kernel 4.4 on Sailfish X
asked 2017-10-13 04:22:15 +0200
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- As Sony is bringing Android 8.0 Oreo on the Xperia F51xx.
- And Google is mandating Kernel version 4.4 for Oreo (because of hardening security features).
This means Sony will have a kernel 4.4 for their Xperia X F5121 hardware platform [as seen on the current unofficial AOSP test builds.
It would be awesome if Jolla could also provide this updated kernel in one of the next uprages of Sailfish X.
(This could potentially bring new extra security protections, and even a bunch of features introduced that the current 3.10 lacks)
update
Ressource :
- Sony's page with their progress on the official kernel 4.4 port
- Sony's github with their current kernel development
Also :
µSDXC fixes :
- Users report having problems with some µSDXC cards
- one TMO user reports consistently having the same card accepted by stock android, and completely unseen by Sailfish X
- One interesting answer points to known kernel bugs (which could explain why Up-to-date Android's 3.10.1xx kernel can detect the card, but Sailfish X's slightly older 3.10.84 misses it)
This kind of bugs would be a very good argument for Jolla to try to follow as closely as possible the updates that Sony makes available of their kernel for Xperia X.1
Meltdown & Spectre
As underlined by another request on TJC : according to ARM the Cortex-A72 core that is found inside Sony Xperia X' Snapdragon 650, is vulnerable to Spectre variation 1 (Bounds Check Bypass) and Spectre varation 2 (Branch Target Injection) - (And also a distant cousin of Meltdown Rogue Data Cache Load, that they call 3a, but one that doesn't require mitigation).
The various fixes will get merged eventually in the kernels that are still supported ( 3.18, 4.4 and 4.9 - versions considered still supported by Google ). But it's very unlikely that there will be efforts to bring them to older kernels (like the 3.10 that Sailfish X is currently using).
It's starting to look very urgent for Jolla to move Sailfish X to the newest Sony kernel.
again update
Jolla mentions coming updates for Sailfish including features that aren't supported by the current kernel, like BTRFS support. Which means they'll be considering at least some kernel update.
sailfish x 2.1.4
changelog mentions upgrade to kernel 3..10.108
My mistake, the correct package to check for is droid-hal-f5121-img-boot
. Which is still the exact same 3.10.84 version, only a new release (a new recompile, with the options mentioned by Jolla such as BTRFS enabled)
So still not 4.4 (and thus as release note reports, no little.BIG-aware scheduler yet) but at least the SD cards bugs should get fixed nor SD cards fixes either.
Let's hope 4.4 will be there for version 2.2.0
OOM killer on SFX 2.1.4
Note that the "out of memory killer" has been activated, to kill apps when ram usage is high.
RAM can be save by activating swap. Currently, kernel 3.10.84 only gives an "either/or" situation.
- Either you write you activate SWAP - as big as you want - on a flash media (SD card, or internal eMMC) but those don't like frequent writes (due to "write amplifications" - a write is actually implemented as a read of all the neighbors, an erase of the whole giant "erase block" and then rewrite everything).
- Or, you use "ZRAM" which makes a compressed RAM disc on which you can store swap, thus e.g.: you can reserve a small part of your RAM (say ~512MB) on which you can store swap (say ~1GB in case of good compression). Your flash is happy but this is swap is small (of course, as you're sacrificing RAM for it).
Kernel 4.4 would bring us Zswap :
- Basically compress swap like Zram, but can move the least often used pages to flash storage (giving both space and happy flash media).
- (Though in practice, it's a tiny bit more complicated under the hood : instead of a ram disk, it works as a compression pre-filter inside the regular Swap stack).
- Zswap is mainstream since kernel 3.11 - it's thus currently not available on current kernel 3.10.84, but could be compiled with upstream kernel 4.4 from Sony.
That would be fantastic. Being relegated to the (now ancient) 3.x world has been holding us all back.
deprecated ( 2017-10-13 08:07:17 +0200 )editLet‘s hope, this would come within the 1 year support we have
duque ( 2017-10-13 08:13:56 +0200 )edityes, please! It is the next LTS kernel for andriod.
jolladiho ( 2017-10-13 11:31:52 +0200 )editThis will probably also bring better support for the big.LITTLE CPU-Cores and therefore better user experience.
Cmdr_Zod ( 2017-11-15 23:46:44 +0200 )editkernel 3.2 is still maintained and will see Meltdown & Spectre fixes. KAISER and KPTI happened already in kernel 3.2.98. @DrYak no need to cry today... after May 2018 picture may be different with oldest still maintained LTS linux kernel being 3.16.x (Android-Kernel 3.10 will most likely still be maintained by Google)
lpr ( 2018-01-29 18:24:16 +0200 )edit