[meta-freescale] Right lib-imx/firmware-imx ... versions

[John Weber]

On 8/4/14, 2:04 PM, Jens Rehsack wrote:
> Am 04.08.2014 um 17:41 schrieb John Weber <rjohnweber at gmail.com>:
>
>> Hi Jens-
>>
>> On 8/2/14, 9:59 AM, Jens Rehsack wrote:
>>> Daiane, because you also was involved into https://community.freescale.com/thread/304414:
>>>
>>> I digged a lot deeper, tried https://github.com/wandboard-org/linux/commit/7cbd06b2904c1855109084ca6b0c84990bc69233
>>> and debugged and proved more there ...
>> Have you forward-ported this to 3.10.17?  If so, it seems that the only downside for this is that it preallocates a lot of memory for the VPU.  It really shouldn't be necessary as long as page caching works properly, as I understand it.
> Today we received a BSP for our board for 3.10.17 - we might try it after first field test lunch (we want to see applications running - so this is just a side-theater :)
> Important, but ... you know 8)
Yes - it would be good to see how this affects your system stability.  If it 
makes sense then perhaps we should have this integrated into the Wandboard kernel.
>>> I also tried to get a picture of vmm by browsing "Understanding The Linux Virtual Memory Manager" by Mel Gorman.
>>>
>>> My result: When no swap is configured (and the box has none - because of 1GB RAM and 4GB Flash there is not really space for swap), the memory runs full by page-caching disk files.
>> Are you seeing some error messages here that you can post?
> Precisely the same as in referred forum page - but IIRC a lot were posted earlier in the thread. I do not intend to spam list by reposting same information to often.
> If you want, I prepare you a pastebin :)
I'll see if I can dig back in the list.  Thanks.
>
>>> There could be several ways out to ensure system is not crashing when pages for DMA are allocated by eg. XBMC, gplay or whatever wants to use the VPU.
>>>
>>> 1) continuously drop page cache (our measurement tells in our configuration every 15sec is fine even for 4K movies)
>>> 2) implement better dma page cache as v4l2 patch demonstrates (pre-alloc 256M and serve dma pages from there, use smart allocation as SmartHeap does and https://github.com/wandboard-org/linux/commit/7cbd06b2904c1855109084ca6b0c84990bc69233 drafts ...)
>>> 3) modify vpu dma allocator to interfere with page cache and drop oldest cache entries
>>> 4) find a way to simulate swap-conditions without really paging out
>> This (4) seems like a hack.  We need to be able to turn off swap without having to simulate it.
> But we need to be able to kick cached pages when we need it - I'm quite unsure whether (4) is a hack or an improvement - why only swapping is permitted to drop caches?
Exactly.  I think you should be able to disable swap and still drop caches.