Re: More swap trouble with armv7, was Re: -current on armv7 stuck with flashing disk light
Date: Tue, 04 Jul 2023 21:51:24 UTC
[I continued to type MAX_JOBS_NUMBER where
MAKE_JOBS_NUMBER should have been what I
typed.]
On Jul 4, 2023, at 14:22, Mark Millard <marklmi@yahoo.com> wrote:
> On Jul 4, 2023, at 12:07, bob prohaska <fbsd@www.zefox.net> wrote:
>
>> On Tue, Jun 27, 2023 at 10:16:57AM -0700, bob prohaska wrote:
>>> On Tue, Jun 27, 2023 at 09:59:40AM -0700, Mark Millard wrote:
>>>>>
>>>>> If you want to identify system hangs, please
>>>>> put back:
>>>>>
>>>>> vm.swap_enabled=0
>>>>> vm.swap_idle_enabled=0
>>>>>
>>>
>>> They're reinstated now, but I don't want to disturb the system
>>> while it seems to be building world acceptably.
>>>
>> Reinstating
>> vm.swap_enabled=0
>> vm.swap_idle_enabled=0
>>
>> and limiting buildworld to -j3 allows buildworld to complete successfully in 1 GB of swap.
>>
>> Meanwhile, attempts to compile sysutils/usbtop using poudriere still cause swap exhaustion
>> while compiling /devel/llvm15 even with 2 GB of swap allocated.
>
> What sort of parallelism settings in poudriere for the
> devel/llvm15 build attempt? Have you tried allowing
> less parallelism (if there is a less for what you have
> tried)?
>
> What options are enabled vs. disabled for devel/llvm15 ?
>
> BE_STANDARD vs. BE_FREEBSD vs. BE_NATIVE ?
>
> BE_NATIVE probably help limit resource use the most if it
> happens to be sufficient. BE_FREEBSD would be in the
> middle of the 3 options for this issue.
>
> Is MLIR enabled? If having it disabled is sufficient, it
> being disabled should help avoid as much resource use.
> Simiarly for FLANG. (Building FLANG requires MLIR, so
> having MLIR disabled implies FLANG needing to also be
> disabled.)
>
>> The messages are
>> Jul 4 11:18:48 www kernel: pid 1074 (getty), jid 0, uid 0, was killed: out of swap space
>
> In my view the "out of swap space" is still a misleading
> misnomer for this context, but at least the following
> messages are more specific to the actual internal
> data-structure(s) problem(s). My understanding is that
> the data structures can have fragmentation issues.
>
> For fragmentation issues, prior history since booting
> might contribute, and building just after a reboot may
> end up with less fragmentation. (Unknown if sufficiently
> less.)
>
> Also, over allocating the swap partition (by not having
> kern.maxswzone appropriately matching) likely makes
> "swap blk zone exhausted" more likely. It is one of the
> reasons I avoid using swap partitioning with a total
> size that generates the message about possible
> mistuning.
>
>> swap blk zone exhausted, increase kern.maxswzone
>
> Have you ever gotten the above line before? I was
> unaware of any examples of it showing up.
>
>> swblk zone ok
>
> I'll note that there is another potential message
> pair for "swap pctrie zone exhausted"/"swpctrie zone ok"
> that you have not reported getting.
>
> Have you ever seen the "swap pctrie zone exhausted"
> notice? (Just curiosity on my part.)
>
>> IIRC the "increase kern.maxswzone" is unhelpful, if not impossible. The
>> "swblk zone ok" seems new.
>
> Are you using the default kern.maxswzone for your context?
> What is its value?
>
> Did you get the notice about possible mistuning for your
> combination of swap partition sizing and kern.maxswzone
> value? Or did "swap blk zone" happen even without that
> notice happening?
>
>> From the gstat output near peak swap use the system wasn't I/O bound,
>
> The "swap blk zone" contains an in-kernel-RAM data
> structure that is involved in managing the swap space
> usage.
>
>> the disk was less than 25% busy at the time of the first OOMA kill.
>
> "swap blk zone" can end up with fragmentation issues, where
> the total available is only made up of a bunch of tiny chunks
> and nothing large can be handled as a unit any more. (A general
> description of "fragmented".)
>
>> Eventually it was possible to log in on the serial console and run top:
>>
>> 33 processes: 1 running, 29 sleeping, 3 zombie
>> CPU: 0.0% user, 0.0% nice, 10.6% system, 0.2% interrupt, 89.2% idle
>> Mem: 139M Active, 8256K Inact, 252M Laundry, 221M Wired, 98M Buf, 292M Free
>> Swap: 2048M Total, 1291M Used, 756M Free, 63% Inuse
>>
>> PID JID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
>> 40719 0 root 1 20 -20 0B 8192B swzonx 0 0:12 9.15% cron
>> 40717 0 root 1 20 -20 0B 8192B swzonx 0 0:34 9.08% sh
>> 40709 0 root 1 20 -20 0B 8192B swzonx 0 0:38 9.01% sshd
>> 40720 0 root 1 20 -20 0B 8192B swzonx 3 0:13 7.47% sh
>
> Unfortunately the swzonx text is truncated. There is
> actually:
>
> pause("swzonxb", 10); for swblk zone
> and:
> pause("swzonxp", 10); for swap pctrie zone
>
> top's display leaves it unclear which was involved.
>
>> 40721 0 bob 1 20 0 6608K 2600K CPU1 1 0:00 0.32% top
>> 25761 0 bob 1 20 0 14M 6136K select 0 0:02 0.03% sshd
>> 25852 0 root 1 20 0 4668K 1648K ttyin 1 0:01 0.03% tip
>> 1237 0 root 1 20 0 5820K 1540K wait 1 0:12 0.00% sh
>> 25381 0 root 1 23 0 14M 5868K select 1 0:01 0.00% sshd
>> 1030 0 root 1 24 0 13M 2416K vmbckw 1 0:00 0.00% sshd
>> 12715 0 root 1 68 0 5820K 1660K wait 0 0:00 0.00% sh
>> 12710 0 root 1 20 0 5820K 1556K piperd 1 0:00 0.00% sh
>> 929 0 root 1 20 0 5356K 1256K select 3 0:00 0.00% syslogd
>> 1014 0 root 1 20 0 5124K 1356K nanslp 2 0:00 0.00% cron
>> 25770 0 bob 1 36 0 6844K 3116K pause 1 0:00 0.00% tcsh
>> 25794 0 bob 1 24 0 5380K 2188K wait 2 0:00 0.00% su
>> 39626 0 root 1 20 0 5424K 2404K wait 2 0:00 0.00% login
>> 40635 0 bob 1 20 0 6824K 3272K pause 1 0:00 0.00% tcsh
>> 25820 0 root 1 21 0 5608K 2204K wait 0 0:00 0.00% sh
>> 25851 0 root 1 20 0 4668K 1656K ttyin 3 0:00 0.00% tip
>> 40454 0 root 1 24 0 4636K 1780K ttyin 3 0:00 0.00% getty
>>
>> I'll let it go for a while to see if poudriere notices it's failed and cleans up.
>>
>> At the moment /boot/loader.conf contains
>>
>> # Configure USB OTG; see usb_template(4).
>> hw.usb.template=3
>> umodem_load="YES"
>> # Disable the beastie menu and color
>> beastie_disable="YES"
>> loader_color="NO"
>> vm.pageout_oom_seq="4096"
>> vm.pfault_oom_attempts="3"
>> vm.pfault_oom_attempts="120"
>
> 2 assignments to the same thing in a row?
> The 2nd ends up controlling the value.
>
>> vm.pfault_oom_wait="20"
>
> So you are allowing it 120 * 20 sec == 2400 sec
> (in other words, 40 minutes of retrying every 20
> seconds) to handle a page fault.
>
> That time scale may have contributed to why it
> failed first for "swap blk zone exhausted"
> instead of more usual types of OOM cause:
> How many page faults had active 40 minute
> intervals at the time?
>
> You may be just moving around where a problem
> shows up, not leading to lack of a failure
> overall.
>
>> kern.cam.boot_delay="20000"
>> vfs.ffs.dotrimcons="1"
>> vfs.root_mount_always_wait="1"
>> filemon_load="YES"
>>
>> /usr/local/etc/poudriere.conf contains
>> USE_TMPFS=no
>> NOHANG_TIME=28800
>> MAX_EXECUTION_TIME_EXTRACT=14400
>> MAX_EXECUTION_TIME_INSTALL=14400
>> MAX_EXECUTION_TIME_PACKAGE=432000
>> ALLOW_MAKE_JOBS=yes
>> MAX_JOBS_NUMBER=2
>
> I do not remember there being a MAX_JOBS_NUMBER in
> the infrastructure. So I will ignore that line. It
> probably should be deleted.
>
>> MAKE_JOBS_NUMBER=2
>>
>> Do these settings look reasonable?
>
> ALLOW_MAKE_JOBS/MAX_JOBS_NUMBER is not independent
> of what is being built. There is no global, single
> answer to "looks reasonable" for them.
Sorry: ALLOW_MAKE_JOBS/MAKE_JOBS_NUMBER
> However, MAX_JOBS_NUMBER is in the wrong file.
Sorry: MAKE_JOBS_NUMBER
> It is from/for make, not from/for poudriere
> directly. (But there is a way for poudriere
> to contribute such to make.)
>
> For example (from a grep):
>
> /usr/local/etc/poudriere.d/make.conf:MAKE_JOBS_NUMBER=2
>
> ( MAKE_JOBS_NUMBER_LIMIT is the same for where it
> goes. )
>
> You might need to use MAX_JOBS_NUMBER=1 or
Sorry yet again: MAKE_JOBS_NUMBER
> to not assign to ALLOW_MAKE_JOBS to have a
> chance to have the devel/llvm15 build fit
> if you have already turned off options that
> avoid using resources for building what you
> do not need.
>
===
Mark Millard
marklmi at yahoo.com