Thread: [SFOS][1.1.0.27][OOM] The death of multitasking?
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MartinK is offline MartinK
2014-12-26 , 13:14
Posts: 1,548 | Thanked: 7,510 times | Joined on Apr 2010 @ Czech Republic
#29
Originally Posted by Manatus View Post
Zram comes now preinstalled. After commenting out zramswapon line in

/lib/systemd/system/zram.service

and rebooting I seem to get that extra 100 MB back. It seemed to me that just disabling that service does not work out.

Now I really need both Android Firefox and Sailfish Browser have big pages open until OOM starts its crusade.
Well, you did not really get it back - you lost up to 200 MB. Zram kicks in before the real swap starts to be used and can usually achieve an up to 50% compression ratio. So a 100 MB zram volume can give you up to 200 MB in-RAM space - basically an extra 100 MB of still fast RAM.

Actually I wonder if that new fancy OOM killer actually takes zram properly into account, as using it should not lead to any noticeable slowdowns. If would be very very wrong if it just lumps it together with normal swap when calculating if it should kill something.

Also, the zram volume size (actually 2x50 MB so that both CPU cores can be used for compression) seems kinda small compared to overall ram size - it is usually advised to use a much bigger amount of ram for zram. Even the N9 that also had just 1 GB of RAM used 256 MB for zram (still called compcache back then - see these nice slides about compcache usage on the N9 and N900).

So I would advice trying to make the overall zram volume size larger to see if it helps with the OOM situation.
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