On 13/02/2019 17.39, Dave Howorth wrote:
On Wed, 13 Feb 2019 14:40:05 +0100 (CET) "Carlos E. R." <...@telefonica.net> wrote:
I then killed Firefox and Thunderbird, restarted them (the machine has to run my usual workload), then repeated the swapoff experiment.
Telcontar:~/Documents/lists/swapoff_test # time swapoff -a
real 3m30.374s user 0m0.001s sys 3m3.646s Telcontar:~/Documents/lists/swapoff_test #
I was writing my notes on the terminal, when the system *collapsed* and would not respond. I managed to issue "swapon -a" on an ssh session already opened on another machine, which took perhaps half an hour to process.
Yay! I'm happy you tried that trick and it worked :)
No, it did not work: it crashed, as I thought it would. But I said that I would try nonetheless and I did.
Then, with swap back on, the system responded, after also doing some OOM (on mysqld). Thunderbird was not running: ...
Interestingly, both mysqld and Thunderbird have been killed differently (one by oom-killer, another by oom_reaper) Why mysqld I have no idea, but it could have been worse.
mysqld is infamous for being chosen. oom-reaper is a relatively recent addition to the oom killer (from suse) There's a good discussion at https://lwn.net/Articles/668126/
[snip] TL;DR
Curious. Well, Thunderbird had an email in writing. I had to recover it from the draft folder.
As you can see, it is not possible to run this 8GiB machine without Swap - I said it would not work and I was right.
I think what you've proved is that the machine cannot support the workload. You either need to change the machine or the workload.
Neither is possible, unless I get donations ;-P I had to spend money on house repairs, crumbling walls and such. The washing machine refuses to tumble since this weekend, and the fridge controller module is dying - replacement is too expensive and not worth it on a 15 year machine. So I have to replace both machines. At the moment I have more pressing needs rather than replacing the motherboard + cpu + ram. The workload - well, Firefox has too many tabs and windows, which is why I asked about a tab archiver some weeks ago. The machine is very responsive using swap on SSD. After all, swap was invented decades ago precisely to avoid installing more RAM. The problem is some race condition that the current kernel doesn't handle well (the kernel in 42.3 did not have this problem). ]> Tasks: 448 total, 3 running, 444 sleeping, 0 stopped, 1 zombie ]> %Cpu(s): 14,5 us, 2,1 sy, 0,0 ni, 76,7 id, 6,7 wa, 0,0 hi, 0,0 si, 0,0 st ]> KiB Mem : 8161400 total, 712648 free, 5685608 used, 1763144 buff/cache ]> KiB Swap: 25165820 total, 23227900 free, 1937920 used. 1675796 avail Mem 1.6 GB available, that's good. Less than CPU 18% load. # uptime 19:49:46 up 8 days 5:55, 4 users, load average: 0.39, 0.65, 0.68
You might be able to find a browser that uses less memory (or tune FF), dunno. You might be able to find a way to work with less pages open.
You can almost certainly find a MUA that uses less memory then Thunderbird. My first thought is claws, of course :) But there are many other possibilities.
Not as user friendly. Yes, I also use Alpine. I need to see graphics and photos often.
Or you could move one or other process(es) to some other machine and remote the interface to your current machine, so it is merely serving as the display for that process.
No, but I can move some services to another machine, classical client-server setup. -- Cheers / Saludos, Carlos E. R. (from 15.0 x86_64 at Telcontar)