Date: Fri, 03 Aug 2018 21:11:42 +0200 From: Mark Martinec <Mark.Martinec+freebsd@ijs.si> To: stable@freebsd.org Cc: Mark Johnston <markj@freebsd.org> Subject: Re: All the memory eaten away by ZFS 'solaris' malloc - on 11.1-R amd64 Message-ID: <b3aa2bbe947914f8933b24cf0d0b15f0@ijs.si> In-Reply-To: <2ec91ebeaba54fda5e9437f868d4d590@ijs.si> References: <1a039af7758679ba1085934b4fb81b57@ijs.si> <3e56e4de076111c04c2595068ba71eec@ijs.si> <20180731220948.GA97237@raichu> <2ec91ebeaba54fda5e9437f868d4d590@ijs.si>
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More attempts at tracking this down. The suggested dtrace command does
usually abort with:
Assertion failed: (buf->dtbd_timestamp >= first_timestamp),
file
/usr/src/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c,
line 3330.
but with some luck soon after each machine reboot I can leave the dtrace
running for about 10 or 20 seconds (max) before terminating it with a
^C,
and succeed in collecting the report. If I miss the opportunity to
leave
dtrace running just long enough to collect useful info, but not long
enough for it to hit the assertion check, then any further attempt
to run the dtrace script hits the assertion fault immediately.
Btw, (just in case) I have recompiled kernel from source
(base/release/11.2.0)
with debugging symbols, although the behaviour has not changed:
FreeBSD floki.ijs.si 11.2-RELEASE FreeBSD 11.2-RELEASE #0 r337238:
Fri Aug 3 17:29:42 CEST 2018
mark@xxx.ijs.si:/usr/obj/usr/src/sys/FLOKI amd64
Anyway, after several attempts I was able to collect a useful dtrace
output from the suggested dtrace stript:
# dtrace -n 'dtmalloc::solaris:malloc {@allocs[stack(), args[3]] =
count()} dtmalloc::solaris:free {@frees[stack(), args[3]] = count()}'
while running "zpool list" repeatedly in another terminal screen:
# (while true; do zpool list -Hp >/dev/null; vmstat -m | fgrep
solaris; \
sleep 0.2; done) | awk '{print $2-a; a=$2}'
454303
570
570
570
570
570
570
570
570
570
570
570
570
570
570
Two samples of the collected dtrace output (after about 15 seconds)
are at:
https://www.ijs.si/usr/mark/tmp/dtrace1.out.bz2
https://www.ijs.si/usr/mark/tmp/dtrace2.out.bz2
(the dtrace2.out is probably cleaner, I made sure no other service
was running except my sshd and syslog)
Not really sure what I'm looking at, but a couple of large entries
stand out:
$ awk '/^ .*[0-9]+ .*[0-9]$/' dtrace2.out | sort -k1n | tail -5
114688 138
114688 138
114688 138
114688 138
114688 138
Thanks in advance for looking into it,
Mark
2018-08-01 09:12, myself wrote:
>> On Tue, Jul 31, 2018 at 11:54:29PM +0200, Mark Martinec wrote:
>>> I have now upgraded this host from 11.1-RELEASE-p11 to 11.2-RELEASE
>>> and the situation has not improved. Also turned off all services.
>>> ZFS is still leaking memory about 30 MB per hour, until the host
>>> runs out of memory and swap space and crashes, unless I reboot it
>>> first every four days.
>>>
>>> Any advise before I try to get rid of that faulted disk with a pool
>>> (or downgrade to 10.3, which was stable) ?
>
> 2018-08-01 00:09, Mark Johnston wrote:
>> If you're able to use dtrace, it would be useful to try tracking
>> allocations with the solaris tag:
>>
>> # dtrace -n 'dtmalloc::solaris:malloc {@allocs[stack(), args[3]] =
>> count()} dtmalloc::solaris:free {@frees[stack(), args[3]] =
>> count();}'
>>
>> Try letting that run for one minute, then kill it and paste the
>> output.
>> Ideally the host will be as close to idle as possible while still
>> demonstrating the leak.
>
> Good and bad news:
>
> The suggested dtrace command bails out:
>
> # dtrace -n 'dtmalloc::solaris:malloc {@allocs[stack(), args[3]] =
> count()} dtmalloc::solaris:free {@frees[stack(), args[3]] = count();}'
> dtrace: description 'dtmalloc::solaris:malloc ' matched 2 probes
> Assertion failed: (buf->dtbd_timestamp >= first_timestamp), file
> /usr/src/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c,
> line 3330.
> Abort trap
>
> But I did get one step further, localizing the culprit.
>
> I realized that the "solaris" malloc count goes up in sync with
> the 'telegraf' monitoring service polls, which also has a ZFS plugin
> which monitors the zfs pool and ARC. This plugin runs 'zpool list -Hp'
> periodically.
>
> So after stopping telegraf (and other remaining services),
> the 'vmstat -m' shows that InUse count for "solaris" goes up by 552
> every time that I run "zpool list -Hp" :
>
> # (while true; do zpool list -Hp >/dev/null; vmstat -m | \
> fgrep solaris; sleep 1; done) | awk '{print $2-a; a=$2}'
> 6664427
> 541
> 552
> 552
> 552
> 552
> 552
> 552
> 552
> 552
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