Re: devel/llvm13 failed to reclaim memory on 8 GB Pi4 running -current [correction to early claim]

[An explicit correction, with Mark Johnston included.]

On 2022-Jan-27, at 11:31, Mark Millard <marklmi@yahoo.com> wrote:

> On 2022-Jan-27, at 08:45, bob prohaska <fbsd@www.zefox.net> wrote:
> 
>> Attempts to compile devel/llvm13 on a Pi4 running -current (updated
>> on 20220126) with 8 GB of RAM and 8 GB of swap has failed on two occasions using 
>> make -DBATCH > make.log & 
>> in /usr/ports/devel/llvm13 using the system compiler. The system is
>> self-hosted. 
>> 
>> The first failure reported clang error 139, but the second
>> was different, reporting only:
>> FAILED: tools/flang/lib/Evaluate/CMakeFiles/obj.FortranEvaluate.dir/check-expression.cpp.o
>> along with a console report of
>> +swap_pager: indefinite wait buffer: bufobj: 0, blkno: 1258432, size: 4096
>> +swap_pager: indefinite wait buffer: bufobj: 0, blkno: 627221, size: 8192
>> +swap_pager: indefinite wait buffer: bufobj: 0, blkno: 240419, size: 4096
>> +swap_pager: out of swap space
> 
> In recent builds, such as yours, the above "out of swap" is a
> misnomer but is very interesting for what it is actually about.

Wrong: The message with the "swap_pager: " prefix is valid.
The misnomer messages do not have that prefix.

> . . .
> 
> Your context proves the metadata problem really happens, so
> the messaging should be fixed to not be misleading.
> 

Again wrong: My testing with monitoring every few seconds
indicates that the system is running out of swap, matching
the specific message that was generated.


I'm still running tests of the specific behavior for

vm.pfault_oom_attempts= -1 # done
vs.
vm.pfault_oom_attempts= 3
vm.pfault_oom_wait= 10

After that I intend runs with 30 GiBytes of swap (so RAM+SWAP 38 GiBytes).
Hopefully that will complete and I'll be able to report how much swap was
observed to have been used.


===
Mark Millard
marklmi at yahoo.com