Swap space reduced?



  • Hi.

    I've discovered that swap space is "only" 32MB on my BQ E5 with OTA-5:

    $ free -m
                  total        used        free      shared  buff/cache   available
    Mem:            951         705          44           1         201         214
    Swap:            31          31           0
    phablet@ubuntu-phablet:~$ cat /proc/swaps 
    Filename                                Type            Size    Used    Priority
    /userdata/SWAP.img                      file            32764   32504   -1
    

    I feel pretty sure (thought I could be wrong) that swap was bigger, about 512MB, could that be the case that swap was reduced during OTA-4/5?

    I have noticed that after OTA-5, unity, browser and other webapps crashes more often. I thought maybe I get out of memory errors more often, and so I discovered swap space being only 32M.



  • Phones/tablets do not have much (if any) swap enabled by default, because flash based storage has a limited number of writes in its lifetime, and using swap on such storage can greatly reduce the lifespan of the storage when apps get shoved into swap.

    If you manually configured it to be larger previously, then that configuration very likely was replaced on update, especially if you were upgrading from 15.04, which would have resulted in a full image flash (so any modifications to rootfs would have been replaced).



  • I agree that swap can kill flash storage, but in current state, my phone is hardly usable.

    I did experiment:

    • Rebooted so that OS memory would be as clear as posible.
    • ssh'ed into it and watched free -m output - it started with about (only!) 270MB avaialble memory
    • Launched uNav, and kept scrolling as I if was driving.
    • After some time, available memory got down to tenths of megabytes, and whole Untiy crashed!

    I have these crashes when browsing with browser, or Reddit webapp, or similar. Just click on some link and boom - crash.

    Swap HAS to be much bigger on such small memory devices as BQ E5...

    I'll try to create bigger swap file and modify fstab to mount it...



  • Yep, no longer creashes. I see about ~180MB of swap spaces used up constantly, and uNav, Reddit webapp does not reproduce crash.




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