[ANNOUNCE] COMPCACHE on kernel-power (now with notifications) - Page 28 - maemo.org

patlak | # 271 | 2012-06-24, 22:49 | Report

Originally Posted by Raimu View Post

1) How much rootfs space have you got available? My first guess was that it might be getting low.
2) Are you quite sure this stops happening when you stop using compcache or µSD?
3) Which way do you start up the use of compcache/µSD now?

1. 63MB free
2. Back at eMMC virtual, haven't run into said error. If I do run into it, will let you know.
3. insmod; swapon/swapoff

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peterleinchen | # 272 | 2012-06-25, 11:10 | Report

Originally Posted by patlak View Post

Getting the following error in dmesg after certain amount of usage with both 64MB ramzswap and swap on SD enable. Also, happens when using only SD as swap.

Looks like some N900 do not like to be used without swap on eMMC!

I got some other strange issue when using only SD swap:
the UI froze (freezed?, not native speaker

) completely. Similar or maybe exactly like
https://bugs.maemo.org/show_bug.cgi?id=9150
http://talk.maemo.org/showthread.php?t=66660
, without sgx_misr eating all CPU. But Xorg consuming lots of CPU (saw it using ssh).

I had no clue what was going on and why, but afairc I had set my swap space to SD exclusively (compcache disabled since it was not of use to me). And this happened to me almost daily or more often.
Later on I switched back to have my SD swap on higher priority, but still have my eMMC swap on lower (default -1) priority. So it is used only for a few MB during startup and for refreshing my SD swap from time to time. Since then this did not occur anymore. Hopefully it is gone forever!
But still in testing phase ....

@patlak
Please report back about your experience. But maybe in SD swap thread, as it seems (at least for me and I read from your post, also for you) not to be related to compcache.

Last edited by peterleinchen; 2012-06-25 at 11:13.

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reinob | # 273 | 2012-06-26, 07:17 | Report

@peterleinchen,

That sounds weird, but at least for myself I cannot see the link between your frozen UI and swap on SD.

I use exclusively swap on SD since months and never had that symptom you describe. I normally only reboot the N900 once a month or so, and I've only "recycled" swap once, just for the fun of it.

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peterleinchen | # 274 | 2012-06-27, 22:18 | Report

Originally Posted by reinob View Post

@peterleinchen,

That sounds weird,

Exactly!

Originally Posted by reinob View Post

but at least for myself I cannot see the link between your frozen UI and swap on SD.

Me too

But I did not change anything else. And this was the only thing different, so just assuming such correlation here ...
(remember overclocking and stability of VDD options?)

I did a lot of research, but could not find any reason for this behavior, nor solution to above linked bugs.

Hopefully it is gone forever. At the moment it seems so.

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jurop88 | # 275 | 2012-06-30, 21:55 | Report

I have sometimes freezes and reboots while using swap on SD - IMHO it's something related to SD reliability and/or latency. When I need absolute stability I 'swapoff' the uSD partition, in all day usage I accept the risk and 'swapon' it again

peterleinchen | # 276 | 2012-06-30, 22:04 | Report

So third example for weird behaviour using only SD swap.

Did you try to set SD swap with higher priority and let emmc swap at original priority (EasyDebian or busybox-power: 'swapon -p 1 /dev/mmcblk1px')? Would be informative to know, if you still experience these freezes.

@any moderator:
would be nice to move these few last (an future) posts into the SD swap thread?

jurop88 | # 277 | 2012-07-02, 23:27 | Report

Originally Posted by peterleinchen View Post

So third example for weird behaviour using only SD swap.

Did you try to set SD swap with higher priority and let emmc swap at original priority (EasyDebian or busybox-power: 'swapon -p 1 /dev/mmcblk1px')? Would be informative to know, if you still experience these freezes.

@any moderator:
would be nice to move these few last (an future) posts into the SD swap thread?

replied here for continuity, feel free to open separate 'swap on SD thread'

usual conf is compcache -p15, mmcblk1p3 -p10, mmcblk0p3 -p1 and this way sometimes my N900 crashes. Never tried with SD with lower priority. I noticed that emmc swap is used also if priority is lower than SD swap. Is there a way to move data between swaps?

peterleinchen | # 278 | 2012-07-03, 17:41 | Report

Yes, for continuity I will also reply here.

I did not mean running SD swap with lower priority (would make no sense).
Your conf is OK. But using compcache caused lots of huge lags/freezes/reboots, so I do not use it at all anymore.

Usage of eMMC swap is due to startup usage, depending on how you start it (as early as possible with hacked rcS-late? or just as I do with an own event.d job?).
My ususal usage of eMMC is like that

Originally Posted by

~ $ cat /proc/swaps
Filename Type Size Used Priority
/dev/mmcblk0p3 partition 786424 4592 -1
/dev/loop7 partition 786424 24003 0

around 3-5 MB, but not increasing (else I do a swap refreshing of course).

What do you mean by "move data between swaps"?
A moving of data is not done:
Swaps with same priority are used on kernels decision (afaik), swap with higher priority is used, as long as not filled up completely, Second swap with lower priority will only be used, if first one floods over.
Maybe you mean a "refesh" to clean up one swap (defragmentation) as soon as data usage reaches swap size. Then you may enable second swap, disable first swap (all data is "moved"). And then ("maybe", as not obligatory) disable second swap again.

Last edited by peterleinchen; 2012-07-03 at 17:43.

jurop88 | # 279 | 2012-07-04, 22:12 | Report

Originally Posted by peterleinchen View Post

I did not mean running SD swap with lower priority (would make no sense).
Your conf is OK. But using compcache caused lots of huge lags/freezes/reboots, so I do not use it at all anymore.

For me, compcache works and I feel the speed/occasional lags tradeoff OK

Originally Posted by peterleinchen View Post

Usage of eMMC swap is due to startup usage, depending on how you start it (as early as possible with hacked rcS-late? or just as I do with an own event.d job?).

Currently I've swapset installed, so I think it sets swaps after start of Hildon-desktop

Originally Posted by peterleinchen View Post

What do you mean by "move data between swaps"?

I mean:
If data used 'often' are swapped in compcache, we could try to swap out 'old' data from compcache to 'real' swap in order to keep most used data in ram. I did not found any mechanism like that - and at a second glance it looks like it won't make sense in a desktop system where we don't have so many constraints and compressed file systems. I am currently using two smaller eMMC swaps instead of a big one, and it feels more laggy but with shorter lags. It is really hard to tell if there are differences without a test suite and with so many use cases.

davdav | # 280 | 2012-07-05, 03:39 | Report

how to make this work with kp50 ??
just guide me

thanks in advance