linaro-kernel

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10094 discussions

[ACTIVITY] (Anton Vorontsov) 2012-02-13 - 2012-02-17

by Anton Vorontsov

== Highlights == * Further work on familiarizing with the scheduler code. * Built and tried cpufreq-bench, but the suite reported that it'll take more then 6 hours to complete. I hope it's some bug in the cpufreq-bench, but didn't investigate it yet. * Got some notes/concerns regarding idea of moving LMK to the userland. The problem is that we should make sure that LMK would not need any new allocations, which seems nearly impossible in JVM. The idea to solve the issue would be to move killer process into the C code (as a daemon), and then revert Activity Manager to handle oom_adj. Upon low-memory event, the killer would just read pid's oom_adj. This will be good for a proof-of-concept thing (and as a drop-in replacement for the LMK kernel driver), but for production, we might want Activity Manager to keep process list in a shared memory (+ maybe liburcu for efficiency). This whole scheme seems even better then having everything in Java (as we won't need cgroups/low-memory-notifiers bindings). -- Anton Vorontsov Email: cbouatmailru(a)gmail.com

13 years, 2 months

[ACTIVITY] (Anton Vorontsov) 2012-02-06 - 2012-02-10

by Anton Vorontsov

== Highlights == * Submitted interactive cpufreq governor, got a lot of feedback. Mostly about cpufreq in general, and that we should make scheduler more PM-aware instead on making cpufreq itself scheduler-state aware. Fiddling with the scheduler is surely a lot of fun, so I started looking into entity load-tracking re-work patches by Paul Turner @ Google. As Peter Zijlstra says, these patches should be a good start to add avg runtime per cpu. * Further work on a patchset that fixes various task->mm handling mistakes. More abusers found and fixed. (This is started as a LMK cleanup, but as it appears a lot of other code in the kernel has the same bugs.) * Several LMK fixes were accepted into -staging. -- Anton Vorontsov Email: cbouatmailru(a)gmail.com

13 years, 2 months

[ACTIVITY] (John Stultz) Feb 11-17

by John Stultz

=== Highlights === * Rebased the 3.2 Androidization patches from Andy Green onto 3.3-rc3 and provided them to Andrey for the 12.2 release. * Worked to get Rafael's wakelock patches into a git tree for testing. Unfortunately the patches have been under quite a bit of churn on the list, so I asked Rafael for a git tree to pull from, but he's not yet responded. * Pinged tglx on my patch queues for 3.4, and he pulled them in. * Spent some time trying to get a test platform working to play with Rafael's wakelock patches. So far there seems to be an issue getting the panda board to notice wake-events after suspending. * Finished a first rough draft summarizing Android upstreaming meeting from last week. The hope is to publish it to lwn once complete. * Tried to address a number of comments on the fadvise volatile patches. Integrated a few fixes to issues noticed by reviewers, and proposed using a different interface if folks feel fadvise isn't appropriate. Found an ugly locking issue I need to solve. * Handled some Android-subteam items. === Plans === * Finish summary writeup and send to lwn * Read over other fadvises discussions going on, and review interval kinterval tree implementation sent out by Andrea Righi. * Read more on the pagecache code, and try to take another pass at fadvise volatile code. === Issues === * NA

13 years, 2 months

[ACTIVITY][weekly][linaro] (Dave Martin) 2012-01-30 - 2012-02-17

by Dave Martin

[ACTIVITY][weekly][linaro] (Dave Martin) 2012-01-30 - 2012-02-17 == Dave Martin <dmart> == === Activity Summary === * big.LITTLE switcher bringup on the ARM model to be delivered to Linaro (builds; mostly, but not completely, working) * Linaro Connect * Started hacking some patches to enter the kernel in HYP mode to allow the kernel to install its own hypervisor code at run-time -- potentially of interest to the big.LITTLE and KVM folks. -> git://git.linaro.org/people/dmart/linux-3-arm.git arm/hyp-entry+zImage-bounce-hacks (zImage decompressor runs mostly in SVC mode, appears to work, but the zImage hacks are fundamentally flawed and may not work on real hardware) -> git://git.linaro.org/people/dmart/linux-3-arm.git arm/hyp-entry+lpae (zImage decompressor runs natively in hyp mode -- currently extremely incomplete and out of sync with the other branches) -> git://git.linaro.org/people/dmart/boot-wrapper.git hyp-entry/fixes (fixes on top of Rusty's boot-wrapper required for actually testing the above branches on the model) This work is not posted upstream yet: the plan is to get a sane implementation and a reasonably clean patch series before posting an upstream RFC. === Plans === * Sync the various arm/hyp-entry branches and cleanly separate the main kernel stuff from the zImage decompressor stuff * Address the various comments received so far. * Modify the in-kernel hypervisor stub just to provide a raw "jump to this address in hyp mode" call instead of a cooked "set hypervisor vectors" call. This is closer to Christoffer Dall's existing implementation for KVM, and is both simpler and more flexible than my current approach. * Clean up main kernel patches and post upstream RFC. * Get the zImage decompressor working in hyp mode; post for review. * Draft initial specification for the big.LITTLE implementation details within Linaro, and flesh out the blueprint. * Finish debugging the GNU-ised ARM switcher on the A15+A7 model. === Work Items === no update === Absences === none planned yet

13 years, 2 months

SPI driver issue in Linux kernel3.0.8 ~ - Ask Linaro

by Michael Opdenacker

Greetings, There's a question on Ask Linaro, about a driver that worked in 2.6.35, but stopped working in 3.0.8: http://ask.linaro.org/questions/727/spi-driver-issue-in-linux-kernel308 Don't hesitate to share any advise and tips with the guy, Thanks in advance, Cheers, Michael. -- Michael Opdenacker - Community Manager Linaro, http://linaro.org Phone: +33 484 253 396 IRC: 'opm' in #linaro on irc.freenode.net

13 years, 2 months

[ACTIVITY] (John Stultz) Feb 6-10

by john stultz

=== Highlights === * Attended Linaro Connect. Now a bit exhausted. :) * Presented on merge_config.sh script. Interesting discussion around how even within linaro we have a variety of build systems with which we will have to integrate the concept of config fragments. The question of who maintains the fragments is still somewhat open, but hopefully we can centralize their location in the linaro kernel source maintained by Andrey. Two interesting suggestions were to have something like a source command in config fragments, as well as some commented out annotation in the resulting config. Will have to look into these in the future. * Dropped by the Android workgroup room and worked with Vishal and Amit on the Android team to get the origen fb console working with software rendering under Android. It was great to go into the Android room and get really useful help in working out what the problems were. This was really useful for Demo Friday, and great example of the benefit of attending Linaro Connect. * Had some discussions as well as attended talks about plans for Android's ion infrastructure. There seems to be a fair amount of community interest in it, but from the Google folks' comments, it seems like it may have a fair amount of churn in the future, so it may not be best to upstream it yet. Having some point for community discourse and collaboration (if not a centralized merge point) is needed. * Re-sent android-alarm driver to GregKH for staging, as he had some last minute requests on minor patch ordering issues. * Resolved the last few bugs I could trigger with my range-tree implementation of fadvise volatile code. Sent out to lkml for review. So far only minor comments, but I did get some mail today on a different but related fadvise effort that is also using range data. * Attended the Android upstreaming effort community face to face meeting organized by Tim Bird. It was ~4 hours and covered a lot of material. Very positive interaction overall with the Google folks. They seem to be in agreement with most of our approaches, and where they disagreed they were not dismissive, and were open to us still prototyping and trying to convince them otherwise. * Demoed the origen board running Android on a vanilla linus' HEAD 3.3-rc kernel with only two minor patches. Repeated myself endlessly to probably everyone. === Plans === * Need to summarize and organize my thoughts from the week, and catch up on some Android Kernel Subteam items. * Plan on closer review of Rafael's wakelock patches that were sent out and try to integrate them with the android alarm timers work in staging. * Read over other fadvises discussions going on, and review interval kinterval tree implementation sent out by Andrea Righi. * Take another pass at fadvise volatile code. * Ping tglx on 3.4 queue. === Issues === * NA

13 years, 2 months

[PATCH] staging: android/lowmemorykiller: Don't grab tasklist_lock

by Anton Vorontsov

Grabbing tasklist_lock has its disadvantages, i.e. it blocks process creation and destruction. If there are lots of processes, blocking doesn't sound as a great idea. For LMK, it is sufficient to surround tasks list traverse loop with rcu_read_{,un}lock() pair. Suggested-by: Oleg Nesterov <oleg(a)redhat.com> Signed-off-by: Anton Vorontsov <anton.vorontsov(a)linaro.org> --- Also thanks to Eric and Paul for the ideas. drivers/staging/android/lowmemorykiller.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c index 2d8d2b7..b3ade2f 100644 --- a/drivers/staging/android/lowmemorykiller.c +++ b/drivers/staging/android/lowmemorykiller.c @@ -34,6 +34,7 @@ #include <linux/mm.h> #include <linux/oom.h> #include <linux/sched.h> +#include <linux/rcupdate.h> #include <linux/profile.h> #include <linux/notifier.h> @@ -132,7 +133,7 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) } selected_oom_adj = min_adj; - read_lock(&tasklist_lock); + rcu_read_lock(); for_each_process(p) { struct mm_struct *mm; struct signal_struct *sig; @@ -185,7 +186,7 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) } lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n", sc->nr_to_scan, sc->gfp_mask, rem); - read_unlock(&tasklist_lock); + rcu_read_unlock(); return rem; } -- 1.7.7.6

13 years, 2 months

[ACTIVITY] (Anton Vorontsov) 2012-01-30 - 2012-02-03

by Anton Vorontsov

== Highlights == * Deep dive into signal/clone/exit handling to better understand current LMK technical flaws. As a side effect noticed a lot of other bugs (not only in LMK). * Further investigation on interactive cpufreq dependencies. Looking into various CPU idle notifiers, PM callbacks and cpuidle stuff. This is all parts of proper handling of cpufreq interactive governor. (Well, now it appears that idle notifiers are no good, as scheduler might provide a per-cpu load avg values, which, if accurate enough, might be a suitable replacement.) * Got not much time to continue LMK-userland stuff, though. But this is still near the top of my 'interesting things to do' list. -- Anton Vorontsov Email: cbouatmailru(a)gmail.com

13 years, 2 months

[ACTIVITY] (Rajendra Nayak) Jan 23 - Feb 03

by Rajendra Nayak

== Rajendra Nayak <rnayak> == === Highlights === * Started writing a generic system control module driver for OMAP2/3/4, with exported api's for system control read/write. Needed mainly for omap-hsmmc-dt adaptation as omap-hsmmc currently does system control read/writes from machine code by passing function pointers to the driver. This needs cleanup before omap_hsmmc can work with DT. * Cleaned up the use/abuse of pdev->id across omap-hsmmc driver. Again a pre-requisite step before omap-hsmmc can work with DT. * Reworked TWL DT regulator patches based on off-list discussions with Benoit to make non-DT and DT both use a common lookup table. * Caught-up on all the pinctrl DT discussions on list while I was off 3 weeks in nice. === Plans === * Repost v3 of TWL DT series. Need to wait for Benoit to post his which adds twl*.dtsi files. * Continue work on system control module driver. * omap-hsmmc DT adaptation. * Attend connect. === Misc === * Was off on 27th and 26th was a holiday in India.

13 years, 2 months

[ACTIVITY] (John Stultz) Jan 30 - Feb 3

by John Stultz

=== Highlights === * Sent android-alarm drivers to Greg for inclusion into staging. He's currently changing employers, but said he's planning on merging them into staging for 3.4. * Worked on getting origen board booting with Android on a vanilla 3.3-rc kernel. Got close, even have boot console graphics working, but for some reason gralloc is failing. Will try to work this out over connect. * Got Panda board ready for Android demo running on a (almost) vanilla linux 3.3-rc2 kernel. Only required a single ~4 line patch. * Spent a good chunk of the week trying to integrate the range-tree implementation into fadvise volatile work. Unfortunately this was much more difficult then I expected, and I had three or four false starts that required entirely rearchitecting the approach each time. Almost gave up, but finally last night I came up with a reasonable approach, and have integrated a first pass. Wanted to send something out by friday, but its just not well enough tested, so I'll hopefully get it out next week. * Sent out my 3.4 queue to tglx for merging. * Reviewed a couple of ELC presentations and provided feedback. * Ran email meeting for Android Kernel Sub-team === Plans === * Lots of connect stuff * Finish and send out first working range-tree fadivse volatile implementation * Do presentation on merge_config.sh script * Work on origen Android issues w/ vanilla kernel. * Present on Linaro's Android upstreaming === Issues === NA

13 years, 2 months

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