017 at 9:19 PM, Ruslan Ruslichenko -X (rruslich -
GLOBALLOGIC INC at Cisco) <rrusl...@cisco.com> wrote:
> Hi Johannes,
>
> Hopefully I was able to rebase the patch on top v4.9.26 (latest supported
> version by us right now)
> and test a bit.
> The overall idea definitely looks promising, although I have one question on
> usage.
> Will it be able to account the time which processes spend on handling major
> page faults
> (including fs and iowait time) of refaulting page?
>
> As we have one big application which code space occupies big amount of place
> in page cache,
> when the system under heavy memory usage will reclaim some of it, the
> application will
> start constantly thrashing. Since it code is placed on squashfs it spends
> whole CPU time
> decompressing the pages and seem memdelay counters are not detecting this
> situation.
> Here are some counters to indicate this:
>
> 19:02:44 CPU %user %nice %system %iowait %steal %idle
> 19:02:45 all 0.00 0.00 100.00 0.00 0.00 0.00
>
> 19:02:44 pgpgin/s pgpgout/s fault/s majflt/s pgfree/s pgscank/s
> pgscand/s pgsteal/s %vmeff
> 19:02:45 15284.00 0.00 428.00 352.00 19990.00 0.00 0.00
> 15802.00 0.00
>
> And as nobody actively allocating memory anymore looks like memdelay
> counters are not
> actively incremented:
>
> [:~]$ cat /proc/memdelay
> 268035776
> 6.13 5.43 3.58
> 1.90 1.89 1.26
>
> Just in case, I have attached the v4.9.26 rebased patched.
>
Looks like this 4.9 version does not contain the accounting in lock_page.
